Rahul Dahiya / Mbed OS STM32F7 Ethernet

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mbed-os/features/mbedtls/src/ecp.c@0:fb8047b156bb, 2020-01-15 (annotated)

Committer:
rahul_dahiya
Date:
Wed Jan 15 15:57:15 2020 +0530
Revision:
0:fb8047b156bb
STM32F7 LWIP

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rahul_dahiya 0:fb8047b156bb 1 /*
rahul_dahiya 0:fb8047b156bb 2 * Elliptic curves over GF(p): generic functions
rahul_dahiya 0:fb8047b156bb 3 *
rahul_dahiya 0:fb8047b156bb 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
rahul_dahiya 0:fb8047b156bb 5 * SPDX-License-Identifier: Apache-2.0
rahul_dahiya 0:fb8047b156bb 6 *
rahul_dahiya 0:fb8047b156bb 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
rahul_dahiya 0:fb8047b156bb 8 * not use this file except in compliance with the License.
rahul_dahiya 0:fb8047b156bb 9 * You may obtain a copy of the License at
rahul_dahiya 0:fb8047b156bb 10 *
rahul_dahiya 0:fb8047b156bb 11 * http://www.apache.org/licenses/LICENSE-2.0
rahul_dahiya 0:fb8047b156bb 12 *
rahul_dahiya 0:fb8047b156bb 13 * Unless required by applicable law or agreed to in writing, software
rahul_dahiya 0:fb8047b156bb 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
rahul_dahiya 0:fb8047b156bb 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rahul_dahiya 0:fb8047b156bb 16 * See the License for the specific language governing permissions and
rahul_dahiya 0:fb8047b156bb 17 * limitations under the License.
rahul_dahiya 0:fb8047b156bb 18 *
rahul_dahiya 0:fb8047b156bb 19 * This file is part of mbed TLS (https://tls.mbed.org)
rahul_dahiya 0:fb8047b156bb 20 */
rahul_dahiya 0:fb8047b156bb 21
rahul_dahiya 0:fb8047b156bb 22 /*
rahul_dahiya 0:fb8047b156bb 23 * References:
rahul_dahiya 0:fb8047b156bb 24 *
rahul_dahiya 0:fb8047b156bb 25 * SEC1 http://www.secg.org/index.php?action=secg,docs_secg
rahul_dahiya 0:fb8047b156bb 26 * GECC = Guide to Elliptic Curve Cryptography - Hankerson, Menezes, Vanstone
rahul_dahiya 0:fb8047b156bb 27 * FIPS 186-3 http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf
rahul_dahiya 0:fb8047b156bb 28 * RFC 4492 for the related TLS structures and constants
rahul_dahiya 0:fb8047b156bb 29 *
rahul_dahiya 0:fb8047b156bb 30 * [Curve25519] http://cr.yp.to/ecdh/curve25519-20060209.pdf
rahul_dahiya 0:fb8047b156bb 31 *
rahul_dahiya 0:fb8047b156bb 32 * [2] CORON, Jean-S'ebastien. Resistance against differential power analysis
rahul_dahiya 0:fb8047b156bb 33 * for elliptic curve cryptosystems. In : Cryptographic Hardware and
rahul_dahiya 0:fb8047b156bb 34 * Embedded Systems. Springer Berlin Heidelberg, 1999. p. 292-302.
rahul_dahiya 0:fb8047b156bb 35 * <http://link.springer.com/chapter/10.1007/3-540-48059-5_25>
rahul_dahiya 0:fb8047b156bb 36 *
rahul_dahiya 0:fb8047b156bb 37 * [3] HEDABOU, Mustapha, PINEL, Pierre, et B'EN'ETEAU, Lucien. A comb method to
rahul_dahiya 0:fb8047b156bb 38 * render ECC resistant against Side Channel Attacks. IACR Cryptology
rahul_dahiya 0:fb8047b156bb 39 * ePrint Archive, 2004, vol. 2004, p. 342.
rahul_dahiya 0:fb8047b156bb 40 * <http://eprint.iacr.org/2004/342.pdf>
rahul_dahiya 0:fb8047b156bb 41 */
rahul_dahiya 0:fb8047b156bb 42
rahul_dahiya 0:fb8047b156bb 43 #if !defined(MBEDTLS_CONFIG_FILE)
rahul_dahiya 0:fb8047b156bb 44 #include "mbedtls/config.h"
rahul_dahiya 0:fb8047b156bb 45 #else
rahul_dahiya 0:fb8047b156bb 46 #include MBEDTLS_CONFIG_FILE
rahul_dahiya 0:fb8047b156bb 47 #endif
rahul_dahiya 0:fb8047b156bb 48
rahul_dahiya 0:fb8047b156bb 49 #if defined(MBEDTLS_ECP_C)
rahul_dahiya 0:fb8047b156bb 50
rahul_dahiya 0:fb8047b156bb 51 #include "mbedtls/ecp.h"
rahul_dahiya 0:fb8047b156bb 52 #include "mbedtls/threading.h"
rahul_dahiya 0:fb8047b156bb 53
rahul_dahiya 0:fb8047b156bb 54 #include <string.h>
rahul_dahiya 0:fb8047b156bb 55
rahul_dahiya 0:fb8047b156bb 56 #if !defined(MBEDTLS_ECP_ALT)
rahul_dahiya 0:fb8047b156bb 57
rahul_dahiya 0:fb8047b156bb 58 #if defined(MBEDTLS_PLATFORM_C)
rahul_dahiya 0:fb8047b156bb 59 #include "mbedtls/platform.h"
rahul_dahiya 0:fb8047b156bb 60 #else
rahul_dahiya 0:fb8047b156bb 61 #include <stdlib.h>
rahul_dahiya 0:fb8047b156bb 62 #include <stdio.h>
rahul_dahiya 0:fb8047b156bb 63 #define mbedtls_printf printf
rahul_dahiya 0:fb8047b156bb 64 #define mbedtls_calloc calloc
rahul_dahiya 0:fb8047b156bb 65 #define mbedtls_free free
rahul_dahiya 0:fb8047b156bb 66 #endif
rahul_dahiya 0:fb8047b156bb 67
rahul_dahiya 0:fb8047b156bb 68 #include "mbedtls/ecp_internal.h"
rahul_dahiya 0:fb8047b156bb 69
rahul_dahiya 0:fb8047b156bb 70 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
rahul_dahiya 0:fb8047b156bb 71 !defined(inline) && !defined(__cplusplus)
rahul_dahiya 0:fb8047b156bb 72 #define inline __inline
rahul_dahiya 0:fb8047b156bb 73 #endif
rahul_dahiya 0:fb8047b156bb 74
rahul_dahiya 0:fb8047b156bb 75 /* Implementation that should never be optimized out by the compiler */
rahul_dahiya 0:fb8047b156bb 76 static void mbedtls_zeroize( void *v, size_t n ) {
rahul_dahiya 0:fb8047b156bb 77 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
rahul_dahiya 0:fb8047b156bb 78 }
rahul_dahiya 0:fb8047b156bb 79
rahul_dahiya 0:fb8047b156bb 80 #if defined(MBEDTLS_SELF_TEST)
rahul_dahiya 0:fb8047b156bb 81 /*
rahul_dahiya 0:fb8047b156bb 82 * Counts of point addition and doubling, and field multiplications.
rahul_dahiya 0:fb8047b156bb 83 * Used to test resistance of point multiplication to simple timing attacks.
rahul_dahiya 0:fb8047b156bb 84 */
rahul_dahiya 0:fb8047b156bb 85 static unsigned long add_count, dbl_count, mul_count;
rahul_dahiya 0:fb8047b156bb 86 #endif
rahul_dahiya 0:fb8047b156bb 87
rahul_dahiya 0:fb8047b156bb 88 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 89 defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 90 defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 91 defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 92 defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 93 defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 94 defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 95 defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 96 defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 97 defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) || \
rahul_dahiya 0:fb8047b156bb 98 defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
rahul_dahiya 0:fb8047b156bb 99 #define ECP_SHORTWEIERSTRASS
rahul_dahiya 0:fb8047b156bb 100 #endif
rahul_dahiya 0:fb8047b156bb 101
rahul_dahiya 0:fb8047b156bb 102 #if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
rahul_dahiya 0:fb8047b156bb 103 #define ECP_MONTGOMERY
rahul_dahiya 0:fb8047b156bb 104 #endif
rahul_dahiya 0:fb8047b156bb 105
rahul_dahiya 0:fb8047b156bb 106 /*
rahul_dahiya 0:fb8047b156bb 107 * Curve types: internal for now, might be exposed later
rahul_dahiya 0:fb8047b156bb 108 */
rahul_dahiya 0:fb8047b156bb 109 typedef enum
rahul_dahiya 0:fb8047b156bb 110 {
rahul_dahiya 0:fb8047b156bb 111 ECP_TYPE_NONE = 0,
rahul_dahiya 0:fb8047b156bb 112 ECP_TYPE_SHORT_WEIERSTRASS, /* y^2 = x^3 + a x + b */
rahul_dahiya 0:fb8047b156bb 113 ECP_TYPE_MONTGOMERY, /* y^2 = x^3 + a x^2 + x */
rahul_dahiya 0:fb8047b156bb 114 } ecp_curve_type;
rahul_dahiya 0:fb8047b156bb 115
rahul_dahiya 0:fb8047b156bb 116 /*
rahul_dahiya 0:fb8047b156bb 117 * List of supported curves:
rahul_dahiya 0:fb8047b156bb 118 * - internal ID
rahul_dahiya 0:fb8047b156bb 119 * - TLS NamedCurve ID (RFC 4492 sec. 5.1.1, RFC 7071 sec. 2)
rahul_dahiya 0:fb8047b156bb 120 * - size in bits
rahul_dahiya 0:fb8047b156bb 121 * - readable name
rahul_dahiya 0:fb8047b156bb 122 *
rahul_dahiya 0:fb8047b156bb 123 * Curves are listed in order: largest curves first, and for a given size,
rahul_dahiya 0:fb8047b156bb 124 * fastest curves first. This provides the default order for the SSL module.
rahul_dahiya 0:fb8047b156bb 125 *
rahul_dahiya 0:fb8047b156bb 126 * Reminder: update profiles in x509_crt.c when adding a new curves!
rahul_dahiya 0:fb8047b156bb 127 */
rahul_dahiya 0:fb8047b156bb 128 static const mbedtls_ecp_curve_info ecp_supported_curves[] =
rahul_dahiya 0:fb8047b156bb 129 {
rahul_dahiya 0:fb8047b156bb 130 #if defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 131 { MBEDTLS_ECP_DP_SECP521R1, 25, 521, "secp521r1" },
rahul_dahiya 0:fb8047b156bb 132 #endif
rahul_dahiya 0:fb8047b156bb 133 #if defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 134 { MBEDTLS_ECP_DP_BP512R1, 28, 512, "brainpoolP512r1" },
rahul_dahiya 0:fb8047b156bb 135 #endif
rahul_dahiya 0:fb8047b156bb 136 #if defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 137 { MBEDTLS_ECP_DP_SECP384R1, 24, 384, "secp384r1" },
rahul_dahiya 0:fb8047b156bb 138 #endif
rahul_dahiya 0:fb8047b156bb 139 #if defined(MBEDTLS_ECP_DP_BP384R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 140 { MBEDTLS_ECP_DP_BP384R1, 27, 384, "brainpoolP384r1" },
rahul_dahiya 0:fb8047b156bb 141 #endif
rahul_dahiya 0:fb8047b156bb 142 #if defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 143 { MBEDTLS_ECP_DP_SECP256R1, 23, 256, "secp256r1" },
rahul_dahiya 0:fb8047b156bb 144 #endif
rahul_dahiya 0:fb8047b156bb 145 #if defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
rahul_dahiya 0:fb8047b156bb 146 { MBEDTLS_ECP_DP_SECP256K1, 22, 256, "secp256k1" },
rahul_dahiya 0:fb8047b156bb 147 #endif
rahul_dahiya 0:fb8047b156bb 148 #if defined(MBEDTLS_ECP_DP_BP256R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 149 { MBEDTLS_ECP_DP_BP256R1, 26, 256, "brainpoolP256r1" },
rahul_dahiya 0:fb8047b156bb 150 #endif
rahul_dahiya 0:fb8047b156bb 151 #if defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 152 { MBEDTLS_ECP_DP_SECP224R1, 21, 224, "secp224r1" },
rahul_dahiya 0:fb8047b156bb 153 #endif
rahul_dahiya 0:fb8047b156bb 154 #if defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED)
rahul_dahiya 0:fb8047b156bb 155 { MBEDTLS_ECP_DP_SECP224K1, 20, 224, "secp224k1" },
rahul_dahiya 0:fb8047b156bb 156 #endif
rahul_dahiya 0:fb8047b156bb 157 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 158 { MBEDTLS_ECP_DP_SECP192R1, 19, 192, "secp192r1" },
rahul_dahiya 0:fb8047b156bb 159 #endif
rahul_dahiya 0:fb8047b156bb 160 #if defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED)
rahul_dahiya 0:fb8047b156bb 161 { MBEDTLS_ECP_DP_SECP192K1, 18, 192, "secp192k1" },
rahul_dahiya 0:fb8047b156bb 162 #endif
rahul_dahiya 0:fb8047b156bb 163 { MBEDTLS_ECP_DP_NONE, 0, 0, NULL },
rahul_dahiya 0:fb8047b156bb 164 };
rahul_dahiya 0:fb8047b156bb 165
rahul_dahiya 0:fb8047b156bb 166 #define ECP_NB_CURVES sizeof( ecp_supported_curves ) / \
rahul_dahiya 0:fb8047b156bb 167 sizeof( ecp_supported_curves[0] )
rahul_dahiya 0:fb8047b156bb 168
rahul_dahiya 0:fb8047b156bb 169 static mbedtls_ecp_group_id ecp_supported_grp_id[ECP_NB_CURVES];
rahul_dahiya 0:fb8047b156bb 170
rahul_dahiya 0:fb8047b156bb 171 /*
rahul_dahiya 0:fb8047b156bb 172 * List of supported curves and associated info
rahul_dahiya 0:fb8047b156bb 173 */
rahul_dahiya 0:fb8047b156bb 174 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_list( void )
rahul_dahiya 0:fb8047b156bb 175 {
rahul_dahiya 0:fb8047b156bb 176 return( ecp_supported_curves );
rahul_dahiya 0:fb8047b156bb 177 }
rahul_dahiya 0:fb8047b156bb 178
rahul_dahiya 0:fb8047b156bb 179 /*
rahul_dahiya 0:fb8047b156bb 180 * List of supported curves, group ID only
rahul_dahiya 0:fb8047b156bb 181 */
rahul_dahiya 0:fb8047b156bb 182 const mbedtls_ecp_group_id *mbedtls_ecp_grp_id_list( void )
rahul_dahiya 0:fb8047b156bb 183 {
rahul_dahiya 0:fb8047b156bb 184 static int init_done = 0;
rahul_dahiya 0:fb8047b156bb 185
rahul_dahiya 0:fb8047b156bb 186 if( ! init_done )
rahul_dahiya 0:fb8047b156bb 187 {
rahul_dahiya 0:fb8047b156bb 188 size_t i = 0;
rahul_dahiya 0:fb8047b156bb 189 const mbedtls_ecp_curve_info *curve_info;
rahul_dahiya 0:fb8047b156bb 190
rahul_dahiya 0:fb8047b156bb 191 for( curve_info = mbedtls_ecp_curve_list();
rahul_dahiya 0:fb8047b156bb 192 curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
rahul_dahiya 0:fb8047b156bb 193 curve_info++ )
rahul_dahiya 0:fb8047b156bb 194 {
rahul_dahiya 0:fb8047b156bb 195 ecp_supported_grp_id[i++] = curve_info->grp_id;
rahul_dahiya 0:fb8047b156bb 196 }
rahul_dahiya 0:fb8047b156bb 197 ecp_supported_grp_id[i] = MBEDTLS_ECP_DP_NONE;
rahul_dahiya 0:fb8047b156bb 198
rahul_dahiya 0:fb8047b156bb 199 init_done = 1;
rahul_dahiya 0:fb8047b156bb 200 }
rahul_dahiya 0:fb8047b156bb 201
rahul_dahiya 0:fb8047b156bb 202 return( ecp_supported_grp_id );
rahul_dahiya 0:fb8047b156bb 203 }
rahul_dahiya 0:fb8047b156bb 204
rahul_dahiya 0:fb8047b156bb 205 /*
rahul_dahiya 0:fb8047b156bb 206 * Get the curve info for the internal identifier
rahul_dahiya 0:fb8047b156bb 207 */
rahul_dahiya 0:fb8047b156bb 208 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_grp_id( mbedtls_ecp_group_id grp_id )
rahul_dahiya 0:fb8047b156bb 209 {
rahul_dahiya 0:fb8047b156bb 210 const mbedtls_ecp_curve_info *curve_info;
rahul_dahiya 0:fb8047b156bb 211
rahul_dahiya 0:fb8047b156bb 212 for( curve_info = mbedtls_ecp_curve_list();
rahul_dahiya 0:fb8047b156bb 213 curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
rahul_dahiya 0:fb8047b156bb 214 curve_info++ )
rahul_dahiya 0:fb8047b156bb 215 {
rahul_dahiya 0:fb8047b156bb 216 if( curve_info->grp_id == grp_id )
rahul_dahiya 0:fb8047b156bb 217 return( curve_info );
rahul_dahiya 0:fb8047b156bb 218 }
rahul_dahiya 0:fb8047b156bb 219
rahul_dahiya 0:fb8047b156bb 220 return( NULL );
rahul_dahiya 0:fb8047b156bb 221 }
rahul_dahiya 0:fb8047b156bb 222
rahul_dahiya 0:fb8047b156bb 223 /*
rahul_dahiya 0:fb8047b156bb 224 * Get the curve info from the TLS identifier
rahul_dahiya 0:fb8047b156bb 225 */
rahul_dahiya 0:fb8047b156bb 226 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_tls_id( uint16_t tls_id )
rahul_dahiya 0:fb8047b156bb 227 {
rahul_dahiya 0:fb8047b156bb 228 const mbedtls_ecp_curve_info *curve_info;
rahul_dahiya 0:fb8047b156bb 229
rahul_dahiya 0:fb8047b156bb 230 for( curve_info = mbedtls_ecp_curve_list();
rahul_dahiya 0:fb8047b156bb 231 curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
rahul_dahiya 0:fb8047b156bb 232 curve_info++ )
rahul_dahiya 0:fb8047b156bb 233 {
rahul_dahiya 0:fb8047b156bb 234 if( curve_info->tls_id == tls_id )
rahul_dahiya 0:fb8047b156bb 235 return( curve_info );
rahul_dahiya 0:fb8047b156bb 236 }
rahul_dahiya 0:fb8047b156bb 237
rahul_dahiya 0:fb8047b156bb 238 return( NULL );
rahul_dahiya 0:fb8047b156bb 239 }
rahul_dahiya 0:fb8047b156bb 240
rahul_dahiya 0:fb8047b156bb 241 /*
rahul_dahiya 0:fb8047b156bb 242 * Get the curve info from the name
rahul_dahiya 0:fb8047b156bb 243 */
rahul_dahiya 0:fb8047b156bb 244 const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_name( const char *name )
rahul_dahiya 0:fb8047b156bb 245 {
rahul_dahiya 0:fb8047b156bb 246 const mbedtls_ecp_curve_info *curve_info;
rahul_dahiya 0:fb8047b156bb 247
rahul_dahiya 0:fb8047b156bb 248 for( curve_info = mbedtls_ecp_curve_list();
rahul_dahiya 0:fb8047b156bb 249 curve_info->grp_id != MBEDTLS_ECP_DP_NONE;
rahul_dahiya 0:fb8047b156bb 250 curve_info++ )
rahul_dahiya 0:fb8047b156bb 251 {
rahul_dahiya 0:fb8047b156bb 252 if( strcmp( curve_info->name, name ) == 0 )
rahul_dahiya 0:fb8047b156bb 253 return( curve_info );
rahul_dahiya 0:fb8047b156bb 254 }
rahul_dahiya 0:fb8047b156bb 255
rahul_dahiya 0:fb8047b156bb 256 return( NULL );
rahul_dahiya 0:fb8047b156bb 257 }
rahul_dahiya 0:fb8047b156bb 258
rahul_dahiya 0:fb8047b156bb 259 /*
rahul_dahiya 0:fb8047b156bb 260 * Get the type of a curve
rahul_dahiya 0:fb8047b156bb 261 */
rahul_dahiya 0:fb8047b156bb 262 static inline ecp_curve_type ecp_get_type( const mbedtls_ecp_group *grp )
rahul_dahiya 0:fb8047b156bb 263 {
rahul_dahiya 0:fb8047b156bb 264 if( grp->G.X.p == NULL )
rahul_dahiya 0:fb8047b156bb 265 return( ECP_TYPE_NONE );
rahul_dahiya 0:fb8047b156bb 266
rahul_dahiya 0:fb8047b156bb 267 if( grp->G.Y.p == NULL )
rahul_dahiya 0:fb8047b156bb 268 return( ECP_TYPE_MONTGOMERY );
rahul_dahiya 0:fb8047b156bb 269 else
rahul_dahiya 0:fb8047b156bb 270 return( ECP_TYPE_SHORT_WEIERSTRASS );
rahul_dahiya 0:fb8047b156bb 271 }
rahul_dahiya 0:fb8047b156bb 272
rahul_dahiya 0:fb8047b156bb 273 /*
rahul_dahiya 0:fb8047b156bb 274 * Initialize (the components of) a point
rahul_dahiya 0:fb8047b156bb 275 */
rahul_dahiya 0:fb8047b156bb 276 void mbedtls_ecp_point_init( mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 277 {
rahul_dahiya 0:fb8047b156bb 278 if( pt == NULL )
rahul_dahiya 0:fb8047b156bb 279 return;
rahul_dahiya 0:fb8047b156bb 280
rahul_dahiya 0:fb8047b156bb 281 mbedtls_mpi_init( &pt->X );
rahul_dahiya 0:fb8047b156bb 282 mbedtls_mpi_init( &pt->Y );
rahul_dahiya 0:fb8047b156bb 283 mbedtls_mpi_init( &pt->Z );
rahul_dahiya 0:fb8047b156bb 284 }
rahul_dahiya 0:fb8047b156bb 285
rahul_dahiya 0:fb8047b156bb 286 /*
rahul_dahiya 0:fb8047b156bb 287 * Initialize (the components of) a group
rahul_dahiya 0:fb8047b156bb 288 */
rahul_dahiya 0:fb8047b156bb 289 void mbedtls_ecp_group_init( mbedtls_ecp_group *grp )
rahul_dahiya 0:fb8047b156bb 290 {
rahul_dahiya 0:fb8047b156bb 291 if( grp == NULL )
rahul_dahiya 0:fb8047b156bb 292 return;
rahul_dahiya 0:fb8047b156bb 293
rahul_dahiya 0:fb8047b156bb 294 memset( grp, 0, sizeof( mbedtls_ecp_group ) );
rahul_dahiya 0:fb8047b156bb 295 }
rahul_dahiya 0:fb8047b156bb 296
rahul_dahiya 0:fb8047b156bb 297 /*
rahul_dahiya 0:fb8047b156bb 298 * Initialize (the components of) a key pair
rahul_dahiya 0:fb8047b156bb 299 */
rahul_dahiya 0:fb8047b156bb 300 void mbedtls_ecp_keypair_init( mbedtls_ecp_keypair *key )
rahul_dahiya 0:fb8047b156bb 301 {
rahul_dahiya 0:fb8047b156bb 302 if( key == NULL )
rahul_dahiya 0:fb8047b156bb 303 return;
rahul_dahiya 0:fb8047b156bb 304
rahul_dahiya 0:fb8047b156bb 305 mbedtls_ecp_group_init( &key->grp );
rahul_dahiya 0:fb8047b156bb 306 mbedtls_mpi_init( &key->d );
rahul_dahiya 0:fb8047b156bb 307 mbedtls_ecp_point_init( &key->Q );
rahul_dahiya 0:fb8047b156bb 308 }
rahul_dahiya 0:fb8047b156bb 309
rahul_dahiya 0:fb8047b156bb 310 /*
rahul_dahiya 0:fb8047b156bb 311 * Unallocate (the components of) a point
rahul_dahiya 0:fb8047b156bb 312 */
rahul_dahiya 0:fb8047b156bb 313 void mbedtls_ecp_point_free( mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 314 {
rahul_dahiya 0:fb8047b156bb 315 if( pt == NULL )
rahul_dahiya 0:fb8047b156bb 316 return;
rahul_dahiya 0:fb8047b156bb 317
rahul_dahiya 0:fb8047b156bb 318 mbedtls_mpi_free( &( pt->X ) );
rahul_dahiya 0:fb8047b156bb 319 mbedtls_mpi_free( &( pt->Y ) );
rahul_dahiya 0:fb8047b156bb 320 mbedtls_mpi_free( &( pt->Z ) );
rahul_dahiya 0:fb8047b156bb 321 }
rahul_dahiya 0:fb8047b156bb 322
rahul_dahiya 0:fb8047b156bb 323 /*
rahul_dahiya 0:fb8047b156bb 324 * Unallocate (the components of) a group
rahul_dahiya 0:fb8047b156bb 325 */
rahul_dahiya 0:fb8047b156bb 326 void mbedtls_ecp_group_free( mbedtls_ecp_group *grp )
rahul_dahiya 0:fb8047b156bb 327 {
rahul_dahiya 0:fb8047b156bb 328 size_t i;
rahul_dahiya 0:fb8047b156bb 329
rahul_dahiya 0:fb8047b156bb 330 if( grp == NULL )
rahul_dahiya 0:fb8047b156bb 331 return;
rahul_dahiya 0:fb8047b156bb 332
rahul_dahiya 0:fb8047b156bb 333 if( grp->h != 1 )
rahul_dahiya 0:fb8047b156bb 334 {
rahul_dahiya 0:fb8047b156bb 335 mbedtls_mpi_free( &grp->P );
rahul_dahiya 0:fb8047b156bb 336 mbedtls_mpi_free( &grp->A );
rahul_dahiya 0:fb8047b156bb 337 mbedtls_mpi_free( &grp->B );
rahul_dahiya 0:fb8047b156bb 338 mbedtls_ecp_point_free( &grp->G );
rahul_dahiya 0:fb8047b156bb 339 mbedtls_mpi_free( &grp->N );
rahul_dahiya 0:fb8047b156bb 340 }
rahul_dahiya 0:fb8047b156bb 341
rahul_dahiya 0:fb8047b156bb 342 if( grp->T != NULL )
rahul_dahiya 0:fb8047b156bb 343 {
rahul_dahiya 0:fb8047b156bb 344 for( i = 0; i < grp->T_size; i++ )
rahul_dahiya 0:fb8047b156bb 345 mbedtls_ecp_point_free( &grp->T[i] );
rahul_dahiya 0:fb8047b156bb 346 mbedtls_free( grp->T );
rahul_dahiya 0:fb8047b156bb 347 }
rahul_dahiya 0:fb8047b156bb 348
rahul_dahiya 0:fb8047b156bb 349 mbedtls_zeroize( grp, sizeof( mbedtls_ecp_group ) );
rahul_dahiya 0:fb8047b156bb 350 }
rahul_dahiya 0:fb8047b156bb 351
rahul_dahiya 0:fb8047b156bb 352 /*
rahul_dahiya 0:fb8047b156bb 353 * Unallocate (the components of) a key pair
rahul_dahiya 0:fb8047b156bb 354 */
rahul_dahiya 0:fb8047b156bb 355 void mbedtls_ecp_keypair_free( mbedtls_ecp_keypair *key )
rahul_dahiya 0:fb8047b156bb 356 {
rahul_dahiya 0:fb8047b156bb 357 if( key == NULL )
rahul_dahiya 0:fb8047b156bb 358 return;
rahul_dahiya 0:fb8047b156bb 359
rahul_dahiya 0:fb8047b156bb 360 mbedtls_ecp_group_free( &key->grp );
rahul_dahiya 0:fb8047b156bb 361 mbedtls_mpi_free( &key->d );
rahul_dahiya 0:fb8047b156bb 362 mbedtls_ecp_point_free( &key->Q );
rahul_dahiya 0:fb8047b156bb 363 }
rahul_dahiya 0:fb8047b156bb 364
rahul_dahiya 0:fb8047b156bb 365 /*
rahul_dahiya 0:fb8047b156bb 366 * Copy the contents of a point
rahul_dahiya 0:fb8047b156bb 367 */
rahul_dahiya 0:fb8047b156bb 368 int mbedtls_ecp_copy( mbedtls_ecp_point *P, const mbedtls_ecp_point *Q )
rahul_dahiya 0:fb8047b156bb 369 {
rahul_dahiya 0:fb8047b156bb 370 int ret;
rahul_dahiya 0:fb8047b156bb 371
rahul_dahiya 0:fb8047b156bb 372 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &P->X, &Q->X ) );
rahul_dahiya 0:fb8047b156bb 373 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &P->Y, &Q->Y ) );
rahul_dahiya 0:fb8047b156bb 374 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &P->Z, &Q->Z ) );
rahul_dahiya 0:fb8047b156bb 375
rahul_dahiya 0:fb8047b156bb 376 cleanup:
rahul_dahiya 0:fb8047b156bb 377 return( ret );
rahul_dahiya 0:fb8047b156bb 378 }
rahul_dahiya 0:fb8047b156bb 379
rahul_dahiya 0:fb8047b156bb 380 /*
rahul_dahiya 0:fb8047b156bb 381 * Copy the contents of a group object
rahul_dahiya 0:fb8047b156bb 382 */
rahul_dahiya 0:fb8047b156bb 383 int mbedtls_ecp_group_copy( mbedtls_ecp_group *dst, const mbedtls_ecp_group *src )
rahul_dahiya 0:fb8047b156bb 384 {
rahul_dahiya 0:fb8047b156bb 385 return mbedtls_ecp_group_load( dst, src->id );
rahul_dahiya 0:fb8047b156bb 386 }
rahul_dahiya 0:fb8047b156bb 387
rahul_dahiya 0:fb8047b156bb 388 /*
rahul_dahiya 0:fb8047b156bb 389 * Set point to zero
rahul_dahiya 0:fb8047b156bb 390 */
rahul_dahiya 0:fb8047b156bb 391 int mbedtls_ecp_set_zero( mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 392 {
rahul_dahiya 0:fb8047b156bb 393 int ret;
rahul_dahiya 0:fb8047b156bb 394
rahul_dahiya 0:fb8047b156bb 395 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->X , 1 ) );
rahul_dahiya 0:fb8047b156bb 396 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->Y , 1 ) );
rahul_dahiya 0:fb8047b156bb 397 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->Z , 0 ) );
rahul_dahiya 0:fb8047b156bb 398
rahul_dahiya 0:fb8047b156bb 399 cleanup:
rahul_dahiya 0:fb8047b156bb 400 return( ret );
rahul_dahiya 0:fb8047b156bb 401 }
rahul_dahiya 0:fb8047b156bb 402
rahul_dahiya 0:fb8047b156bb 403 /*
rahul_dahiya 0:fb8047b156bb 404 * Tell if a point is zero
rahul_dahiya 0:fb8047b156bb 405 */
rahul_dahiya 0:fb8047b156bb 406 int mbedtls_ecp_is_zero( mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 407 {
rahul_dahiya 0:fb8047b156bb 408 return( mbedtls_mpi_cmp_int( &pt->Z, 0 ) == 0 );
rahul_dahiya 0:fb8047b156bb 409 }
rahul_dahiya 0:fb8047b156bb 410
rahul_dahiya 0:fb8047b156bb 411 /*
rahul_dahiya 0:fb8047b156bb 412 * Compare two points lazyly
rahul_dahiya 0:fb8047b156bb 413 */
rahul_dahiya 0:fb8047b156bb 414 int mbedtls_ecp_point_cmp( const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 415 const mbedtls_ecp_point *Q )
rahul_dahiya 0:fb8047b156bb 416 {
rahul_dahiya 0:fb8047b156bb 417 if( mbedtls_mpi_cmp_mpi( &P->X, &Q->X ) == 0 &&
rahul_dahiya 0:fb8047b156bb 418 mbedtls_mpi_cmp_mpi( &P->Y, &Q->Y ) == 0 &&
rahul_dahiya 0:fb8047b156bb 419 mbedtls_mpi_cmp_mpi( &P->Z, &Q->Z ) == 0 )
rahul_dahiya 0:fb8047b156bb 420 {
rahul_dahiya 0:fb8047b156bb 421 return( 0 );
rahul_dahiya 0:fb8047b156bb 422 }
rahul_dahiya 0:fb8047b156bb 423
rahul_dahiya 0:fb8047b156bb 424 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 425 }
rahul_dahiya 0:fb8047b156bb 426
rahul_dahiya 0:fb8047b156bb 427 /*
rahul_dahiya 0:fb8047b156bb 428 * Import a non-zero point from ASCII strings
rahul_dahiya 0:fb8047b156bb 429 */
rahul_dahiya 0:fb8047b156bb 430 int mbedtls_ecp_point_read_string( mbedtls_ecp_point *P, int radix,
rahul_dahiya 0:fb8047b156bb 431 const char *x, const char *y )
rahul_dahiya 0:fb8047b156bb 432 {
rahul_dahiya 0:fb8047b156bb 433 int ret;
rahul_dahiya 0:fb8047b156bb 434
rahul_dahiya 0:fb8047b156bb 435 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &P->X, radix, x ) );
rahul_dahiya 0:fb8047b156bb 436 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &P->Y, radix, y ) );
rahul_dahiya 0:fb8047b156bb 437 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &P->Z, 1 ) );
rahul_dahiya 0:fb8047b156bb 438
rahul_dahiya 0:fb8047b156bb 439 cleanup:
rahul_dahiya 0:fb8047b156bb 440 return( ret );
rahul_dahiya 0:fb8047b156bb 441 }
rahul_dahiya 0:fb8047b156bb 442
rahul_dahiya 0:fb8047b156bb 443 /*
rahul_dahiya 0:fb8047b156bb 444 * Export a point into unsigned binary data (SEC1 2.3.3)
rahul_dahiya 0:fb8047b156bb 445 */
rahul_dahiya 0:fb8047b156bb 446 int mbedtls_ecp_point_write_binary( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 447 int format, size_t *olen,
rahul_dahiya 0:fb8047b156bb 448 unsigned char *buf, size_t buflen )
rahul_dahiya 0:fb8047b156bb 449 {
rahul_dahiya 0:fb8047b156bb 450 int ret = 0;
rahul_dahiya 0:fb8047b156bb 451 size_t plen;
rahul_dahiya 0:fb8047b156bb 452
rahul_dahiya 0:fb8047b156bb 453 if( format != MBEDTLS_ECP_PF_UNCOMPRESSED &&
rahul_dahiya 0:fb8047b156bb 454 format != MBEDTLS_ECP_PF_COMPRESSED )
rahul_dahiya 0:fb8047b156bb 455 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 456
rahul_dahiya 0:fb8047b156bb 457 /*
rahul_dahiya 0:fb8047b156bb 458 * Common case: P == 0
rahul_dahiya 0:fb8047b156bb 459 */
rahul_dahiya 0:fb8047b156bb 460 if( mbedtls_mpi_cmp_int( &P->Z, 0 ) == 0 )
rahul_dahiya 0:fb8047b156bb 461 {
rahul_dahiya 0:fb8047b156bb 462 if( buflen < 1 )
rahul_dahiya 0:fb8047b156bb 463 return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
rahul_dahiya 0:fb8047b156bb 464
rahul_dahiya 0:fb8047b156bb 465 buf[0] = 0x00;
rahul_dahiya 0:fb8047b156bb 466 *olen = 1;
rahul_dahiya 0:fb8047b156bb 467
rahul_dahiya 0:fb8047b156bb 468 return( 0 );
rahul_dahiya 0:fb8047b156bb 469 }
rahul_dahiya 0:fb8047b156bb 470
rahul_dahiya 0:fb8047b156bb 471 plen = mbedtls_mpi_size( &grp->P );
rahul_dahiya 0:fb8047b156bb 472
rahul_dahiya 0:fb8047b156bb 473 if( format == MBEDTLS_ECP_PF_UNCOMPRESSED )
rahul_dahiya 0:fb8047b156bb 474 {
rahul_dahiya 0:fb8047b156bb 475 *olen = 2 * plen + 1;
rahul_dahiya 0:fb8047b156bb 476
rahul_dahiya 0:fb8047b156bb 477 if( buflen < *olen )
rahul_dahiya 0:fb8047b156bb 478 return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
rahul_dahiya 0:fb8047b156bb 479
rahul_dahiya 0:fb8047b156bb 480 buf[0] = 0x04;
rahul_dahiya 0:fb8047b156bb 481 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &P->X, buf + 1, plen ) );
rahul_dahiya 0:fb8047b156bb 482 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &P->Y, buf + 1 + plen, plen ) );
rahul_dahiya 0:fb8047b156bb 483 }
rahul_dahiya 0:fb8047b156bb 484 else if( format == MBEDTLS_ECP_PF_COMPRESSED )
rahul_dahiya 0:fb8047b156bb 485 {
rahul_dahiya 0:fb8047b156bb 486 *olen = plen + 1;
rahul_dahiya 0:fb8047b156bb 487
rahul_dahiya 0:fb8047b156bb 488 if( buflen < *olen )
rahul_dahiya 0:fb8047b156bb 489 return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
rahul_dahiya 0:fb8047b156bb 490
rahul_dahiya 0:fb8047b156bb 491 buf[0] = 0x02 + mbedtls_mpi_get_bit( &P->Y, 0 );
rahul_dahiya 0:fb8047b156bb 492 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &P->X, buf + 1, plen ) );
rahul_dahiya 0:fb8047b156bb 493 }
rahul_dahiya 0:fb8047b156bb 494
rahul_dahiya 0:fb8047b156bb 495 cleanup:
rahul_dahiya 0:fb8047b156bb 496 return( ret );
rahul_dahiya 0:fb8047b156bb 497 }
rahul_dahiya 0:fb8047b156bb 498
rahul_dahiya 0:fb8047b156bb 499 /*
rahul_dahiya 0:fb8047b156bb 500 * Import a point from unsigned binary data (SEC1 2.3.4)
rahul_dahiya 0:fb8047b156bb 501 */
rahul_dahiya 0:fb8047b156bb 502 int mbedtls_ecp_point_read_binary( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
rahul_dahiya 0:fb8047b156bb 503 const unsigned char *buf, size_t ilen )
rahul_dahiya 0:fb8047b156bb 504 {
rahul_dahiya 0:fb8047b156bb 505 int ret;
rahul_dahiya 0:fb8047b156bb 506 size_t plen;
rahul_dahiya 0:fb8047b156bb 507
rahul_dahiya 0:fb8047b156bb 508 if( ilen < 1 )
rahul_dahiya 0:fb8047b156bb 509 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 510
rahul_dahiya 0:fb8047b156bb 511 if( buf[0] == 0x00 )
rahul_dahiya 0:fb8047b156bb 512 {
rahul_dahiya 0:fb8047b156bb 513 if( ilen == 1 )
rahul_dahiya 0:fb8047b156bb 514 return( mbedtls_ecp_set_zero( pt ) );
rahul_dahiya 0:fb8047b156bb 515 else
rahul_dahiya 0:fb8047b156bb 516 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 517 }
rahul_dahiya 0:fb8047b156bb 518
rahul_dahiya 0:fb8047b156bb 519 plen = mbedtls_mpi_size( &grp->P );
rahul_dahiya 0:fb8047b156bb 520
rahul_dahiya 0:fb8047b156bb 521 if( buf[0] != 0x04 )
rahul_dahiya 0:fb8047b156bb 522 return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
rahul_dahiya 0:fb8047b156bb 523
rahul_dahiya 0:fb8047b156bb 524 if( ilen != 2 * plen + 1 )
rahul_dahiya 0:fb8047b156bb 525 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 526
rahul_dahiya 0:fb8047b156bb 527 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &pt->X, buf + 1, plen ) );
rahul_dahiya 0:fb8047b156bb 528 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &pt->Y, buf + 1 + plen, plen ) );
rahul_dahiya 0:fb8047b156bb 529 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->Z, 1 ) );
rahul_dahiya 0:fb8047b156bb 530
rahul_dahiya 0:fb8047b156bb 531 cleanup:
rahul_dahiya 0:fb8047b156bb 532 return( ret );
rahul_dahiya 0:fb8047b156bb 533 }
rahul_dahiya 0:fb8047b156bb 534
rahul_dahiya 0:fb8047b156bb 535 /*
rahul_dahiya 0:fb8047b156bb 536 * Import a point from a TLS ECPoint record (RFC 4492)
rahul_dahiya 0:fb8047b156bb 537 * struct {
rahul_dahiya 0:fb8047b156bb 538 * opaque point <1..2^8-1>;
rahul_dahiya 0:fb8047b156bb 539 * } ECPoint;
rahul_dahiya 0:fb8047b156bb 540 */
rahul_dahiya 0:fb8047b156bb 541 int mbedtls_ecp_tls_read_point( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
rahul_dahiya 0:fb8047b156bb 542 const unsigned char **buf, size_t buf_len )
rahul_dahiya 0:fb8047b156bb 543 {
rahul_dahiya 0:fb8047b156bb 544 unsigned char data_len;
rahul_dahiya 0:fb8047b156bb 545 const unsigned char *buf_start;
rahul_dahiya 0:fb8047b156bb 546
rahul_dahiya 0:fb8047b156bb 547 /*
rahul_dahiya 0:fb8047b156bb 548 * We must have at least two bytes (1 for length, at least one for data)
rahul_dahiya 0:fb8047b156bb 549 */
rahul_dahiya 0:fb8047b156bb 550 if( buf_len < 2 )
rahul_dahiya 0:fb8047b156bb 551 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 552
rahul_dahiya 0:fb8047b156bb 553 data_len = *(*buf)++;
rahul_dahiya 0:fb8047b156bb 554 if( data_len < 1 || data_len > buf_len - 1 )
rahul_dahiya 0:fb8047b156bb 555 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 556
rahul_dahiya 0:fb8047b156bb 557 /*
rahul_dahiya 0:fb8047b156bb 558 * Save buffer start for read_binary and update buf
rahul_dahiya 0:fb8047b156bb 559 */
rahul_dahiya 0:fb8047b156bb 560 buf_start = *buf;
rahul_dahiya 0:fb8047b156bb 561 *buf += data_len;
rahul_dahiya 0:fb8047b156bb 562
rahul_dahiya 0:fb8047b156bb 563 return mbedtls_ecp_point_read_binary( grp, pt, buf_start, data_len );
rahul_dahiya 0:fb8047b156bb 564 }
rahul_dahiya 0:fb8047b156bb 565
rahul_dahiya 0:fb8047b156bb 566 /*
rahul_dahiya 0:fb8047b156bb 567 * Export a point as a TLS ECPoint record (RFC 4492)
rahul_dahiya 0:fb8047b156bb 568 * struct {
rahul_dahiya 0:fb8047b156bb 569 * opaque point <1..2^8-1>;
rahul_dahiya 0:fb8047b156bb 570 * } ECPoint;
rahul_dahiya 0:fb8047b156bb 571 */
rahul_dahiya 0:fb8047b156bb 572 int mbedtls_ecp_tls_write_point( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt,
rahul_dahiya 0:fb8047b156bb 573 int format, size_t *olen,
rahul_dahiya 0:fb8047b156bb 574 unsigned char *buf, size_t blen )
rahul_dahiya 0:fb8047b156bb 575 {
rahul_dahiya 0:fb8047b156bb 576 int ret;
rahul_dahiya 0:fb8047b156bb 577
rahul_dahiya 0:fb8047b156bb 578 /*
rahul_dahiya 0:fb8047b156bb 579 * buffer length must be at least one, for our length byte
rahul_dahiya 0:fb8047b156bb 580 */
rahul_dahiya 0:fb8047b156bb 581 if( blen < 1 )
rahul_dahiya 0:fb8047b156bb 582 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 583
rahul_dahiya 0:fb8047b156bb 584 if( ( ret = mbedtls_ecp_point_write_binary( grp, pt, format,
rahul_dahiya 0:fb8047b156bb 585 olen, buf + 1, blen - 1) ) != 0 )
rahul_dahiya 0:fb8047b156bb 586 return( ret );
rahul_dahiya 0:fb8047b156bb 587
rahul_dahiya 0:fb8047b156bb 588 /*
rahul_dahiya 0:fb8047b156bb 589 * write length to the first byte and update total length
rahul_dahiya 0:fb8047b156bb 590 */
rahul_dahiya 0:fb8047b156bb 591 buf[0] = (unsigned char) *olen;
rahul_dahiya 0:fb8047b156bb 592 ++*olen;
rahul_dahiya 0:fb8047b156bb 593
rahul_dahiya 0:fb8047b156bb 594 return( 0 );
rahul_dahiya 0:fb8047b156bb 595 }
rahul_dahiya 0:fb8047b156bb 596
rahul_dahiya 0:fb8047b156bb 597 /*
rahul_dahiya 0:fb8047b156bb 598 * Set a group from an ECParameters record (RFC 4492)
rahul_dahiya 0:fb8047b156bb 599 */
rahul_dahiya 0:fb8047b156bb 600 int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp, const unsigned char **buf, size_t len )
rahul_dahiya 0:fb8047b156bb 601 {
rahul_dahiya 0:fb8047b156bb 602 uint16_t tls_id;
rahul_dahiya 0:fb8047b156bb 603 const mbedtls_ecp_curve_info *curve_info;
rahul_dahiya 0:fb8047b156bb 604
rahul_dahiya 0:fb8047b156bb 605 /*
rahul_dahiya 0:fb8047b156bb 606 * We expect at least three bytes (see below)
rahul_dahiya 0:fb8047b156bb 607 */
rahul_dahiya 0:fb8047b156bb 608 if( len < 3 )
rahul_dahiya 0:fb8047b156bb 609 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 610
rahul_dahiya 0:fb8047b156bb 611 /*
rahul_dahiya 0:fb8047b156bb 612 * First byte is curve_type; only named_curve is handled
rahul_dahiya 0:fb8047b156bb 613 */
rahul_dahiya 0:fb8047b156bb 614 if( *(*buf)++ != MBEDTLS_ECP_TLS_NAMED_CURVE )
rahul_dahiya 0:fb8047b156bb 615 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 616
rahul_dahiya 0:fb8047b156bb 617 /*
rahul_dahiya 0:fb8047b156bb 618 * Next two bytes are the namedcurve value
rahul_dahiya 0:fb8047b156bb 619 */
rahul_dahiya 0:fb8047b156bb 620 tls_id = *(*buf)++;
rahul_dahiya 0:fb8047b156bb 621 tls_id <<= 8;
rahul_dahiya 0:fb8047b156bb 622 tls_id |= *(*buf)++;
rahul_dahiya 0:fb8047b156bb 623
rahul_dahiya 0:fb8047b156bb 624 if( ( curve_info = mbedtls_ecp_curve_info_from_tls_id( tls_id ) ) == NULL )
rahul_dahiya 0:fb8047b156bb 625 return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
rahul_dahiya 0:fb8047b156bb 626
rahul_dahiya 0:fb8047b156bb 627 return mbedtls_ecp_group_load( grp, curve_info->grp_id );
rahul_dahiya 0:fb8047b156bb 628 }
rahul_dahiya 0:fb8047b156bb 629
rahul_dahiya 0:fb8047b156bb 630 /*
rahul_dahiya 0:fb8047b156bb 631 * Write the ECParameters record corresponding to a group (RFC 4492)
rahul_dahiya 0:fb8047b156bb 632 */
rahul_dahiya 0:fb8047b156bb 633 int mbedtls_ecp_tls_write_group( const mbedtls_ecp_group *grp, size_t *olen,
rahul_dahiya 0:fb8047b156bb 634 unsigned char *buf, size_t blen )
rahul_dahiya 0:fb8047b156bb 635 {
rahul_dahiya 0:fb8047b156bb 636 const mbedtls_ecp_curve_info *curve_info;
rahul_dahiya 0:fb8047b156bb 637
rahul_dahiya 0:fb8047b156bb 638 if( ( curve_info = mbedtls_ecp_curve_info_from_grp_id( grp->id ) ) == NULL )
rahul_dahiya 0:fb8047b156bb 639 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 640
rahul_dahiya 0:fb8047b156bb 641 /*
rahul_dahiya 0:fb8047b156bb 642 * We are going to write 3 bytes (see below)
rahul_dahiya 0:fb8047b156bb 643 */
rahul_dahiya 0:fb8047b156bb 644 *olen = 3;
rahul_dahiya 0:fb8047b156bb 645 if( blen < *olen )
rahul_dahiya 0:fb8047b156bb 646 return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
rahul_dahiya 0:fb8047b156bb 647
rahul_dahiya 0:fb8047b156bb 648 /*
rahul_dahiya 0:fb8047b156bb 649 * First byte is curve_type, always named_curve
rahul_dahiya 0:fb8047b156bb 650 */
rahul_dahiya 0:fb8047b156bb 651 *buf++ = MBEDTLS_ECP_TLS_NAMED_CURVE;
rahul_dahiya 0:fb8047b156bb 652
rahul_dahiya 0:fb8047b156bb 653 /*
rahul_dahiya 0:fb8047b156bb 654 * Next two bytes are the namedcurve value
rahul_dahiya 0:fb8047b156bb 655 */
rahul_dahiya 0:fb8047b156bb 656 buf[0] = curve_info->tls_id >> 8;
rahul_dahiya 0:fb8047b156bb 657 buf[1] = curve_info->tls_id & 0xFF;
rahul_dahiya 0:fb8047b156bb 658
rahul_dahiya 0:fb8047b156bb 659 return( 0 );
rahul_dahiya 0:fb8047b156bb 660 }
rahul_dahiya 0:fb8047b156bb 661
rahul_dahiya 0:fb8047b156bb 662 /*
rahul_dahiya 0:fb8047b156bb 663 * Wrapper around fast quasi-modp functions, with fall-back to mbedtls_mpi_mod_mpi.
rahul_dahiya 0:fb8047b156bb 664 * See the documentation of struct mbedtls_ecp_group.
rahul_dahiya 0:fb8047b156bb 665 *
rahul_dahiya 0:fb8047b156bb 666 * This function is in the critial loop for mbedtls_ecp_mul, so pay attention to perf.
rahul_dahiya 0:fb8047b156bb 667 */
rahul_dahiya 0:fb8047b156bb 668 static int ecp_modp( mbedtls_mpi *N, const mbedtls_ecp_group *grp )
rahul_dahiya 0:fb8047b156bb 669 {
rahul_dahiya 0:fb8047b156bb 670 int ret;
rahul_dahiya 0:fb8047b156bb 671
rahul_dahiya 0:fb8047b156bb 672 if( grp->modp == NULL )
rahul_dahiya 0:fb8047b156bb 673 return( mbedtls_mpi_mod_mpi( N, N, &grp->P ) );
rahul_dahiya 0:fb8047b156bb 674
rahul_dahiya 0:fb8047b156bb 675 /* N->s < 0 is a much faster test, which fails only if N is 0 */
rahul_dahiya 0:fb8047b156bb 676 if( ( N->s < 0 && mbedtls_mpi_cmp_int( N, 0 ) != 0 ) ||
rahul_dahiya 0:fb8047b156bb 677 mbedtls_mpi_bitlen( N ) > 2 * grp->pbits )
rahul_dahiya 0:fb8047b156bb 678 {
rahul_dahiya 0:fb8047b156bb 679 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 680 }
rahul_dahiya 0:fb8047b156bb 681
rahul_dahiya 0:fb8047b156bb 682 MBEDTLS_MPI_CHK( grp->modp( N ) );
rahul_dahiya 0:fb8047b156bb 683
rahul_dahiya 0:fb8047b156bb 684 /* N->s < 0 is a much faster test, which fails only if N is 0 */
rahul_dahiya 0:fb8047b156bb 685 while( N->s < 0 && mbedtls_mpi_cmp_int( N, 0 ) != 0 )
rahul_dahiya 0:fb8047b156bb 686 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( N, N, &grp->P ) );
rahul_dahiya 0:fb8047b156bb 687
rahul_dahiya 0:fb8047b156bb 688 while( mbedtls_mpi_cmp_mpi( N, &grp->P ) >= 0 )
rahul_dahiya 0:fb8047b156bb 689 /* we known P, N and the result are positive */
rahul_dahiya 0:fb8047b156bb 690 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( N, N, &grp->P ) );
rahul_dahiya 0:fb8047b156bb 691
rahul_dahiya 0:fb8047b156bb 692 cleanup:
rahul_dahiya 0:fb8047b156bb 693 return( ret );
rahul_dahiya 0:fb8047b156bb 694 }
rahul_dahiya 0:fb8047b156bb 695
rahul_dahiya 0:fb8047b156bb 696 /*
rahul_dahiya 0:fb8047b156bb 697 * Fast mod-p functions expect their argument to be in the 0..p^2 range.
rahul_dahiya 0:fb8047b156bb 698 *
rahul_dahiya 0:fb8047b156bb 699 * In order to guarantee that, we need to ensure that operands of
rahul_dahiya 0:fb8047b156bb 700 * mbedtls_mpi_mul_mpi are in the 0..p range. So, after each operation we will
rahul_dahiya 0:fb8047b156bb 701 * bring the result back to this range.
rahul_dahiya 0:fb8047b156bb 702 *
rahul_dahiya 0:fb8047b156bb 703 * The following macros are shortcuts for doing that.
rahul_dahiya 0:fb8047b156bb 704 */
rahul_dahiya 0:fb8047b156bb 705
rahul_dahiya 0:fb8047b156bb 706 /*
rahul_dahiya 0:fb8047b156bb 707 * Reduce a mbedtls_mpi mod p in-place, general case, to use after mbedtls_mpi_mul_mpi
rahul_dahiya 0:fb8047b156bb 708 */
rahul_dahiya 0:fb8047b156bb 709 #if defined(MBEDTLS_SELF_TEST)
rahul_dahiya 0:fb8047b156bb 710 #define INC_MUL_COUNT mul_count++;
rahul_dahiya 0:fb8047b156bb 711 #else
rahul_dahiya 0:fb8047b156bb 712 #define INC_MUL_COUNT
rahul_dahiya 0:fb8047b156bb 713 #endif
rahul_dahiya 0:fb8047b156bb 714
rahul_dahiya 0:fb8047b156bb 715 #define MOD_MUL( N ) do { MBEDTLS_MPI_CHK( ecp_modp( &N, grp ) ); INC_MUL_COUNT } \
rahul_dahiya 0:fb8047b156bb 716 while( 0 )
rahul_dahiya 0:fb8047b156bb 717
rahul_dahiya 0:fb8047b156bb 718 /*
rahul_dahiya 0:fb8047b156bb 719 * Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_sub_mpi
rahul_dahiya 0:fb8047b156bb 720 * N->s < 0 is a very fast test, which fails only if N is 0
rahul_dahiya 0:fb8047b156bb 721 */
rahul_dahiya 0:fb8047b156bb 722 #define MOD_SUB( N ) \
rahul_dahiya 0:fb8047b156bb 723 while( N.s < 0 && mbedtls_mpi_cmp_int( &N, 0 ) != 0 ) \
rahul_dahiya 0:fb8047b156bb 724 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &N, &N, &grp->P ) )
rahul_dahiya 0:fb8047b156bb 725
rahul_dahiya 0:fb8047b156bb 726 /*
rahul_dahiya 0:fb8047b156bb 727 * Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_add_mpi and mbedtls_mpi_mul_int.
rahul_dahiya 0:fb8047b156bb 728 * We known P, N and the result are positive, so sub_abs is correct, and
rahul_dahiya 0:fb8047b156bb 729 * a bit faster.
rahul_dahiya 0:fb8047b156bb 730 */
rahul_dahiya 0:fb8047b156bb 731 #define MOD_ADD( N ) \
rahul_dahiya 0:fb8047b156bb 732 while( mbedtls_mpi_cmp_mpi( &N, &grp->P ) >= 0 ) \
rahul_dahiya 0:fb8047b156bb 733 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &N, &N, &grp->P ) )
rahul_dahiya 0:fb8047b156bb 734
rahul_dahiya 0:fb8047b156bb 735 #if defined(ECP_SHORTWEIERSTRASS)
rahul_dahiya 0:fb8047b156bb 736 /*
rahul_dahiya 0:fb8047b156bb 737 * For curves in short Weierstrass form, we do all the internal operations in
rahul_dahiya 0:fb8047b156bb 738 * Jacobian coordinates.
rahul_dahiya 0:fb8047b156bb 739 *
rahul_dahiya 0:fb8047b156bb 740 * For multiplication, we'll use a comb method with coutermeasueres against
rahul_dahiya 0:fb8047b156bb 741 * SPA, hence timing attacks.
rahul_dahiya 0:fb8047b156bb 742 */
rahul_dahiya 0:fb8047b156bb 743
rahul_dahiya 0:fb8047b156bb 744 /*
rahul_dahiya 0:fb8047b156bb 745 * Normalize jacobian coordinates so that Z == 0 || Z == 1 (GECC 3.2.1)
rahul_dahiya 0:fb8047b156bb 746 * Cost: 1N := 1I + 3M + 1S
rahul_dahiya 0:fb8047b156bb 747 */
rahul_dahiya 0:fb8047b156bb 748 static int ecp_normalize_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 749 {
rahul_dahiya 0:fb8047b156bb 750 int ret;
rahul_dahiya 0:fb8047b156bb 751 mbedtls_mpi Zi, ZZi;
rahul_dahiya 0:fb8047b156bb 752
rahul_dahiya 0:fb8047b156bb 753 if( mbedtls_mpi_cmp_int( &pt->Z, 0 ) == 0 )
rahul_dahiya 0:fb8047b156bb 754 return( 0 );
rahul_dahiya 0:fb8047b156bb 755
rahul_dahiya 0:fb8047b156bb 756 #if defined(MBEDTLS_ECP_NORMALIZE_JAC_ALT)
rahul_dahiya 0:fb8047b156bb 757 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 758 {
rahul_dahiya 0:fb8047b156bb 759 return mbedtls_internal_ecp_normalize_jac( grp, pt );
rahul_dahiya 0:fb8047b156bb 760 }
rahul_dahiya 0:fb8047b156bb 761 #endif /* MBEDTLS_ECP_NORMALIZE_JAC_ALT */
rahul_dahiya 0:fb8047b156bb 762 mbedtls_mpi_init( &Zi ); mbedtls_mpi_init( &ZZi );
rahul_dahiya 0:fb8047b156bb 763
rahul_dahiya 0:fb8047b156bb 764 /*
rahul_dahiya 0:fb8047b156bb 765 * X = X / Z^2 mod p
rahul_dahiya 0:fb8047b156bb 766 */
rahul_dahiya 0:fb8047b156bb 767 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &Zi, &pt->Z, &grp->P ) );
rahul_dahiya 0:fb8047b156bb 768 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ZZi, &Zi, &Zi ) ); MOD_MUL( ZZi );
rahul_dahiya 0:fb8047b156bb 769 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &pt->X, &pt->X, &ZZi ) ); MOD_MUL( pt->X );
rahul_dahiya 0:fb8047b156bb 770
rahul_dahiya 0:fb8047b156bb 771 /*
rahul_dahiya 0:fb8047b156bb 772 * Y = Y / Z^3 mod p
rahul_dahiya 0:fb8047b156bb 773 */
rahul_dahiya 0:fb8047b156bb 774 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &pt->Y, &pt->Y, &ZZi ) ); MOD_MUL( pt->Y );
rahul_dahiya 0:fb8047b156bb 775 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &pt->Y, &pt->Y, &Zi ) ); MOD_MUL( pt->Y );
rahul_dahiya 0:fb8047b156bb 776
rahul_dahiya 0:fb8047b156bb 777 /*
rahul_dahiya 0:fb8047b156bb 778 * Z = 1
rahul_dahiya 0:fb8047b156bb 779 */
rahul_dahiya 0:fb8047b156bb 780 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &pt->Z, 1 ) );
rahul_dahiya 0:fb8047b156bb 781
rahul_dahiya 0:fb8047b156bb 782 cleanup:
rahul_dahiya 0:fb8047b156bb 783
rahul_dahiya 0:fb8047b156bb 784 mbedtls_mpi_free( &Zi ); mbedtls_mpi_free( &ZZi );
rahul_dahiya 0:fb8047b156bb 785
rahul_dahiya 0:fb8047b156bb 786 return( ret );
rahul_dahiya 0:fb8047b156bb 787 }
rahul_dahiya 0:fb8047b156bb 788
rahul_dahiya 0:fb8047b156bb 789 /*
rahul_dahiya 0:fb8047b156bb 790 * Normalize jacobian coordinates of an array of (pointers to) points,
rahul_dahiya 0:fb8047b156bb 791 * using Montgomery's trick to perform only one inversion mod P.
rahul_dahiya 0:fb8047b156bb 792 * (See for example Cohen's "A Course in Computational Algebraic Number
rahul_dahiya 0:fb8047b156bb 793 * Theory", Algorithm 10.3.4.)
rahul_dahiya 0:fb8047b156bb 794 *
rahul_dahiya 0:fb8047b156bb 795 * Warning: fails (returning an error) if one of the points is zero!
rahul_dahiya 0:fb8047b156bb 796 * This should never happen, see choice of w in ecp_mul_comb().
rahul_dahiya 0:fb8047b156bb 797 *
rahul_dahiya 0:fb8047b156bb 798 * Cost: 1N(t) := 1I + (6t - 3)M + 1S
rahul_dahiya 0:fb8047b156bb 799 */
rahul_dahiya 0:fb8047b156bb 800 static int ecp_normalize_jac_many( const mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 801 mbedtls_ecp_point *T[], size_t t_len )
rahul_dahiya 0:fb8047b156bb 802 {
rahul_dahiya 0:fb8047b156bb 803 int ret;
rahul_dahiya 0:fb8047b156bb 804 size_t i;
rahul_dahiya 0:fb8047b156bb 805 mbedtls_mpi *c, u, Zi, ZZi;
rahul_dahiya 0:fb8047b156bb 806
rahul_dahiya 0:fb8047b156bb 807 if( t_len < 2 )
rahul_dahiya 0:fb8047b156bb 808 return( ecp_normalize_jac( grp, *T ) );
rahul_dahiya 0:fb8047b156bb 809
rahul_dahiya 0:fb8047b156bb 810 #if defined(MBEDTLS_ECP_NORMALIZE_JAC_MANY_ALT)
rahul_dahiya 0:fb8047b156bb 811 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 812 {
rahul_dahiya 0:fb8047b156bb 813 return mbedtls_internal_ecp_normalize_jac_many(grp, T, t_len);
rahul_dahiya 0:fb8047b156bb 814 }
rahul_dahiya 0:fb8047b156bb 815 #endif
rahul_dahiya 0:fb8047b156bb 816
rahul_dahiya 0:fb8047b156bb 817 if( ( c = mbedtls_calloc( t_len, sizeof( mbedtls_mpi ) ) ) == NULL )
rahul_dahiya 0:fb8047b156bb 818 return( MBEDTLS_ERR_ECP_ALLOC_FAILED );
rahul_dahiya 0:fb8047b156bb 819
rahul_dahiya 0:fb8047b156bb 820 mbedtls_mpi_init( &u ); mbedtls_mpi_init( &Zi ); mbedtls_mpi_init( &ZZi );
rahul_dahiya 0:fb8047b156bb 821
rahul_dahiya 0:fb8047b156bb 822 /*
rahul_dahiya 0:fb8047b156bb 823 * c[i] = Z_0 * ... * Z_i
rahul_dahiya 0:fb8047b156bb 824 */
rahul_dahiya 0:fb8047b156bb 825 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &c[0], &T[0]->Z ) );
rahul_dahiya 0:fb8047b156bb 826 for( i = 1; i < t_len; i++ )
rahul_dahiya 0:fb8047b156bb 827 {
rahul_dahiya 0:fb8047b156bb 828 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &c[i], &c[i-1], &T[i]->Z ) );
rahul_dahiya 0:fb8047b156bb 829 MOD_MUL( c[i] );
rahul_dahiya 0:fb8047b156bb 830 }
rahul_dahiya 0:fb8047b156bb 831
rahul_dahiya 0:fb8047b156bb 832 /*
rahul_dahiya 0:fb8047b156bb 833 * u = 1 / (Z_0 * ... * Z_n) mod P
rahul_dahiya 0:fb8047b156bb 834 */
rahul_dahiya 0:fb8047b156bb 835 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &u, &c[t_len-1], &grp->P ) );
rahul_dahiya 0:fb8047b156bb 836
rahul_dahiya 0:fb8047b156bb 837 for( i = t_len - 1; ; i-- )
rahul_dahiya 0:fb8047b156bb 838 {
rahul_dahiya 0:fb8047b156bb 839 /*
rahul_dahiya 0:fb8047b156bb 840 * Zi = 1 / Z_i mod p
rahul_dahiya 0:fb8047b156bb 841 * u = 1 / (Z_0 * ... * Z_i) mod P
rahul_dahiya 0:fb8047b156bb 842 */
rahul_dahiya 0:fb8047b156bb 843 if( i == 0 ) {
rahul_dahiya 0:fb8047b156bb 844 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &Zi, &u ) );
rahul_dahiya 0:fb8047b156bb 845 }
rahul_dahiya 0:fb8047b156bb 846 else
rahul_dahiya 0:fb8047b156bb 847 {
rahul_dahiya 0:fb8047b156bb 848 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &Zi, &u, &c[i-1] ) ); MOD_MUL( Zi );
rahul_dahiya 0:fb8047b156bb 849 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &u, &u, &T[i]->Z ) ); MOD_MUL( u );
rahul_dahiya 0:fb8047b156bb 850 }
rahul_dahiya 0:fb8047b156bb 851
rahul_dahiya 0:fb8047b156bb 852 /*
rahul_dahiya 0:fb8047b156bb 853 * proceed as in normalize()
rahul_dahiya 0:fb8047b156bb 854 */
rahul_dahiya 0:fb8047b156bb 855 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ZZi, &Zi, &Zi ) ); MOD_MUL( ZZi );
rahul_dahiya 0:fb8047b156bb 856 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T[i]->X, &T[i]->X, &ZZi ) ); MOD_MUL( T[i]->X );
rahul_dahiya 0:fb8047b156bb 857 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T[i]->Y, &T[i]->Y, &ZZi ) ); MOD_MUL( T[i]->Y );
rahul_dahiya 0:fb8047b156bb 858 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T[i]->Y, &T[i]->Y, &Zi ) ); MOD_MUL( T[i]->Y );
rahul_dahiya 0:fb8047b156bb 859
rahul_dahiya 0:fb8047b156bb 860 /*
rahul_dahiya 0:fb8047b156bb 861 * Post-precessing: reclaim some memory by shrinking coordinates
rahul_dahiya 0:fb8047b156bb 862 * - not storing Z (always 1)
rahul_dahiya 0:fb8047b156bb 863 * - shrinking other coordinates, but still keeping the same number of
rahul_dahiya 0:fb8047b156bb 864 * limbs as P, as otherwise it will too likely be regrown too fast.
rahul_dahiya 0:fb8047b156bb 865 */
rahul_dahiya 0:fb8047b156bb 866 MBEDTLS_MPI_CHK( mbedtls_mpi_shrink( &T[i]->X, grp->P.n ) );
rahul_dahiya 0:fb8047b156bb 867 MBEDTLS_MPI_CHK( mbedtls_mpi_shrink( &T[i]->Y, grp->P.n ) );
rahul_dahiya 0:fb8047b156bb 868 mbedtls_mpi_free( &T[i]->Z );
rahul_dahiya 0:fb8047b156bb 869
rahul_dahiya 0:fb8047b156bb 870 if( i == 0 )
rahul_dahiya 0:fb8047b156bb 871 break;
rahul_dahiya 0:fb8047b156bb 872 }
rahul_dahiya 0:fb8047b156bb 873
rahul_dahiya 0:fb8047b156bb 874 cleanup:
rahul_dahiya 0:fb8047b156bb 875
rahul_dahiya 0:fb8047b156bb 876 mbedtls_mpi_free( &u ); mbedtls_mpi_free( &Zi ); mbedtls_mpi_free( &ZZi );
rahul_dahiya 0:fb8047b156bb 877 for( i = 0; i < t_len; i++ )
rahul_dahiya 0:fb8047b156bb 878 mbedtls_mpi_free( &c[i] );
rahul_dahiya 0:fb8047b156bb 879 mbedtls_free( c );
rahul_dahiya 0:fb8047b156bb 880
rahul_dahiya 0:fb8047b156bb 881 return( ret );
rahul_dahiya 0:fb8047b156bb 882 }
rahul_dahiya 0:fb8047b156bb 883
rahul_dahiya 0:fb8047b156bb 884 /*
rahul_dahiya 0:fb8047b156bb 885 * Conditional point inversion: Q -> -Q = (Q.X, -Q.Y, Q.Z) without leak.
rahul_dahiya 0:fb8047b156bb 886 * "inv" must be 0 (don't invert) or 1 (invert) or the result will be invalid
rahul_dahiya 0:fb8047b156bb 887 */
rahul_dahiya 0:fb8047b156bb 888 static int ecp_safe_invert_jac( const mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 889 mbedtls_ecp_point *Q,
rahul_dahiya 0:fb8047b156bb 890 unsigned char inv )
rahul_dahiya 0:fb8047b156bb 891 {
rahul_dahiya 0:fb8047b156bb 892 int ret;
rahul_dahiya 0:fb8047b156bb 893 unsigned char nonzero;
rahul_dahiya 0:fb8047b156bb 894 mbedtls_mpi mQY;
rahul_dahiya 0:fb8047b156bb 895
rahul_dahiya 0:fb8047b156bb 896 mbedtls_mpi_init( &mQY );
rahul_dahiya 0:fb8047b156bb 897
rahul_dahiya 0:fb8047b156bb 898 /* Use the fact that -Q.Y mod P = P - Q.Y unless Q.Y == 0 */
rahul_dahiya 0:fb8047b156bb 899 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &mQY, &grp->P, &Q->Y ) );
rahul_dahiya 0:fb8047b156bb 900 nonzero = mbedtls_mpi_cmp_int( &Q->Y, 0 ) != 0;
rahul_dahiya 0:fb8047b156bb 901 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &Q->Y, &mQY, inv & nonzero ) );
rahul_dahiya 0:fb8047b156bb 902
rahul_dahiya 0:fb8047b156bb 903 cleanup:
rahul_dahiya 0:fb8047b156bb 904 mbedtls_mpi_free( &mQY );
rahul_dahiya 0:fb8047b156bb 905
rahul_dahiya 0:fb8047b156bb 906 return( ret );
rahul_dahiya 0:fb8047b156bb 907 }
rahul_dahiya 0:fb8047b156bb 908
rahul_dahiya 0:fb8047b156bb 909 /*
rahul_dahiya 0:fb8047b156bb 910 * Point doubling R = 2 P, Jacobian coordinates
rahul_dahiya 0:fb8047b156bb 911 *
rahul_dahiya 0:fb8047b156bb 912 * Based on http://www.hyperelliptic.org/EFD/g1p/auto-shortw-jacobian.html#doubling-dbl-1998-cmo-2 .
rahul_dahiya 0:fb8047b156bb 913 *
rahul_dahiya 0:fb8047b156bb 914 * We follow the variable naming fairly closely. The formula variations that trade a MUL for a SQR
rahul_dahiya 0:fb8047b156bb 915 * (plus a few ADDs) aren't useful as our bignum implementation doesn't distinguish squaring.
rahul_dahiya 0:fb8047b156bb 916 *
rahul_dahiya 0:fb8047b156bb 917 * Standard optimizations are applied when curve parameter A is one of { 0, -3 }.
rahul_dahiya 0:fb8047b156bb 918 *
rahul_dahiya 0:fb8047b156bb 919 * Cost: 1D := 3M + 4S (A == 0)
rahul_dahiya 0:fb8047b156bb 920 * 4M + 4S (A == -3)
rahul_dahiya 0:fb8047b156bb 921 * 3M + 6S + 1a otherwise
rahul_dahiya 0:fb8047b156bb 922 */
rahul_dahiya 0:fb8047b156bb 923 static int ecp_double_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 924 const mbedtls_ecp_point *P )
rahul_dahiya 0:fb8047b156bb 925 {
rahul_dahiya 0:fb8047b156bb 926 int ret;
rahul_dahiya 0:fb8047b156bb 927 mbedtls_mpi M, S, T, U;
rahul_dahiya 0:fb8047b156bb 928
rahul_dahiya 0:fb8047b156bb 929 #if defined(MBEDTLS_SELF_TEST)
rahul_dahiya 0:fb8047b156bb 930 dbl_count++;
rahul_dahiya 0:fb8047b156bb 931 #endif
rahul_dahiya 0:fb8047b156bb 932
rahul_dahiya 0:fb8047b156bb 933 #if defined(MBEDTLS_ECP_DOUBLE_JAC_ALT)
rahul_dahiya 0:fb8047b156bb 934 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 935 {
rahul_dahiya 0:fb8047b156bb 936 return mbedtls_internal_ecp_double_jac( grp, R, P );
rahul_dahiya 0:fb8047b156bb 937 }
rahul_dahiya 0:fb8047b156bb 938 #endif /* MBEDTLS_ECP_DOUBLE_JAC_ALT */
rahul_dahiya 0:fb8047b156bb 939
rahul_dahiya 0:fb8047b156bb 940 mbedtls_mpi_init( &M ); mbedtls_mpi_init( &S ); mbedtls_mpi_init( &T ); mbedtls_mpi_init( &U );
rahul_dahiya 0:fb8047b156bb 941
rahul_dahiya 0:fb8047b156bb 942 /* Special case for A = -3 */
rahul_dahiya 0:fb8047b156bb 943 if( grp->A.p == NULL )
rahul_dahiya 0:fb8047b156bb 944 {
rahul_dahiya 0:fb8047b156bb 945 /* M = 3(X + Z^2)(X - Z^2) */
rahul_dahiya 0:fb8047b156bb 946 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &P->Z, &P->Z ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 947 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &T, &P->X, &S ) ); MOD_ADD( T );
rahul_dahiya 0:fb8047b156bb 948 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &U, &P->X, &S ) ); MOD_SUB( U );
rahul_dahiya 0:fb8047b156bb 949 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &T, &U ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 950 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &M, &S, 3 ) ); MOD_ADD( M );
rahul_dahiya 0:fb8047b156bb 951 }
rahul_dahiya 0:fb8047b156bb 952 else
rahul_dahiya 0:fb8047b156bb 953 {
rahul_dahiya 0:fb8047b156bb 954 /* M = 3.X^2 */
rahul_dahiya 0:fb8047b156bb 955 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &P->X, &P->X ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 956 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &M, &S, 3 ) ); MOD_ADD( M );
rahul_dahiya 0:fb8047b156bb 957
rahul_dahiya 0:fb8047b156bb 958 /* Optimize away for "koblitz" curves with A = 0 */
rahul_dahiya 0:fb8047b156bb 959 if( mbedtls_mpi_cmp_int( &grp->A, 0 ) != 0 )
rahul_dahiya 0:fb8047b156bb 960 {
rahul_dahiya 0:fb8047b156bb 961 /* M += A.Z^4 */
rahul_dahiya 0:fb8047b156bb 962 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &P->Z, &P->Z ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 963 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &S, &S ) ); MOD_MUL( T );
rahul_dahiya 0:fb8047b156bb 964 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &T, &grp->A ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 965 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &M, &M, &S ) ); MOD_ADD( M );
rahul_dahiya 0:fb8047b156bb 966 }
rahul_dahiya 0:fb8047b156bb 967 }
rahul_dahiya 0:fb8047b156bb 968
rahul_dahiya 0:fb8047b156bb 969 /* S = 4.X.Y^2 */
rahul_dahiya 0:fb8047b156bb 970 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &P->Y, &P->Y ) ); MOD_MUL( T );
rahul_dahiya 0:fb8047b156bb 971 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &T, 1 ) ); MOD_ADD( T );
rahul_dahiya 0:fb8047b156bb 972 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &P->X, &T ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 973 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &S, 1 ) ); MOD_ADD( S );
rahul_dahiya 0:fb8047b156bb 974
rahul_dahiya 0:fb8047b156bb 975 /* U = 8.Y^4 */
rahul_dahiya 0:fb8047b156bb 976 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &U, &T, &T ) ); MOD_MUL( U );
rahul_dahiya 0:fb8047b156bb 977 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &U, 1 ) ); MOD_ADD( U );
rahul_dahiya 0:fb8047b156bb 978
rahul_dahiya 0:fb8047b156bb 979 /* T = M^2 - 2.S */
rahul_dahiya 0:fb8047b156bb 980 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &M, &M ) ); MOD_MUL( T );
rahul_dahiya 0:fb8047b156bb 981 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T, &T, &S ) ); MOD_SUB( T );
rahul_dahiya 0:fb8047b156bb 982 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T, &T, &S ) ); MOD_SUB( T );
rahul_dahiya 0:fb8047b156bb 983
rahul_dahiya 0:fb8047b156bb 984 /* S = M(S - T) - U */
rahul_dahiya 0:fb8047b156bb 985 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &S, &S, &T ) ); MOD_SUB( S );
rahul_dahiya 0:fb8047b156bb 986 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S, &S, &M ) ); MOD_MUL( S );
rahul_dahiya 0:fb8047b156bb 987 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &S, &S, &U ) ); MOD_SUB( S );
rahul_dahiya 0:fb8047b156bb 988
rahul_dahiya 0:fb8047b156bb 989 /* U = 2.Y.Z */
rahul_dahiya 0:fb8047b156bb 990 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &U, &P->Y, &P->Z ) ); MOD_MUL( U );
rahul_dahiya 0:fb8047b156bb 991 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_l( &U, 1 ) ); MOD_ADD( U );
rahul_dahiya 0:fb8047b156bb 992
rahul_dahiya 0:fb8047b156bb 993 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R->X, &T ) );
rahul_dahiya 0:fb8047b156bb 994 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R->Y, &S ) );
rahul_dahiya 0:fb8047b156bb 995 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R->Z, &U ) );
rahul_dahiya 0:fb8047b156bb 996
rahul_dahiya 0:fb8047b156bb 997 cleanup:
rahul_dahiya 0:fb8047b156bb 998 mbedtls_mpi_free( &M ); mbedtls_mpi_free( &S ); mbedtls_mpi_free( &T ); mbedtls_mpi_free( &U );
rahul_dahiya 0:fb8047b156bb 999
rahul_dahiya 0:fb8047b156bb 1000 return( ret );
rahul_dahiya 0:fb8047b156bb 1001 }
rahul_dahiya 0:fb8047b156bb 1002
rahul_dahiya 0:fb8047b156bb 1003 /*
rahul_dahiya 0:fb8047b156bb 1004 * Addition: R = P + Q, mixed affine-Jacobian coordinates (GECC 3.22)
rahul_dahiya 0:fb8047b156bb 1005 *
rahul_dahiya 0:fb8047b156bb 1006 * The coordinates of Q must be normalized (= affine),
rahul_dahiya 0:fb8047b156bb 1007 * but those of P don't need to. R is not normalized.
rahul_dahiya 0:fb8047b156bb 1008 *
rahul_dahiya 0:fb8047b156bb 1009 * Special cases: (1) P or Q is zero, (2) R is zero, (3) P == Q.
rahul_dahiya 0:fb8047b156bb 1010 * None of these cases can happen as intermediate step in ecp_mul_comb():
rahul_dahiya 0:fb8047b156bb 1011 * - at each step, P, Q and R are multiples of the base point, the factor
rahul_dahiya 0:fb8047b156bb 1012 * being less than its order, so none of them is zero;
rahul_dahiya 0:fb8047b156bb 1013 * - Q is an odd multiple of the base point, P an even multiple,
rahul_dahiya 0:fb8047b156bb 1014 * due to the choice of precomputed points in the modified comb method.
rahul_dahiya 0:fb8047b156bb 1015 * So branches for these cases do not leak secret information.
rahul_dahiya 0:fb8047b156bb 1016 *
rahul_dahiya 0:fb8047b156bb 1017 * We accept Q->Z being unset (saving memory in tables) as meaning 1.
rahul_dahiya 0:fb8047b156bb 1018 *
rahul_dahiya 0:fb8047b156bb 1019 * Cost: 1A := 8M + 3S
rahul_dahiya 0:fb8047b156bb 1020 */
rahul_dahiya 0:fb8047b156bb 1021 static int ecp_add_mixed( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1022 const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q )
rahul_dahiya 0:fb8047b156bb 1023 {
rahul_dahiya 0:fb8047b156bb 1024 int ret;
rahul_dahiya 0:fb8047b156bb 1025 mbedtls_mpi T1, T2, T3, T4, X, Y, Z;
rahul_dahiya 0:fb8047b156bb 1026
rahul_dahiya 0:fb8047b156bb 1027 #if defined(MBEDTLS_SELF_TEST)
rahul_dahiya 0:fb8047b156bb 1028 add_count++;
rahul_dahiya 0:fb8047b156bb 1029 #endif
rahul_dahiya 0:fb8047b156bb 1030
rahul_dahiya 0:fb8047b156bb 1031 #if defined(MBEDTLS_ECP_ADD_MIXED_ALT)
rahul_dahiya 0:fb8047b156bb 1032 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1033 {
rahul_dahiya 0:fb8047b156bb 1034 return mbedtls_internal_ecp_add_mixed( grp, R, P, Q );
rahul_dahiya 0:fb8047b156bb 1035 }
rahul_dahiya 0:fb8047b156bb 1036 #endif /* MBEDTLS_ECP_ADD_MIXED_ALT */
rahul_dahiya 0:fb8047b156bb 1037
rahul_dahiya 0:fb8047b156bb 1038 /*
rahul_dahiya 0:fb8047b156bb 1039 * Trivial cases: P == 0 or Q == 0 (case 1)
rahul_dahiya 0:fb8047b156bb 1040 */
rahul_dahiya 0:fb8047b156bb 1041 if( mbedtls_mpi_cmp_int( &P->Z, 0 ) == 0 )
rahul_dahiya 0:fb8047b156bb 1042 return( mbedtls_ecp_copy( R, Q ) );
rahul_dahiya 0:fb8047b156bb 1043
rahul_dahiya 0:fb8047b156bb 1044 if( Q->Z.p != NULL && mbedtls_mpi_cmp_int( &Q->Z, 0 ) == 0 )
rahul_dahiya 0:fb8047b156bb 1045 return( mbedtls_ecp_copy( R, P ) );
rahul_dahiya 0:fb8047b156bb 1046
rahul_dahiya 0:fb8047b156bb 1047 /*
rahul_dahiya 0:fb8047b156bb 1048 * Make sure Q coordinates are normalized
rahul_dahiya 0:fb8047b156bb 1049 */
rahul_dahiya 0:fb8047b156bb 1050 if( Q->Z.p != NULL && mbedtls_mpi_cmp_int( &Q->Z, 1 ) != 0 )
rahul_dahiya 0:fb8047b156bb 1051 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 1052
rahul_dahiya 0:fb8047b156bb 1053 mbedtls_mpi_init( &T1 ); mbedtls_mpi_init( &T2 ); mbedtls_mpi_init( &T3 ); mbedtls_mpi_init( &T4 );
rahul_dahiya 0:fb8047b156bb 1054 mbedtls_mpi_init( &X ); mbedtls_mpi_init( &Y ); mbedtls_mpi_init( &Z );
rahul_dahiya 0:fb8047b156bb 1055
rahul_dahiya 0:fb8047b156bb 1056 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T1, &P->Z, &P->Z ) ); MOD_MUL( T1 );
rahul_dahiya 0:fb8047b156bb 1057 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T2, &T1, &P->Z ) ); MOD_MUL( T2 );
rahul_dahiya 0:fb8047b156bb 1058 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T1, &T1, &Q->X ) ); MOD_MUL( T1 );
rahul_dahiya 0:fb8047b156bb 1059 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T2, &T2, &Q->Y ) ); MOD_MUL( T2 );
rahul_dahiya 0:fb8047b156bb 1060 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T1, &T1, &P->X ) ); MOD_SUB( T1 );
rahul_dahiya 0:fb8047b156bb 1061 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T2, &T2, &P->Y ) ); MOD_SUB( T2 );
rahul_dahiya 0:fb8047b156bb 1062
rahul_dahiya 0:fb8047b156bb 1063 /* Special cases (2) and (3) */
rahul_dahiya 0:fb8047b156bb 1064 if( mbedtls_mpi_cmp_int( &T1, 0 ) == 0 )
rahul_dahiya 0:fb8047b156bb 1065 {
rahul_dahiya 0:fb8047b156bb 1066 if( mbedtls_mpi_cmp_int( &T2, 0 ) == 0 )
rahul_dahiya 0:fb8047b156bb 1067 {
rahul_dahiya 0:fb8047b156bb 1068 ret = ecp_double_jac( grp, R, P );
rahul_dahiya 0:fb8047b156bb 1069 goto cleanup;
rahul_dahiya 0:fb8047b156bb 1070 }
rahul_dahiya 0:fb8047b156bb 1071 else
rahul_dahiya 0:fb8047b156bb 1072 {
rahul_dahiya 0:fb8047b156bb 1073 ret = mbedtls_ecp_set_zero( R );
rahul_dahiya 0:fb8047b156bb 1074 goto cleanup;
rahul_dahiya 0:fb8047b156bb 1075 }
rahul_dahiya 0:fb8047b156bb 1076 }
rahul_dahiya 0:fb8047b156bb 1077
rahul_dahiya 0:fb8047b156bb 1078 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &Z, &P->Z, &T1 ) ); MOD_MUL( Z );
rahul_dahiya 0:fb8047b156bb 1079 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T3, &T1, &T1 ) ); MOD_MUL( T3 );
rahul_dahiya 0:fb8047b156bb 1080 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T4, &T3, &T1 ) ); MOD_MUL( T4 );
rahul_dahiya 0:fb8047b156bb 1081 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T3, &T3, &P->X ) ); MOD_MUL( T3 );
rahul_dahiya 0:fb8047b156bb 1082 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_int( &T1, &T3, 2 ) ); MOD_ADD( T1 );
rahul_dahiya 0:fb8047b156bb 1083 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &X, &T2, &T2 ) ); MOD_MUL( X );
rahul_dahiya 0:fb8047b156bb 1084 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &X, &X, &T1 ) ); MOD_SUB( X );
rahul_dahiya 0:fb8047b156bb 1085 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &X, &X, &T4 ) ); MOD_SUB( X );
rahul_dahiya 0:fb8047b156bb 1086 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T3, &T3, &X ) ); MOD_SUB( T3 );
rahul_dahiya 0:fb8047b156bb 1087 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T3, &T3, &T2 ) ); MOD_MUL( T3 );
rahul_dahiya 0:fb8047b156bb 1088 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T4, &T4, &P->Y ) ); MOD_MUL( T4 );
rahul_dahiya 0:fb8047b156bb 1089 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &Y, &T3, &T4 ) ); MOD_SUB( Y );
rahul_dahiya 0:fb8047b156bb 1090
rahul_dahiya 0:fb8047b156bb 1091 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R->X, &X ) );
rahul_dahiya 0:fb8047b156bb 1092 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R->Y, &Y ) );
rahul_dahiya 0:fb8047b156bb 1093 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &R->Z, &Z ) );
rahul_dahiya 0:fb8047b156bb 1094
rahul_dahiya 0:fb8047b156bb 1095 cleanup:
rahul_dahiya 0:fb8047b156bb 1096
rahul_dahiya 0:fb8047b156bb 1097 mbedtls_mpi_free( &T1 ); mbedtls_mpi_free( &T2 ); mbedtls_mpi_free( &T3 ); mbedtls_mpi_free( &T4 );
rahul_dahiya 0:fb8047b156bb 1098 mbedtls_mpi_free( &X ); mbedtls_mpi_free( &Y ); mbedtls_mpi_free( &Z );
rahul_dahiya 0:fb8047b156bb 1099
rahul_dahiya 0:fb8047b156bb 1100 return( ret );
rahul_dahiya 0:fb8047b156bb 1101 }
rahul_dahiya 0:fb8047b156bb 1102
rahul_dahiya 0:fb8047b156bb 1103 /*
rahul_dahiya 0:fb8047b156bb 1104 * Randomize jacobian coordinates:
rahul_dahiya 0:fb8047b156bb 1105 * (X, Y, Z) -> (l^2 X, l^3 Y, l Z) for random l
rahul_dahiya 0:fb8047b156bb 1106 * This is sort of the reverse operation of ecp_normalize_jac().
rahul_dahiya 0:fb8047b156bb 1107 *
rahul_dahiya 0:fb8047b156bb 1108 * This countermeasure was first suggested in [2].
rahul_dahiya 0:fb8047b156bb 1109 */
rahul_dahiya 0:fb8047b156bb 1110 static int ecp_randomize_jac( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
rahul_dahiya 0:fb8047b156bb 1111 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
rahul_dahiya 0:fb8047b156bb 1112 {
rahul_dahiya 0:fb8047b156bb 1113 int ret;
rahul_dahiya 0:fb8047b156bb 1114 mbedtls_mpi l, ll;
rahul_dahiya 0:fb8047b156bb 1115 size_t p_size;
rahul_dahiya 0:fb8047b156bb 1116 int count = 0;
rahul_dahiya 0:fb8047b156bb 1117
rahul_dahiya 0:fb8047b156bb 1118 #if defined(MBEDTLS_ECP_RANDOMIZE_JAC_ALT)
rahul_dahiya 0:fb8047b156bb 1119 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1120 {
rahul_dahiya 0:fb8047b156bb 1121 return mbedtls_internal_ecp_randomize_jac( grp, pt, f_rng, p_rng );
rahul_dahiya 0:fb8047b156bb 1122 }
rahul_dahiya 0:fb8047b156bb 1123 #endif /* MBEDTLS_ECP_RANDOMIZE_JAC_ALT */
rahul_dahiya 0:fb8047b156bb 1124
rahul_dahiya 0:fb8047b156bb 1125 p_size = ( grp->pbits + 7 ) / 8;
rahul_dahiya 0:fb8047b156bb 1126 mbedtls_mpi_init( &l ); mbedtls_mpi_init( &ll );
rahul_dahiya 0:fb8047b156bb 1127
rahul_dahiya 0:fb8047b156bb 1128 /* Generate l such that 1 < l < p */
rahul_dahiya 0:fb8047b156bb 1129 do
rahul_dahiya 0:fb8047b156bb 1130 {
rahul_dahiya 0:fb8047b156bb 1131 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1132
rahul_dahiya 0:fb8047b156bb 1133 while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
rahul_dahiya 0:fb8047b156bb 1134 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );
rahul_dahiya 0:fb8047b156bb 1135
rahul_dahiya 0:fb8047b156bb 1136 if( count++ > 10 )
rahul_dahiya 0:fb8047b156bb 1137 return( MBEDTLS_ERR_ECP_RANDOM_FAILED );
rahul_dahiya 0:fb8047b156bb 1138 }
rahul_dahiya 0:fb8047b156bb 1139 while( mbedtls_mpi_cmp_int( &l, 1 ) <= 0 );
rahul_dahiya 0:fb8047b156bb 1140
rahul_dahiya 0:fb8047b156bb 1141 /* Z = l * Z */
rahul_dahiya 0:fb8047b156bb 1142 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &pt->Z, &pt->Z, &l ) ); MOD_MUL( pt->Z );
rahul_dahiya 0:fb8047b156bb 1143
rahul_dahiya 0:fb8047b156bb 1144 /* X = l^2 * X */
rahul_dahiya 0:fb8047b156bb 1145 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ll, &l, &l ) ); MOD_MUL( ll );
rahul_dahiya 0:fb8047b156bb 1146 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &pt->X, &pt->X, &ll ) ); MOD_MUL( pt->X );
rahul_dahiya 0:fb8047b156bb 1147
rahul_dahiya 0:fb8047b156bb 1148 /* Y = l^3 * Y */
rahul_dahiya 0:fb8047b156bb 1149 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ll, &ll, &l ) ); MOD_MUL( ll );
rahul_dahiya 0:fb8047b156bb 1150 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &pt->Y, &pt->Y, &ll ) ); MOD_MUL( pt->Y );
rahul_dahiya 0:fb8047b156bb 1151
rahul_dahiya 0:fb8047b156bb 1152 cleanup:
rahul_dahiya 0:fb8047b156bb 1153 mbedtls_mpi_free( &l ); mbedtls_mpi_free( &ll );
rahul_dahiya 0:fb8047b156bb 1154
rahul_dahiya 0:fb8047b156bb 1155 return( ret );
rahul_dahiya 0:fb8047b156bb 1156 }
rahul_dahiya 0:fb8047b156bb 1157
rahul_dahiya 0:fb8047b156bb 1158 /*
rahul_dahiya 0:fb8047b156bb 1159 * Check and define parameters used by the comb method (see below for details)
rahul_dahiya 0:fb8047b156bb 1160 */
rahul_dahiya 0:fb8047b156bb 1161 #if MBEDTLS_ECP_WINDOW_SIZE < 2 || MBEDTLS_ECP_WINDOW_SIZE > 7
rahul_dahiya 0:fb8047b156bb 1162 #error "MBEDTLS_ECP_WINDOW_SIZE out of bounds"
rahul_dahiya 0:fb8047b156bb 1163 #endif
rahul_dahiya 0:fb8047b156bb 1164
rahul_dahiya 0:fb8047b156bb 1165 /* d = ceil( n / w ) */
rahul_dahiya 0:fb8047b156bb 1166 #define COMB_MAX_D ( MBEDTLS_ECP_MAX_BITS + 1 ) / 2
rahul_dahiya 0:fb8047b156bb 1167
rahul_dahiya 0:fb8047b156bb 1168 /* number of precomputed points */
rahul_dahiya 0:fb8047b156bb 1169 #define COMB_MAX_PRE ( 1 << ( MBEDTLS_ECP_WINDOW_SIZE - 1 ) )
rahul_dahiya 0:fb8047b156bb 1170
rahul_dahiya 0:fb8047b156bb 1171 /*
rahul_dahiya 0:fb8047b156bb 1172 * Compute the representation of m that will be used with our comb method.
rahul_dahiya 0:fb8047b156bb 1173 *
rahul_dahiya 0:fb8047b156bb 1174 * The basic comb method is described in GECC 3.44 for example. We use a
rahul_dahiya 0:fb8047b156bb 1175 * modified version that provides resistance to SPA by avoiding zero
rahul_dahiya 0:fb8047b156bb 1176 * digits in the representation as in [3]. We modify the method further by
rahul_dahiya 0:fb8047b156bb 1177 * requiring that all K_i be odd, which has the small cost that our
rahul_dahiya 0:fb8047b156bb 1178 * representation uses one more K_i, due to carries.
rahul_dahiya 0:fb8047b156bb 1179 *
rahul_dahiya 0:fb8047b156bb 1180 * Also, for the sake of compactness, only the seven low-order bits of x[i]
rahul_dahiya 0:fb8047b156bb 1181 * are used to represent K_i, and the msb of x[i] encodes the the sign (s_i in
rahul_dahiya 0:fb8047b156bb 1182 * the paper): it is set if and only if if s_i == -1;
rahul_dahiya 0:fb8047b156bb 1183 *
rahul_dahiya 0:fb8047b156bb 1184 * Calling conventions:
rahul_dahiya 0:fb8047b156bb 1185 * - x is an array of size d + 1
rahul_dahiya 0:fb8047b156bb 1186 * - w is the size, ie number of teeth, of the comb, and must be between
rahul_dahiya 0:fb8047b156bb 1187 * 2 and 7 (in practice, between 2 and MBEDTLS_ECP_WINDOW_SIZE)
rahul_dahiya 0:fb8047b156bb 1188 * - m is the MPI, expected to be odd and such that bitlength(m) <= w * d
rahul_dahiya 0:fb8047b156bb 1189 * (the result will be incorrect if these assumptions are not satisfied)
rahul_dahiya 0:fb8047b156bb 1190 */
rahul_dahiya 0:fb8047b156bb 1191 static void ecp_comb_fixed( unsigned char x[], size_t d,
rahul_dahiya 0:fb8047b156bb 1192 unsigned char w, const mbedtls_mpi *m )
rahul_dahiya 0:fb8047b156bb 1193 {
rahul_dahiya 0:fb8047b156bb 1194 size_t i, j;
rahul_dahiya 0:fb8047b156bb 1195 unsigned char c, cc, adjust;
rahul_dahiya 0:fb8047b156bb 1196
rahul_dahiya 0:fb8047b156bb 1197 memset( x, 0, d+1 );
rahul_dahiya 0:fb8047b156bb 1198
rahul_dahiya 0:fb8047b156bb 1199 /* First get the classical comb values (except for x_d = 0) */
rahul_dahiya 0:fb8047b156bb 1200 for( i = 0; i < d; i++ )
rahul_dahiya 0:fb8047b156bb 1201 for( j = 0; j < w; j++ )
rahul_dahiya 0:fb8047b156bb 1202 x[i] |= mbedtls_mpi_get_bit( m, i + d * j ) << j;
rahul_dahiya 0:fb8047b156bb 1203
rahul_dahiya 0:fb8047b156bb 1204 /* Now make sure x_1 .. x_d are odd */
rahul_dahiya 0:fb8047b156bb 1205 c = 0;
rahul_dahiya 0:fb8047b156bb 1206 for( i = 1; i <= d; i++ )
rahul_dahiya 0:fb8047b156bb 1207 {
rahul_dahiya 0:fb8047b156bb 1208 /* Add carry and update it */
rahul_dahiya 0:fb8047b156bb 1209 cc = x[i] & c;
rahul_dahiya 0:fb8047b156bb 1210 x[i] = x[i] ^ c;
rahul_dahiya 0:fb8047b156bb 1211 c = cc;
rahul_dahiya 0:fb8047b156bb 1212
rahul_dahiya 0:fb8047b156bb 1213 /* Adjust if needed, avoiding branches */
rahul_dahiya 0:fb8047b156bb 1214 adjust = 1 - ( x[i] & 0x01 );
rahul_dahiya 0:fb8047b156bb 1215 c |= x[i] & ( x[i-1] * adjust );
rahul_dahiya 0:fb8047b156bb 1216 x[i] = x[i] ^ ( x[i-1] * adjust );
rahul_dahiya 0:fb8047b156bb 1217 x[i-1] |= adjust << 7;
rahul_dahiya 0:fb8047b156bb 1218 }
rahul_dahiya 0:fb8047b156bb 1219 }
rahul_dahiya 0:fb8047b156bb 1220
rahul_dahiya 0:fb8047b156bb 1221 /*
rahul_dahiya 0:fb8047b156bb 1222 * Precompute points for the comb method
rahul_dahiya 0:fb8047b156bb 1223 *
rahul_dahiya 0:fb8047b156bb 1224 * If i = i_{w-1} ... i_1 is the binary representation of i, then
rahul_dahiya 0:fb8047b156bb 1225 * T[i] = i_{w-1} 2^{(w-1)d} P + ... + i_1 2^d P + P
rahul_dahiya 0:fb8047b156bb 1226 *
rahul_dahiya 0:fb8047b156bb 1227 * T must be able to hold 2^{w - 1} elements
rahul_dahiya 0:fb8047b156bb 1228 *
rahul_dahiya 0:fb8047b156bb 1229 * Cost: d(w-1) D + (2^{w-1} - 1) A + 1 N(w-1) + 1 N(2^{w-1} - 1)
rahul_dahiya 0:fb8047b156bb 1230 */
rahul_dahiya 0:fb8047b156bb 1231 static int ecp_precompute_comb( const mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 1232 mbedtls_ecp_point T[], const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 1233 unsigned char w, size_t d )
rahul_dahiya 0:fb8047b156bb 1234 {
rahul_dahiya 0:fb8047b156bb 1235 int ret;
rahul_dahiya 0:fb8047b156bb 1236 unsigned char i, k;
rahul_dahiya 0:fb8047b156bb 1237 size_t j;
rahul_dahiya 0:fb8047b156bb 1238 mbedtls_ecp_point *cur, *TT[COMB_MAX_PRE - 1];
rahul_dahiya 0:fb8047b156bb 1239
rahul_dahiya 0:fb8047b156bb 1240 /*
rahul_dahiya 0:fb8047b156bb 1241 * Set T[0] = P and
rahul_dahiya 0:fb8047b156bb 1242 * T[2^{l-1}] = 2^{dl} P for l = 1 .. w-1 (this is not the final value)
rahul_dahiya 0:fb8047b156bb 1243 */
rahul_dahiya 0:fb8047b156bb 1244 MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &T[0], P ) );
rahul_dahiya 0:fb8047b156bb 1245
rahul_dahiya 0:fb8047b156bb 1246 k = 0;
rahul_dahiya 0:fb8047b156bb 1247 for( i = 1; i < ( 1U << ( w - 1 ) ); i <<= 1 )
rahul_dahiya 0:fb8047b156bb 1248 {
rahul_dahiya 0:fb8047b156bb 1249 cur = T + i;
rahul_dahiya 0:fb8047b156bb 1250 MBEDTLS_MPI_CHK( mbedtls_ecp_copy( cur, T + ( i >> 1 ) ) );
rahul_dahiya 0:fb8047b156bb 1251 for( j = 0; j < d; j++ )
rahul_dahiya 0:fb8047b156bb 1252 MBEDTLS_MPI_CHK( ecp_double_jac( grp, cur, cur ) );
rahul_dahiya 0:fb8047b156bb 1253
rahul_dahiya 0:fb8047b156bb 1254 TT[k++] = cur;
rahul_dahiya 0:fb8047b156bb 1255 }
rahul_dahiya 0:fb8047b156bb 1256
rahul_dahiya 0:fb8047b156bb 1257 MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, k ) );
rahul_dahiya 0:fb8047b156bb 1258
rahul_dahiya 0:fb8047b156bb 1259 /*
rahul_dahiya 0:fb8047b156bb 1260 * Compute the remaining ones using the minimal number of additions
rahul_dahiya 0:fb8047b156bb 1261 * Be careful to update T[2^l] only after using it!
rahul_dahiya 0:fb8047b156bb 1262 */
rahul_dahiya 0:fb8047b156bb 1263 k = 0;
rahul_dahiya 0:fb8047b156bb 1264 for( i = 1; i < ( 1U << ( w - 1 ) ); i <<= 1 )
rahul_dahiya 0:fb8047b156bb 1265 {
rahul_dahiya 0:fb8047b156bb 1266 j = i;
rahul_dahiya 0:fb8047b156bb 1267 while( j-- )
rahul_dahiya 0:fb8047b156bb 1268 {
rahul_dahiya 0:fb8047b156bb 1269 MBEDTLS_MPI_CHK( ecp_add_mixed( grp, &T[i + j], &T[j], &T[i] ) );
rahul_dahiya 0:fb8047b156bb 1270 TT[k++] = &T[i + j];
rahul_dahiya 0:fb8047b156bb 1271 }
rahul_dahiya 0:fb8047b156bb 1272 }
rahul_dahiya 0:fb8047b156bb 1273
rahul_dahiya 0:fb8047b156bb 1274 MBEDTLS_MPI_CHK( ecp_normalize_jac_many( grp, TT, k ) );
rahul_dahiya 0:fb8047b156bb 1275
rahul_dahiya 0:fb8047b156bb 1276 cleanup:
rahul_dahiya 0:fb8047b156bb 1277
rahul_dahiya 0:fb8047b156bb 1278 return( ret );
rahul_dahiya 0:fb8047b156bb 1279 }
rahul_dahiya 0:fb8047b156bb 1280
rahul_dahiya 0:fb8047b156bb 1281 /*
rahul_dahiya 0:fb8047b156bb 1282 * Select precomputed point: R = sign(i) * T[ abs(i) / 2 ]
rahul_dahiya 0:fb8047b156bb 1283 */
rahul_dahiya 0:fb8047b156bb 1284 static int ecp_select_comb( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1285 const mbedtls_ecp_point T[], unsigned char t_len,
rahul_dahiya 0:fb8047b156bb 1286 unsigned char i )
rahul_dahiya 0:fb8047b156bb 1287 {
rahul_dahiya 0:fb8047b156bb 1288 int ret;
rahul_dahiya 0:fb8047b156bb 1289 unsigned char ii, j;
rahul_dahiya 0:fb8047b156bb 1290
rahul_dahiya 0:fb8047b156bb 1291 /* Ignore the "sign" bit and scale down */
rahul_dahiya 0:fb8047b156bb 1292 ii = ( i & 0x7Fu ) >> 1;
rahul_dahiya 0:fb8047b156bb 1293
rahul_dahiya 0:fb8047b156bb 1294 /* Read the whole table to thwart cache-based timing attacks */
rahul_dahiya 0:fb8047b156bb 1295 for( j = 0; j < t_len; j++ )
rahul_dahiya 0:fb8047b156bb 1296 {
rahul_dahiya 0:fb8047b156bb 1297 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &R->X, &T[j].X, j == ii ) );
rahul_dahiya 0:fb8047b156bb 1298 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &R->Y, &T[j].Y, j == ii ) );
rahul_dahiya 0:fb8047b156bb 1299 }
rahul_dahiya 0:fb8047b156bb 1300
rahul_dahiya 0:fb8047b156bb 1301 /* Safely invert result if i is "negative" */
rahul_dahiya 0:fb8047b156bb 1302 MBEDTLS_MPI_CHK( ecp_safe_invert_jac( grp, R, i >> 7 ) );
rahul_dahiya 0:fb8047b156bb 1303
rahul_dahiya 0:fb8047b156bb 1304 cleanup:
rahul_dahiya 0:fb8047b156bb 1305 return( ret );
rahul_dahiya 0:fb8047b156bb 1306 }
rahul_dahiya 0:fb8047b156bb 1307
rahul_dahiya 0:fb8047b156bb 1308 /*
rahul_dahiya 0:fb8047b156bb 1309 * Core multiplication algorithm for the (modified) comb method.
rahul_dahiya 0:fb8047b156bb 1310 * This part is actually common with the basic comb method (GECC 3.44)
rahul_dahiya 0:fb8047b156bb 1311 *
rahul_dahiya 0:fb8047b156bb 1312 * Cost: d A + d D + 1 R
rahul_dahiya 0:fb8047b156bb 1313 */
rahul_dahiya 0:fb8047b156bb 1314 static int ecp_mul_comb_core( const mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1315 const mbedtls_ecp_point T[], unsigned char t_len,
rahul_dahiya 0:fb8047b156bb 1316 const unsigned char x[], size_t d,
rahul_dahiya 0:fb8047b156bb 1317 int (*f_rng)(void *, unsigned char *, size_t),
rahul_dahiya 0:fb8047b156bb 1318 void *p_rng )
rahul_dahiya 0:fb8047b156bb 1319 {
rahul_dahiya 0:fb8047b156bb 1320 int ret;
rahul_dahiya 0:fb8047b156bb 1321 mbedtls_ecp_point Txi;
rahul_dahiya 0:fb8047b156bb 1322 size_t i;
rahul_dahiya 0:fb8047b156bb 1323
rahul_dahiya 0:fb8047b156bb 1324 mbedtls_ecp_point_init( &Txi );
rahul_dahiya 0:fb8047b156bb 1325
rahul_dahiya 0:fb8047b156bb 1326 /* Start with a non-zero point and randomize its coordinates */
rahul_dahiya 0:fb8047b156bb 1327 i = d;
rahul_dahiya 0:fb8047b156bb 1328 MBEDTLS_MPI_CHK( ecp_select_comb( grp, R, T, t_len, x[i] ) );
rahul_dahiya 0:fb8047b156bb 1329 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 1 ) );
rahul_dahiya 0:fb8047b156bb 1330 if( f_rng != 0 )
rahul_dahiya 0:fb8047b156bb 1331 MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, R, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1332
rahul_dahiya 0:fb8047b156bb 1333 while( i-- != 0 )
rahul_dahiya 0:fb8047b156bb 1334 {
rahul_dahiya 0:fb8047b156bb 1335 MBEDTLS_MPI_CHK( ecp_double_jac( grp, R, R ) );
rahul_dahiya 0:fb8047b156bb 1336 MBEDTLS_MPI_CHK( ecp_select_comb( grp, &Txi, T, t_len, x[i] ) );
rahul_dahiya 0:fb8047b156bb 1337 MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, R, &Txi ) );
rahul_dahiya 0:fb8047b156bb 1338 }
rahul_dahiya 0:fb8047b156bb 1339
rahul_dahiya 0:fb8047b156bb 1340 cleanup:
rahul_dahiya 0:fb8047b156bb 1341
rahul_dahiya 0:fb8047b156bb 1342 mbedtls_ecp_point_free( &Txi );
rahul_dahiya 0:fb8047b156bb 1343
rahul_dahiya 0:fb8047b156bb 1344 return( ret );
rahul_dahiya 0:fb8047b156bb 1345 }
rahul_dahiya 0:fb8047b156bb 1346
rahul_dahiya 0:fb8047b156bb 1347 /*
rahul_dahiya 0:fb8047b156bb 1348 * Multiplication using the comb method,
rahul_dahiya 0:fb8047b156bb 1349 * for curves in short Weierstrass form
rahul_dahiya 0:fb8047b156bb 1350 */
rahul_dahiya 0:fb8047b156bb 1351 static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1352 const mbedtls_mpi *m, const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 1353 int (*f_rng)(void *, unsigned char *, size_t),
rahul_dahiya 0:fb8047b156bb 1354 void *p_rng )
rahul_dahiya 0:fb8047b156bb 1355 {
rahul_dahiya 0:fb8047b156bb 1356 int ret;
rahul_dahiya 0:fb8047b156bb 1357 unsigned char w, m_is_odd, p_eq_g, pre_len, i;
rahul_dahiya 0:fb8047b156bb 1358 size_t d;
rahul_dahiya 0:fb8047b156bb 1359 unsigned char k[COMB_MAX_D + 1];
rahul_dahiya 0:fb8047b156bb 1360 mbedtls_ecp_point *T;
rahul_dahiya 0:fb8047b156bb 1361 mbedtls_mpi M, mm;
rahul_dahiya 0:fb8047b156bb 1362
rahul_dahiya 0:fb8047b156bb 1363 mbedtls_mpi_init( &M );
rahul_dahiya 0:fb8047b156bb 1364 mbedtls_mpi_init( &mm );
rahul_dahiya 0:fb8047b156bb 1365
rahul_dahiya 0:fb8047b156bb 1366 /* we need N to be odd to trnaform m in an odd number, check now */
rahul_dahiya 0:fb8047b156bb 1367 if( mbedtls_mpi_get_bit( &grp->N, 0 ) != 1 )
rahul_dahiya 0:fb8047b156bb 1368 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 1369
rahul_dahiya 0:fb8047b156bb 1370 /*
rahul_dahiya 0:fb8047b156bb 1371 * Minimize the number of multiplications, that is minimize
rahul_dahiya 0:fb8047b156bb 1372 * 10 * d * w + 18 * 2^(w-1) + 11 * d + 7 * w, with d = ceil( nbits / w )
rahul_dahiya 0:fb8047b156bb 1373 * (see costs of the various parts, with 1S = 1M)
rahul_dahiya 0:fb8047b156bb 1374 */
rahul_dahiya 0:fb8047b156bb 1375 w = grp->nbits >= 384 ? 5 : 4;
rahul_dahiya 0:fb8047b156bb 1376
rahul_dahiya 0:fb8047b156bb 1377 /*
rahul_dahiya 0:fb8047b156bb 1378 * If P == G, pre-compute a bit more, since this may be re-used later.
rahul_dahiya 0:fb8047b156bb 1379 * Just adding one avoids upping the cost of the first mul too much,
rahul_dahiya 0:fb8047b156bb 1380 * and the memory cost too.
rahul_dahiya 0:fb8047b156bb 1381 */
rahul_dahiya 0:fb8047b156bb 1382 #if MBEDTLS_ECP_FIXED_POINT_OPTIM == 1
rahul_dahiya 0:fb8047b156bb 1383 p_eq_g = ( mbedtls_mpi_cmp_mpi( &P->Y, &grp->G.Y ) == 0 &&
rahul_dahiya 0:fb8047b156bb 1384 mbedtls_mpi_cmp_mpi( &P->X, &grp->G.X ) == 0 );
rahul_dahiya 0:fb8047b156bb 1385 if( p_eq_g )
rahul_dahiya 0:fb8047b156bb 1386 w++;
rahul_dahiya 0:fb8047b156bb 1387 #else
rahul_dahiya 0:fb8047b156bb 1388 p_eq_g = 0;
rahul_dahiya 0:fb8047b156bb 1389 #endif
rahul_dahiya 0:fb8047b156bb 1390
rahul_dahiya 0:fb8047b156bb 1391 /*
rahul_dahiya 0:fb8047b156bb 1392 * Make sure w is within bounds.
rahul_dahiya 0:fb8047b156bb 1393 * (The last test is useful only for very small curves in the test suite.)
rahul_dahiya 0:fb8047b156bb 1394 */
rahul_dahiya 0:fb8047b156bb 1395 if( w > MBEDTLS_ECP_WINDOW_SIZE )
rahul_dahiya 0:fb8047b156bb 1396 w = MBEDTLS_ECP_WINDOW_SIZE;
rahul_dahiya 0:fb8047b156bb 1397 if( w >= grp->nbits )
rahul_dahiya 0:fb8047b156bb 1398 w = 2;
rahul_dahiya 0:fb8047b156bb 1399
rahul_dahiya 0:fb8047b156bb 1400 /* Other sizes that depend on w */
rahul_dahiya 0:fb8047b156bb 1401 pre_len = 1U << ( w - 1 );
rahul_dahiya 0:fb8047b156bb 1402 d = ( grp->nbits + w - 1 ) / w;
rahul_dahiya 0:fb8047b156bb 1403
rahul_dahiya 0:fb8047b156bb 1404 /*
rahul_dahiya 0:fb8047b156bb 1405 * Prepare precomputed points: if P == G we want to
rahul_dahiya 0:fb8047b156bb 1406 * use grp->T if already initialized, or initialize it.
rahul_dahiya 0:fb8047b156bb 1407 */
rahul_dahiya 0:fb8047b156bb 1408 T = p_eq_g ? grp->T : NULL;
rahul_dahiya 0:fb8047b156bb 1409
rahul_dahiya 0:fb8047b156bb 1410 if( T == NULL )
rahul_dahiya 0:fb8047b156bb 1411 {
rahul_dahiya 0:fb8047b156bb 1412 T = mbedtls_calloc( pre_len, sizeof( mbedtls_ecp_point ) );
rahul_dahiya 0:fb8047b156bb 1413 if( T == NULL )
rahul_dahiya 0:fb8047b156bb 1414 {
rahul_dahiya 0:fb8047b156bb 1415 ret = MBEDTLS_ERR_ECP_ALLOC_FAILED;
rahul_dahiya 0:fb8047b156bb 1416 goto cleanup;
rahul_dahiya 0:fb8047b156bb 1417 }
rahul_dahiya 0:fb8047b156bb 1418
rahul_dahiya 0:fb8047b156bb 1419 MBEDTLS_MPI_CHK( ecp_precompute_comb( grp, T, P, w, d ) );
rahul_dahiya 0:fb8047b156bb 1420
rahul_dahiya 0:fb8047b156bb 1421 if( p_eq_g )
rahul_dahiya 0:fb8047b156bb 1422 {
rahul_dahiya 0:fb8047b156bb 1423 grp->T = T;
rahul_dahiya 0:fb8047b156bb 1424 grp->T_size = pre_len;
rahul_dahiya 0:fb8047b156bb 1425 }
rahul_dahiya 0:fb8047b156bb 1426 }
rahul_dahiya 0:fb8047b156bb 1427
rahul_dahiya 0:fb8047b156bb 1428 /*
rahul_dahiya 0:fb8047b156bb 1429 * Make sure M is odd (M = m or M = N - m, since N is odd)
rahul_dahiya 0:fb8047b156bb 1430 * using the fact that m * P = - (N - m) * P
rahul_dahiya 0:fb8047b156bb 1431 */
rahul_dahiya 0:fb8047b156bb 1432 m_is_odd = ( mbedtls_mpi_get_bit( m, 0 ) == 1 );
rahul_dahiya 0:fb8047b156bb 1433 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &M, m ) );
rahul_dahiya 0:fb8047b156bb 1434 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &mm, &grp->N, m ) );
rahul_dahiya 0:fb8047b156bb 1435 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( &M, &mm, ! m_is_odd ) );
rahul_dahiya 0:fb8047b156bb 1436
rahul_dahiya 0:fb8047b156bb 1437 /*
rahul_dahiya 0:fb8047b156bb 1438 * Go for comb multiplication, R = M * P
rahul_dahiya 0:fb8047b156bb 1439 */
rahul_dahiya 0:fb8047b156bb 1440 ecp_comb_fixed( k, d, w, &M );
rahul_dahiya 0:fb8047b156bb 1441 MBEDTLS_MPI_CHK( ecp_mul_comb_core( grp, R, T, pre_len, k, d, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1442
rahul_dahiya 0:fb8047b156bb 1443 /*
rahul_dahiya 0:fb8047b156bb 1444 * Now get m * P from M * P and normalize it
rahul_dahiya 0:fb8047b156bb 1445 */
rahul_dahiya 0:fb8047b156bb 1446 MBEDTLS_MPI_CHK( ecp_safe_invert_jac( grp, R, ! m_is_odd ) );
rahul_dahiya 0:fb8047b156bb 1447 MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) );
rahul_dahiya 0:fb8047b156bb 1448
rahul_dahiya 0:fb8047b156bb 1449 cleanup:
rahul_dahiya 0:fb8047b156bb 1450
rahul_dahiya 0:fb8047b156bb 1451 if( T != NULL && ! p_eq_g )
rahul_dahiya 0:fb8047b156bb 1452 {
rahul_dahiya 0:fb8047b156bb 1453 for( i = 0; i < pre_len; i++ )
rahul_dahiya 0:fb8047b156bb 1454 mbedtls_ecp_point_free( &T[i] );
rahul_dahiya 0:fb8047b156bb 1455 mbedtls_free( T );
rahul_dahiya 0:fb8047b156bb 1456 }
rahul_dahiya 0:fb8047b156bb 1457
rahul_dahiya 0:fb8047b156bb 1458 mbedtls_mpi_free( &M );
rahul_dahiya 0:fb8047b156bb 1459 mbedtls_mpi_free( &mm );
rahul_dahiya 0:fb8047b156bb 1460
rahul_dahiya 0:fb8047b156bb 1461 if( ret != 0 )
rahul_dahiya 0:fb8047b156bb 1462 mbedtls_ecp_point_free( R );
rahul_dahiya 0:fb8047b156bb 1463
rahul_dahiya 0:fb8047b156bb 1464 return( ret );
rahul_dahiya 0:fb8047b156bb 1465 }
rahul_dahiya 0:fb8047b156bb 1466
rahul_dahiya 0:fb8047b156bb 1467 #endif /* ECP_SHORTWEIERSTRASS */
rahul_dahiya 0:fb8047b156bb 1468
rahul_dahiya 0:fb8047b156bb 1469 #if defined(ECP_MONTGOMERY)
rahul_dahiya 0:fb8047b156bb 1470 /*
rahul_dahiya 0:fb8047b156bb 1471 * For Montgomery curves, we do all the internal arithmetic in projective
rahul_dahiya 0:fb8047b156bb 1472 * coordinates. Import/export of points uses only the x coordinates, which is
rahul_dahiya 0:fb8047b156bb 1473 * internaly represented as X / Z.
rahul_dahiya 0:fb8047b156bb 1474 *
rahul_dahiya 0:fb8047b156bb 1475 * For scalar multiplication, we'll use a Montgomery ladder.
rahul_dahiya 0:fb8047b156bb 1476 */
rahul_dahiya 0:fb8047b156bb 1477
rahul_dahiya 0:fb8047b156bb 1478 /*
rahul_dahiya 0:fb8047b156bb 1479 * Normalize Montgomery x/z coordinates: X = X/Z, Z = 1
rahul_dahiya 0:fb8047b156bb 1480 * Cost: 1M + 1I
rahul_dahiya 0:fb8047b156bb 1481 */
rahul_dahiya 0:fb8047b156bb 1482 static int ecp_normalize_mxz( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P )
rahul_dahiya 0:fb8047b156bb 1483 {
rahul_dahiya 0:fb8047b156bb 1484 int ret;
rahul_dahiya 0:fb8047b156bb 1485
rahul_dahiya 0:fb8047b156bb 1486 #if defined(MBEDTLS_ECP_NORMALIZE_MXZ_ALT)
rahul_dahiya 0:fb8047b156bb 1487 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1488 {
rahul_dahiya 0:fb8047b156bb 1489 return mbedtls_internal_ecp_normalize_mxz( grp, P );
rahul_dahiya 0:fb8047b156bb 1490 }
rahul_dahiya 0:fb8047b156bb 1491 #endif /* MBEDTLS_ECP_NORMALIZE_MXZ_ALT */
rahul_dahiya 0:fb8047b156bb 1492
rahul_dahiya 0:fb8047b156bb 1493 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &P->Z, &P->Z, &grp->P ) );
rahul_dahiya 0:fb8047b156bb 1494 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &P->X, &P->X, &P->Z ) ); MOD_MUL( P->X );
rahul_dahiya 0:fb8047b156bb 1495 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &P->Z, 1 ) );
rahul_dahiya 0:fb8047b156bb 1496
rahul_dahiya 0:fb8047b156bb 1497 cleanup:
rahul_dahiya 0:fb8047b156bb 1498 return( ret );
rahul_dahiya 0:fb8047b156bb 1499 }
rahul_dahiya 0:fb8047b156bb 1500
rahul_dahiya 0:fb8047b156bb 1501 /*
rahul_dahiya 0:fb8047b156bb 1502 * Randomize projective x/z coordinates:
rahul_dahiya 0:fb8047b156bb 1503 * (X, Z) -> (l X, l Z) for random l
rahul_dahiya 0:fb8047b156bb 1504 * This is sort of the reverse operation of ecp_normalize_mxz().
rahul_dahiya 0:fb8047b156bb 1505 *
rahul_dahiya 0:fb8047b156bb 1506 * This countermeasure was first suggested in [2].
rahul_dahiya 0:fb8047b156bb 1507 * Cost: 2M
rahul_dahiya 0:fb8047b156bb 1508 */
rahul_dahiya 0:fb8047b156bb 1509 static int ecp_randomize_mxz( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 1510 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
rahul_dahiya 0:fb8047b156bb 1511 {
rahul_dahiya 0:fb8047b156bb 1512 int ret;
rahul_dahiya 0:fb8047b156bb 1513 mbedtls_mpi l;
rahul_dahiya 0:fb8047b156bb 1514 size_t p_size;
rahul_dahiya 0:fb8047b156bb 1515 int count = 0;
rahul_dahiya 0:fb8047b156bb 1516
rahul_dahiya 0:fb8047b156bb 1517 #if defined(MBEDTLS_ECP_RANDOMIZE_MXZ_ALT)
rahul_dahiya 0:fb8047b156bb 1518 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1519 {
rahul_dahiya 0:fb8047b156bb 1520 return mbedtls_internal_ecp_randomize_mxz( grp, P, f_rng, p_rng );
rahul_dahiya 0:fb8047b156bb 1521 }
rahul_dahiya 0:fb8047b156bb 1522 #endif /* MBEDTLS_ECP_RANDOMIZE_MXZ_ALT */
rahul_dahiya 0:fb8047b156bb 1523
rahul_dahiya 0:fb8047b156bb 1524 p_size = ( grp->pbits + 7 ) / 8;
rahul_dahiya 0:fb8047b156bb 1525 mbedtls_mpi_init( &l );
rahul_dahiya 0:fb8047b156bb 1526
rahul_dahiya 0:fb8047b156bb 1527 /* Generate l such that 1 < l < p */
rahul_dahiya 0:fb8047b156bb 1528 do
rahul_dahiya 0:fb8047b156bb 1529 {
rahul_dahiya 0:fb8047b156bb 1530 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1531
rahul_dahiya 0:fb8047b156bb 1532 while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
rahul_dahiya 0:fb8047b156bb 1533 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );
rahul_dahiya 0:fb8047b156bb 1534
rahul_dahiya 0:fb8047b156bb 1535 if( count++ > 10 )
rahul_dahiya 0:fb8047b156bb 1536 return( MBEDTLS_ERR_ECP_RANDOM_FAILED );
rahul_dahiya 0:fb8047b156bb 1537 }
rahul_dahiya 0:fb8047b156bb 1538 while( mbedtls_mpi_cmp_int( &l, 1 ) <= 0 );
rahul_dahiya 0:fb8047b156bb 1539
rahul_dahiya 0:fb8047b156bb 1540 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &P->X, &P->X, &l ) ); MOD_MUL( P->X );
rahul_dahiya 0:fb8047b156bb 1541 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &P->Z, &P->Z, &l ) ); MOD_MUL( P->Z );
rahul_dahiya 0:fb8047b156bb 1542
rahul_dahiya 0:fb8047b156bb 1543 cleanup:
rahul_dahiya 0:fb8047b156bb 1544 mbedtls_mpi_free( &l );
rahul_dahiya 0:fb8047b156bb 1545
rahul_dahiya 0:fb8047b156bb 1546 return( ret );
rahul_dahiya 0:fb8047b156bb 1547 }
rahul_dahiya 0:fb8047b156bb 1548
rahul_dahiya 0:fb8047b156bb 1549 /*
rahul_dahiya 0:fb8047b156bb 1550 * Double-and-add: R = 2P, S = P + Q, with d = X(P - Q),
rahul_dahiya 0:fb8047b156bb 1551 * for Montgomery curves in x/z coordinates.
rahul_dahiya 0:fb8047b156bb 1552 *
rahul_dahiya 0:fb8047b156bb 1553 * http://www.hyperelliptic.org/EFD/g1p/auto-code/montgom/xz/ladder/mladd-1987-m.op3
rahul_dahiya 0:fb8047b156bb 1554 * with
rahul_dahiya 0:fb8047b156bb 1555 * d = X1
rahul_dahiya 0:fb8047b156bb 1556 * P = (X2, Z2)
rahul_dahiya 0:fb8047b156bb 1557 * Q = (X3, Z3)
rahul_dahiya 0:fb8047b156bb 1558 * R = (X4, Z4)
rahul_dahiya 0:fb8047b156bb 1559 * S = (X5, Z5)
rahul_dahiya 0:fb8047b156bb 1560 * and eliminating temporary variables tO, ..., t4.
rahul_dahiya 0:fb8047b156bb 1561 *
rahul_dahiya 0:fb8047b156bb 1562 * Cost: 5M + 4S
rahul_dahiya 0:fb8047b156bb 1563 */
rahul_dahiya 0:fb8047b156bb 1564 static int ecp_double_add_mxz( const mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 1565 mbedtls_ecp_point *R, mbedtls_ecp_point *S,
rahul_dahiya 0:fb8047b156bb 1566 const mbedtls_ecp_point *P, const mbedtls_ecp_point *Q,
rahul_dahiya 0:fb8047b156bb 1567 const mbedtls_mpi *d )
rahul_dahiya 0:fb8047b156bb 1568 {
rahul_dahiya 0:fb8047b156bb 1569 int ret;
rahul_dahiya 0:fb8047b156bb 1570 mbedtls_mpi A, AA, B, BB, E, C, D, DA, CB;
rahul_dahiya 0:fb8047b156bb 1571
rahul_dahiya 0:fb8047b156bb 1572 #if defined(MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT)
rahul_dahiya 0:fb8047b156bb 1573 if ( mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1574 {
rahul_dahiya 0:fb8047b156bb 1575 return mbedtls_internal_ecp_double_add_mxz( grp, R, S, P, Q, d );
rahul_dahiya 0:fb8047b156bb 1576 }
rahul_dahiya 0:fb8047b156bb 1577 #endif /* MBEDTLS_ECP_DOUBLE_ADD_MXZ_ALT */
rahul_dahiya 0:fb8047b156bb 1578
rahul_dahiya 0:fb8047b156bb 1579 mbedtls_mpi_init( &A ); mbedtls_mpi_init( &AA ); mbedtls_mpi_init( &B );
rahul_dahiya 0:fb8047b156bb 1580 mbedtls_mpi_init( &BB ); mbedtls_mpi_init( &E ); mbedtls_mpi_init( &C );
rahul_dahiya 0:fb8047b156bb 1581 mbedtls_mpi_init( &D ); mbedtls_mpi_init( &DA ); mbedtls_mpi_init( &CB );
rahul_dahiya 0:fb8047b156bb 1582
rahul_dahiya 0:fb8047b156bb 1583 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &A, &P->X, &P->Z ) ); MOD_ADD( A );
rahul_dahiya 0:fb8047b156bb 1584 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &AA, &A, &A ) ); MOD_MUL( AA );
rahul_dahiya 0:fb8047b156bb 1585 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &B, &P->X, &P->Z ) ); MOD_SUB( B );
rahul_dahiya 0:fb8047b156bb 1586 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &BB, &B, &B ) ); MOD_MUL( BB );
rahul_dahiya 0:fb8047b156bb 1587 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &E, &AA, &BB ) ); MOD_SUB( E );
rahul_dahiya 0:fb8047b156bb 1588 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &C, &Q->X, &Q->Z ) ); MOD_ADD( C );
rahul_dahiya 0:fb8047b156bb 1589 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &D, &Q->X, &Q->Z ) ); MOD_SUB( D );
rahul_dahiya 0:fb8047b156bb 1590 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DA, &D, &A ) ); MOD_MUL( DA );
rahul_dahiya 0:fb8047b156bb 1591 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &CB, &C, &B ) ); MOD_MUL( CB );
rahul_dahiya 0:fb8047b156bb 1592 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &S->X, &DA, &CB ) ); MOD_MUL( S->X );
rahul_dahiya 0:fb8047b156bb 1593 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S->X, &S->X, &S->X ) ); MOD_MUL( S->X );
rahul_dahiya 0:fb8047b156bb 1594 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &S->Z, &DA, &CB ) ); MOD_SUB( S->Z );
rahul_dahiya 0:fb8047b156bb 1595 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S->Z, &S->Z, &S->Z ) ); MOD_MUL( S->Z );
rahul_dahiya 0:fb8047b156bb 1596 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &S->Z, d, &S->Z ) ); MOD_MUL( S->Z );
rahul_dahiya 0:fb8047b156bb 1597 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &R->X, &AA, &BB ) ); MOD_MUL( R->X );
rahul_dahiya 0:fb8047b156bb 1598 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &R->Z, &grp->A, &E ) ); MOD_MUL( R->Z );
rahul_dahiya 0:fb8047b156bb 1599 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &R->Z, &BB, &R->Z ) ); MOD_ADD( R->Z );
rahul_dahiya 0:fb8047b156bb 1600 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &R->Z, &E, &R->Z ) ); MOD_MUL( R->Z );
rahul_dahiya 0:fb8047b156bb 1601
rahul_dahiya 0:fb8047b156bb 1602 cleanup:
rahul_dahiya 0:fb8047b156bb 1603 mbedtls_mpi_free( &A ); mbedtls_mpi_free( &AA ); mbedtls_mpi_free( &B );
rahul_dahiya 0:fb8047b156bb 1604 mbedtls_mpi_free( &BB ); mbedtls_mpi_free( &E ); mbedtls_mpi_free( &C );
rahul_dahiya 0:fb8047b156bb 1605 mbedtls_mpi_free( &D ); mbedtls_mpi_free( &DA ); mbedtls_mpi_free( &CB );
rahul_dahiya 0:fb8047b156bb 1606
rahul_dahiya 0:fb8047b156bb 1607 return( ret );
rahul_dahiya 0:fb8047b156bb 1608 }
rahul_dahiya 0:fb8047b156bb 1609
rahul_dahiya 0:fb8047b156bb 1610 /*
rahul_dahiya 0:fb8047b156bb 1611 * Multiplication with Montgomery ladder in x/z coordinates,
rahul_dahiya 0:fb8047b156bb 1612 * for curves in Montgomery form
rahul_dahiya 0:fb8047b156bb 1613 */
rahul_dahiya 0:fb8047b156bb 1614 static int ecp_mul_mxz( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1615 const mbedtls_mpi *m, const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 1616 int (*f_rng)(void *, unsigned char *, size_t),
rahul_dahiya 0:fb8047b156bb 1617 void *p_rng )
rahul_dahiya 0:fb8047b156bb 1618 {
rahul_dahiya 0:fb8047b156bb 1619 int ret;
rahul_dahiya 0:fb8047b156bb 1620 size_t i;
rahul_dahiya 0:fb8047b156bb 1621 unsigned char b;
rahul_dahiya 0:fb8047b156bb 1622 mbedtls_ecp_point RP;
rahul_dahiya 0:fb8047b156bb 1623 mbedtls_mpi PX;
rahul_dahiya 0:fb8047b156bb 1624
rahul_dahiya 0:fb8047b156bb 1625 mbedtls_ecp_point_init( &RP ); mbedtls_mpi_init( &PX );
rahul_dahiya 0:fb8047b156bb 1626
rahul_dahiya 0:fb8047b156bb 1627 /* Save PX and read from P before writing to R, in case P == R */
rahul_dahiya 0:fb8047b156bb 1628 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &PX, &P->X ) );
rahul_dahiya 0:fb8047b156bb 1629 MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &RP, P ) );
rahul_dahiya 0:fb8047b156bb 1630
rahul_dahiya 0:fb8047b156bb 1631 /* Set R to zero in modified x/z coordinates */
rahul_dahiya 0:fb8047b156bb 1632 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->X, 1 ) );
rahul_dahiya 0:fb8047b156bb 1633 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &R->Z, 0 ) );
rahul_dahiya 0:fb8047b156bb 1634 mbedtls_mpi_free( &R->Y );
rahul_dahiya 0:fb8047b156bb 1635
rahul_dahiya 0:fb8047b156bb 1636 /* RP.X might be sligtly larger than P, so reduce it */
rahul_dahiya 0:fb8047b156bb 1637 MOD_ADD( RP.X );
rahul_dahiya 0:fb8047b156bb 1638
rahul_dahiya 0:fb8047b156bb 1639 /* Randomize coordinates of the starting point */
rahul_dahiya 0:fb8047b156bb 1640 if( f_rng != NULL )
rahul_dahiya 0:fb8047b156bb 1641 MBEDTLS_MPI_CHK( ecp_randomize_mxz( grp, &RP, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1642
rahul_dahiya 0:fb8047b156bb 1643 /* Loop invariant: R = result so far, RP = R + P */
rahul_dahiya 0:fb8047b156bb 1644 i = mbedtls_mpi_bitlen( m ); /* one past the (zero-based) most significant bit */
rahul_dahiya 0:fb8047b156bb 1645 while( i-- > 0 )
rahul_dahiya 0:fb8047b156bb 1646 {
rahul_dahiya 0:fb8047b156bb 1647 b = mbedtls_mpi_get_bit( m, i );
rahul_dahiya 0:fb8047b156bb 1648 /*
rahul_dahiya 0:fb8047b156bb 1649 * if (b) R = 2R + P else R = 2R,
rahul_dahiya 0:fb8047b156bb 1650 * which is:
rahul_dahiya 0:fb8047b156bb 1651 * if (b) double_add( RP, R, RP, R )
rahul_dahiya 0:fb8047b156bb 1652 * else double_add( R, RP, R, RP )
rahul_dahiya 0:fb8047b156bb 1653 * but using safe conditional swaps to avoid leaks
rahul_dahiya 0:fb8047b156bb 1654 */
rahul_dahiya 0:fb8047b156bb 1655 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_swap( &R->X, &RP.X, b ) );
rahul_dahiya 0:fb8047b156bb 1656 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_swap( &R->Z, &RP.Z, b ) );
rahul_dahiya 0:fb8047b156bb 1657 MBEDTLS_MPI_CHK( ecp_double_add_mxz( grp, R, &RP, R, &RP, &PX ) );
rahul_dahiya 0:fb8047b156bb 1658 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_swap( &R->X, &RP.X, b ) );
rahul_dahiya 0:fb8047b156bb 1659 MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_swap( &R->Z, &RP.Z, b ) );
rahul_dahiya 0:fb8047b156bb 1660 }
rahul_dahiya 0:fb8047b156bb 1661
rahul_dahiya 0:fb8047b156bb 1662 MBEDTLS_MPI_CHK( ecp_normalize_mxz( grp, R ) );
rahul_dahiya 0:fb8047b156bb 1663
rahul_dahiya 0:fb8047b156bb 1664 cleanup:
rahul_dahiya 0:fb8047b156bb 1665 mbedtls_ecp_point_free( &RP ); mbedtls_mpi_free( &PX );
rahul_dahiya 0:fb8047b156bb 1666
rahul_dahiya 0:fb8047b156bb 1667 return( ret );
rahul_dahiya 0:fb8047b156bb 1668 }
rahul_dahiya 0:fb8047b156bb 1669
rahul_dahiya 0:fb8047b156bb 1670 #endif /* ECP_MONTGOMERY */
rahul_dahiya 0:fb8047b156bb 1671
rahul_dahiya 0:fb8047b156bb 1672 /*
rahul_dahiya 0:fb8047b156bb 1673 * Multiplication R = m * P
rahul_dahiya 0:fb8047b156bb 1674 */
rahul_dahiya 0:fb8047b156bb 1675 int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1676 const mbedtls_mpi *m, const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 1677 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
rahul_dahiya 0:fb8047b156bb 1678 {
rahul_dahiya 0:fb8047b156bb 1679 int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
rahul_dahiya 0:fb8047b156bb 1680 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
rahul_dahiya 0:fb8047b156bb 1681 char is_grp_capable = 0;
rahul_dahiya 0:fb8047b156bb 1682 #endif
rahul_dahiya 0:fb8047b156bb 1683
rahul_dahiya 0:fb8047b156bb 1684 /* Common sanity checks */
rahul_dahiya 0:fb8047b156bb 1685 if( mbedtls_mpi_cmp_int( &P->Z, 1 ) != 0 )
rahul_dahiya 0:fb8047b156bb 1686 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 1687
rahul_dahiya 0:fb8047b156bb 1688 if( ( ret = mbedtls_ecp_check_privkey( grp, m ) ) != 0 ||
rahul_dahiya 0:fb8047b156bb 1689 ( ret = mbedtls_ecp_check_pubkey( grp, P ) ) != 0 )
rahul_dahiya 0:fb8047b156bb 1690 return( ret );
rahul_dahiya 0:fb8047b156bb 1691
rahul_dahiya 0:fb8047b156bb 1692 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
rahul_dahiya 0:fb8047b156bb 1693 if ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1694 {
rahul_dahiya 0:fb8047b156bb 1695 MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) );
rahul_dahiya 0:fb8047b156bb 1696 }
rahul_dahiya 0:fb8047b156bb 1697
rahul_dahiya 0:fb8047b156bb 1698 #endif /* MBEDTLS_ECP_INTERNAL_ALT */
rahul_dahiya 0:fb8047b156bb 1699 #if defined(ECP_MONTGOMERY)
rahul_dahiya 0:fb8047b156bb 1700 if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
rahul_dahiya 0:fb8047b156bb 1701 ret = ecp_mul_mxz( grp, R, m, P, f_rng, p_rng );
rahul_dahiya 0:fb8047b156bb 1702
rahul_dahiya 0:fb8047b156bb 1703 #endif
rahul_dahiya 0:fb8047b156bb 1704 #if defined(ECP_SHORTWEIERSTRASS)
rahul_dahiya 0:fb8047b156bb 1705 if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
rahul_dahiya 0:fb8047b156bb 1706 ret = ecp_mul_comb( grp, R, m, P, f_rng, p_rng );
rahul_dahiya 0:fb8047b156bb 1707
rahul_dahiya 0:fb8047b156bb 1708 #endif
rahul_dahiya 0:fb8047b156bb 1709 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
rahul_dahiya 0:fb8047b156bb 1710 cleanup:
rahul_dahiya 0:fb8047b156bb 1711
rahul_dahiya 0:fb8047b156bb 1712 if ( is_grp_capable )
rahul_dahiya 0:fb8047b156bb 1713 {
rahul_dahiya 0:fb8047b156bb 1714 mbedtls_internal_ecp_free( grp );
rahul_dahiya 0:fb8047b156bb 1715 }
rahul_dahiya 0:fb8047b156bb 1716
rahul_dahiya 0:fb8047b156bb 1717 #endif /* MBEDTLS_ECP_INTERNAL_ALT */
rahul_dahiya 0:fb8047b156bb 1718 return( ret );
rahul_dahiya 0:fb8047b156bb 1719 }
rahul_dahiya 0:fb8047b156bb 1720
rahul_dahiya 0:fb8047b156bb 1721 #if defined(ECP_SHORTWEIERSTRASS)
rahul_dahiya 0:fb8047b156bb 1722 /*
rahul_dahiya 0:fb8047b156bb 1723 * Check that an affine point is valid as a public key,
rahul_dahiya 0:fb8047b156bb 1724 * short weierstrass curves (SEC1 3.2.3.1)
rahul_dahiya 0:fb8047b156bb 1725 */
rahul_dahiya 0:fb8047b156bb 1726 static int ecp_check_pubkey_sw( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 1727 {
rahul_dahiya 0:fb8047b156bb 1728 int ret;
rahul_dahiya 0:fb8047b156bb 1729 mbedtls_mpi YY, RHS;
rahul_dahiya 0:fb8047b156bb 1730
rahul_dahiya 0:fb8047b156bb 1731 /* pt coordinates must be normalized for our checks */
rahul_dahiya 0:fb8047b156bb 1732 if( mbedtls_mpi_cmp_int( &pt->X, 0 ) < 0 ||
rahul_dahiya 0:fb8047b156bb 1733 mbedtls_mpi_cmp_int( &pt->Y, 0 ) < 0 ||
rahul_dahiya 0:fb8047b156bb 1734 mbedtls_mpi_cmp_mpi( &pt->X, &grp->P ) >= 0 ||
rahul_dahiya 0:fb8047b156bb 1735 mbedtls_mpi_cmp_mpi( &pt->Y, &grp->P ) >= 0 )
rahul_dahiya 0:fb8047b156bb 1736 return( MBEDTLS_ERR_ECP_INVALID_KEY );
rahul_dahiya 0:fb8047b156bb 1737
rahul_dahiya 0:fb8047b156bb 1738 mbedtls_mpi_init( &YY ); mbedtls_mpi_init( &RHS );
rahul_dahiya 0:fb8047b156bb 1739
rahul_dahiya 0:fb8047b156bb 1740 /*
rahul_dahiya 0:fb8047b156bb 1741 * YY = Y^2
rahul_dahiya 0:fb8047b156bb 1742 * RHS = X (X^2 + A) + B = X^3 + A X + B
rahul_dahiya 0:fb8047b156bb 1743 */
rahul_dahiya 0:fb8047b156bb 1744 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &YY, &pt->Y, &pt->Y ) ); MOD_MUL( YY );
rahul_dahiya 0:fb8047b156bb 1745 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &RHS, &pt->X, &pt->X ) ); MOD_MUL( RHS );
rahul_dahiya 0:fb8047b156bb 1746
rahul_dahiya 0:fb8047b156bb 1747 /* Special case for A = -3 */
rahul_dahiya 0:fb8047b156bb 1748 if( grp->A.p == NULL )
rahul_dahiya 0:fb8047b156bb 1749 {
rahul_dahiya 0:fb8047b156bb 1750 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &RHS, &RHS, 3 ) ); MOD_SUB( RHS );
rahul_dahiya 0:fb8047b156bb 1751 }
rahul_dahiya 0:fb8047b156bb 1752 else
rahul_dahiya 0:fb8047b156bb 1753 {
rahul_dahiya 0:fb8047b156bb 1754 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &RHS, &RHS, &grp->A ) ); MOD_ADD( RHS );
rahul_dahiya 0:fb8047b156bb 1755 }
rahul_dahiya 0:fb8047b156bb 1756
rahul_dahiya 0:fb8047b156bb 1757 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &RHS, &RHS, &pt->X ) ); MOD_MUL( RHS );
rahul_dahiya 0:fb8047b156bb 1758 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &RHS, &RHS, &grp->B ) ); MOD_ADD( RHS );
rahul_dahiya 0:fb8047b156bb 1759
rahul_dahiya 0:fb8047b156bb 1760 if( mbedtls_mpi_cmp_mpi( &YY, &RHS ) != 0 )
rahul_dahiya 0:fb8047b156bb 1761 ret = MBEDTLS_ERR_ECP_INVALID_KEY;
rahul_dahiya 0:fb8047b156bb 1762
rahul_dahiya 0:fb8047b156bb 1763 cleanup:
rahul_dahiya 0:fb8047b156bb 1764
rahul_dahiya 0:fb8047b156bb 1765 mbedtls_mpi_free( &YY ); mbedtls_mpi_free( &RHS );
rahul_dahiya 0:fb8047b156bb 1766
rahul_dahiya 0:fb8047b156bb 1767 return( ret );
rahul_dahiya 0:fb8047b156bb 1768 }
rahul_dahiya 0:fb8047b156bb 1769 #endif /* ECP_SHORTWEIERSTRASS */
rahul_dahiya 0:fb8047b156bb 1770
rahul_dahiya 0:fb8047b156bb 1771 /*
rahul_dahiya 0:fb8047b156bb 1772 * R = m * P with shortcuts for m == 1 and m == -1
rahul_dahiya 0:fb8047b156bb 1773 * NOT constant-time - ONLY for short Weierstrass!
rahul_dahiya 0:fb8047b156bb 1774 */
rahul_dahiya 0:fb8047b156bb 1775 static int mbedtls_ecp_mul_shortcuts( mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 1776 mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1777 const mbedtls_mpi *m,
rahul_dahiya 0:fb8047b156bb 1778 const mbedtls_ecp_point *P )
rahul_dahiya 0:fb8047b156bb 1779 {
rahul_dahiya 0:fb8047b156bb 1780 int ret;
rahul_dahiya 0:fb8047b156bb 1781
rahul_dahiya 0:fb8047b156bb 1782 if( mbedtls_mpi_cmp_int( m, 1 ) == 0 )
rahul_dahiya 0:fb8047b156bb 1783 {
rahul_dahiya 0:fb8047b156bb 1784 MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, P ) );
rahul_dahiya 0:fb8047b156bb 1785 }
rahul_dahiya 0:fb8047b156bb 1786 else if( mbedtls_mpi_cmp_int( m, -1 ) == 0 )
rahul_dahiya 0:fb8047b156bb 1787 {
rahul_dahiya 0:fb8047b156bb 1788 MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, P ) );
rahul_dahiya 0:fb8047b156bb 1789 if( mbedtls_mpi_cmp_int( &R->Y, 0 ) != 0 )
rahul_dahiya 0:fb8047b156bb 1790 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &R->Y, &grp->P, &R->Y ) );
rahul_dahiya 0:fb8047b156bb 1791 }
rahul_dahiya 0:fb8047b156bb 1792 else
rahul_dahiya 0:fb8047b156bb 1793 {
rahul_dahiya 0:fb8047b156bb 1794 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R, m, P, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 1795 }
rahul_dahiya 0:fb8047b156bb 1796
rahul_dahiya 0:fb8047b156bb 1797 cleanup:
rahul_dahiya 0:fb8047b156bb 1798 return( ret );
rahul_dahiya 0:fb8047b156bb 1799 }
rahul_dahiya 0:fb8047b156bb 1800
rahul_dahiya 0:fb8047b156bb 1801 /*
rahul_dahiya 0:fb8047b156bb 1802 * Linear combination
rahul_dahiya 0:fb8047b156bb 1803 * NOT constant-time
rahul_dahiya 0:fb8047b156bb 1804 */
rahul_dahiya 0:fb8047b156bb 1805 int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
rahul_dahiya 0:fb8047b156bb 1806 const mbedtls_mpi *m, const mbedtls_ecp_point *P,
rahul_dahiya 0:fb8047b156bb 1807 const mbedtls_mpi *n, const mbedtls_ecp_point *Q )
rahul_dahiya 0:fb8047b156bb 1808 {
rahul_dahiya 0:fb8047b156bb 1809 int ret;
rahul_dahiya 0:fb8047b156bb 1810 mbedtls_ecp_point mP;
rahul_dahiya 0:fb8047b156bb 1811 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
rahul_dahiya 0:fb8047b156bb 1812 char is_grp_capable = 0;
rahul_dahiya 0:fb8047b156bb 1813 #endif
rahul_dahiya 0:fb8047b156bb 1814
rahul_dahiya 0:fb8047b156bb 1815 if( ecp_get_type( grp ) != ECP_TYPE_SHORT_WEIERSTRASS )
rahul_dahiya 0:fb8047b156bb 1816 return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
rahul_dahiya 0:fb8047b156bb 1817
rahul_dahiya 0:fb8047b156bb 1818 mbedtls_ecp_point_init( &mP );
rahul_dahiya 0:fb8047b156bb 1819
rahul_dahiya 0:fb8047b156bb 1820 MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, &mP, m, P ) );
rahul_dahiya 0:fb8047b156bb 1821 MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, R, n, Q ) );
rahul_dahiya 0:fb8047b156bb 1822
rahul_dahiya 0:fb8047b156bb 1823 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
rahul_dahiya 0:fb8047b156bb 1824 if ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) )
rahul_dahiya 0:fb8047b156bb 1825 {
rahul_dahiya 0:fb8047b156bb 1826 MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) );
rahul_dahiya 0:fb8047b156bb 1827 }
rahul_dahiya 0:fb8047b156bb 1828
rahul_dahiya 0:fb8047b156bb 1829 #endif /* MBEDTLS_ECP_INTERNAL_ALT */
rahul_dahiya 0:fb8047b156bb 1830 MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, &mP, R ) );
rahul_dahiya 0:fb8047b156bb 1831 MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) );
rahul_dahiya 0:fb8047b156bb 1832
rahul_dahiya 0:fb8047b156bb 1833 cleanup:
rahul_dahiya 0:fb8047b156bb 1834
rahul_dahiya 0:fb8047b156bb 1835 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
rahul_dahiya 0:fb8047b156bb 1836 if ( is_grp_capable )
rahul_dahiya 0:fb8047b156bb 1837 {
rahul_dahiya 0:fb8047b156bb 1838 mbedtls_internal_ecp_free( grp );
rahul_dahiya 0:fb8047b156bb 1839 }
rahul_dahiya 0:fb8047b156bb 1840
rahul_dahiya 0:fb8047b156bb 1841 #endif /* MBEDTLS_ECP_INTERNAL_ALT */
rahul_dahiya 0:fb8047b156bb 1842 mbedtls_ecp_point_free( &mP );
rahul_dahiya 0:fb8047b156bb 1843
rahul_dahiya 0:fb8047b156bb 1844 return( ret );
rahul_dahiya 0:fb8047b156bb 1845 }
rahul_dahiya 0:fb8047b156bb 1846
rahul_dahiya 0:fb8047b156bb 1847
rahul_dahiya 0:fb8047b156bb 1848 #if defined(ECP_MONTGOMERY)
rahul_dahiya 0:fb8047b156bb 1849 /*
rahul_dahiya 0:fb8047b156bb 1850 * Check validity of a public key for Montgomery curves with x-only schemes
rahul_dahiya 0:fb8047b156bb 1851 */
rahul_dahiya 0:fb8047b156bb 1852 static int ecp_check_pubkey_mx( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 1853 {
rahul_dahiya 0:fb8047b156bb 1854 /* [Curve25519 p. 5] Just check X is the correct number of bytes */
rahul_dahiya 0:fb8047b156bb 1855 if( mbedtls_mpi_size( &pt->X ) > ( grp->nbits + 7 ) / 8 )
rahul_dahiya 0:fb8047b156bb 1856 return( MBEDTLS_ERR_ECP_INVALID_KEY );
rahul_dahiya 0:fb8047b156bb 1857
rahul_dahiya 0:fb8047b156bb 1858 return( 0 );
rahul_dahiya 0:fb8047b156bb 1859 }
rahul_dahiya 0:fb8047b156bb 1860 #endif /* ECP_MONTGOMERY */
rahul_dahiya 0:fb8047b156bb 1861
rahul_dahiya 0:fb8047b156bb 1862 /*
rahul_dahiya 0:fb8047b156bb 1863 * Check that a point is valid as a public key
rahul_dahiya 0:fb8047b156bb 1864 */
rahul_dahiya 0:fb8047b156bb 1865 int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt )
rahul_dahiya 0:fb8047b156bb 1866 {
rahul_dahiya 0:fb8047b156bb 1867 /* Must use affine coordinates */
rahul_dahiya 0:fb8047b156bb 1868 if( mbedtls_mpi_cmp_int( &pt->Z, 1 ) != 0 )
rahul_dahiya 0:fb8047b156bb 1869 return( MBEDTLS_ERR_ECP_INVALID_KEY );
rahul_dahiya 0:fb8047b156bb 1870
rahul_dahiya 0:fb8047b156bb 1871 #if defined(ECP_MONTGOMERY)
rahul_dahiya 0:fb8047b156bb 1872 if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
rahul_dahiya 0:fb8047b156bb 1873 return( ecp_check_pubkey_mx( grp, pt ) );
rahul_dahiya 0:fb8047b156bb 1874 #endif
rahul_dahiya 0:fb8047b156bb 1875 #if defined(ECP_SHORTWEIERSTRASS)
rahul_dahiya 0:fb8047b156bb 1876 if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
rahul_dahiya 0:fb8047b156bb 1877 return( ecp_check_pubkey_sw( grp, pt ) );
rahul_dahiya 0:fb8047b156bb 1878 #endif
rahul_dahiya 0:fb8047b156bb 1879 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 1880 }
rahul_dahiya 0:fb8047b156bb 1881
rahul_dahiya 0:fb8047b156bb 1882 /*
rahul_dahiya 0:fb8047b156bb 1883 * Check that an mbedtls_mpi is valid as a private key
rahul_dahiya 0:fb8047b156bb 1884 */
rahul_dahiya 0:fb8047b156bb 1885 int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi *d )
rahul_dahiya 0:fb8047b156bb 1886 {
rahul_dahiya 0:fb8047b156bb 1887 #if defined(ECP_MONTGOMERY)
rahul_dahiya 0:fb8047b156bb 1888 if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
rahul_dahiya 0:fb8047b156bb 1889 {
rahul_dahiya 0:fb8047b156bb 1890 /* see [Curve25519] page 5 */
rahul_dahiya 0:fb8047b156bb 1891 if( mbedtls_mpi_get_bit( d, 0 ) != 0 ||
rahul_dahiya 0:fb8047b156bb 1892 mbedtls_mpi_get_bit( d, 1 ) != 0 ||
rahul_dahiya 0:fb8047b156bb 1893 mbedtls_mpi_get_bit( d, 2 ) != 0 ||
rahul_dahiya 0:fb8047b156bb 1894 mbedtls_mpi_bitlen( d ) - 1 != grp->nbits ) /* mbedtls_mpi_bitlen is one-based! */
rahul_dahiya 0:fb8047b156bb 1895 return( MBEDTLS_ERR_ECP_INVALID_KEY );
rahul_dahiya 0:fb8047b156bb 1896 else
rahul_dahiya 0:fb8047b156bb 1897 return( 0 );
rahul_dahiya 0:fb8047b156bb 1898 }
rahul_dahiya 0:fb8047b156bb 1899 #endif /* ECP_MONTGOMERY */
rahul_dahiya 0:fb8047b156bb 1900 #if defined(ECP_SHORTWEIERSTRASS)
rahul_dahiya 0:fb8047b156bb 1901 if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
rahul_dahiya 0:fb8047b156bb 1902 {
rahul_dahiya 0:fb8047b156bb 1903 /* see SEC1 3.2 */
rahul_dahiya 0:fb8047b156bb 1904 if( mbedtls_mpi_cmp_int( d, 1 ) < 0 ||
rahul_dahiya 0:fb8047b156bb 1905 mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 )
rahul_dahiya 0:fb8047b156bb 1906 return( MBEDTLS_ERR_ECP_INVALID_KEY );
rahul_dahiya 0:fb8047b156bb 1907 else
rahul_dahiya 0:fb8047b156bb 1908 return( 0 );
rahul_dahiya 0:fb8047b156bb 1909 }
rahul_dahiya 0:fb8047b156bb 1910 #endif /* ECP_SHORTWEIERSTRASS */
rahul_dahiya 0:fb8047b156bb 1911
rahul_dahiya 0:fb8047b156bb 1912 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 1913 }
rahul_dahiya 0:fb8047b156bb 1914
rahul_dahiya 0:fb8047b156bb 1915 /*
rahul_dahiya 0:fb8047b156bb 1916 * Generate a keypair with configurable base point
rahul_dahiya 0:fb8047b156bb 1917 */
rahul_dahiya 0:fb8047b156bb 1918 int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 1919 const mbedtls_ecp_point *G,
rahul_dahiya 0:fb8047b156bb 1920 mbedtls_mpi *d, mbedtls_ecp_point *Q,
rahul_dahiya 0:fb8047b156bb 1921 int (*f_rng)(void *, unsigned char *, size_t),
rahul_dahiya 0:fb8047b156bb 1922 void *p_rng )
rahul_dahiya 0:fb8047b156bb 1923 {
rahul_dahiya 0:fb8047b156bb 1924 int ret;
rahul_dahiya 0:fb8047b156bb 1925 size_t n_size = ( grp->nbits + 7 ) / 8;
rahul_dahiya 0:fb8047b156bb 1926
rahul_dahiya 0:fb8047b156bb 1927 #if defined(ECP_MONTGOMERY)
rahul_dahiya 0:fb8047b156bb 1928 if( ecp_get_type( grp ) == ECP_TYPE_MONTGOMERY )
rahul_dahiya 0:fb8047b156bb 1929 {
rahul_dahiya 0:fb8047b156bb 1930 /* [M225] page 5 */
rahul_dahiya 0:fb8047b156bb 1931 size_t b;
rahul_dahiya 0:fb8047b156bb 1932
rahul_dahiya 0:fb8047b156bb 1933 do {
rahul_dahiya 0:fb8047b156bb 1934 MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( d, n_size, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1935 } while( mbedtls_mpi_bitlen( d ) == 0);
rahul_dahiya 0:fb8047b156bb 1936
rahul_dahiya 0:fb8047b156bb 1937 /* Make sure the most significant bit is nbits */
rahul_dahiya 0:fb8047b156bb 1938 b = mbedtls_mpi_bitlen( d ) - 1; /* mbedtls_mpi_bitlen is one-based */
rahul_dahiya 0:fb8047b156bb 1939 if( b > grp->nbits )
rahul_dahiya 0:fb8047b156bb 1940 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, b - grp->nbits ) );
rahul_dahiya 0:fb8047b156bb 1941 else
rahul_dahiya 0:fb8047b156bb 1942 MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, grp->nbits, 1 ) );
rahul_dahiya 0:fb8047b156bb 1943
rahul_dahiya 0:fb8047b156bb 1944 /* Make sure the last three bits are unset */
rahul_dahiya 0:fb8047b156bb 1945 MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 0, 0 ) );
rahul_dahiya 0:fb8047b156bb 1946 MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 1, 0 ) );
rahul_dahiya 0:fb8047b156bb 1947 MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 2, 0 ) );
rahul_dahiya 0:fb8047b156bb 1948 }
rahul_dahiya 0:fb8047b156bb 1949 else
rahul_dahiya 0:fb8047b156bb 1950 #endif /* ECP_MONTGOMERY */
rahul_dahiya 0:fb8047b156bb 1951 #if defined(ECP_SHORTWEIERSTRASS)
rahul_dahiya 0:fb8047b156bb 1952 if( ecp_get_type( grp ) == ECP_TYPE_SHORT_WEIERSTRASS )
rahul_dahiya 0:fb8047b156bb 1953 {
rahul_dahiya 0:fb8047b156bb 1954 /* SEC1 3.2.1: Generate d such that 1 <= n < N */
rahul_dahiya 0:fb8047b156bb 1955 int count = 0;
rahul_dahiya 0:fb8047b156bb 1956 unsigned char rnd[MBEDTLS_ECP_MAX_BYTES];
rahul_dahiya 0:fb8047b156bb 1957
rahul_dahiya 0:fb8047b156bb 1958 /*
rahul_dahiya 0:fb8047b156bb 1959 * Match the procedure given in RFC 6979 (deterministic ECDSA):
rahul_dahiya 0:fb8047b156bb 1960 * - use the same byte ordering;
rahul_dahiya 0:fb8047b156bb 1961 * - keep the leftmost nbits bits of the generated octet string;
rahul_dahiya 0:fb8047b156bb 1962 * - try until result is in the desired range.
rahul_dahiya 0:fb8047b156bb 1963 * This also avoids any biais, which is especially important for ECDSA.
rahul_dahiya 0:fb8047b156bb 1964 */
rahul_dahiya 0:fb8047b156bb 1965 do
rahul_dahiya 0:fb8047b156bb 1966 {
rahul_dahiya 0:fb8047b156bb 1967 MBEDTLS_MPI_CHK( f_rng( p_rng, rnd, n_size ) );
rahul_dahiya 0:fb8047b156bb 1968 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( d, rnd, n_size ) );
rahul_dahiya 0:fb8047b156bb 1969 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, 8 * n_size - grp->nbits ) );
rahul_dahiya 0:fb8047b156bb 1970
rahul_dahiya 0:fb8047b156bb 1971 /*
rahul_dahiya 0:fb8047b156bb 1972 * Each try has at worst a probability 1/2 of failing (the msb has
rahul_dahiya 0:fb8047b156bb 1973 * a probability 1/2 of being 0, and then the result will be < N),
rahul_dahiya 0:fb8047b156bb 1974 * so after 30 tries failure probability is a most 2**(-30).
rahul_dahiya 0:fb8047b156bb 1975 *
rahul_dahiya 0:fb8047b156bb 1976 * For most curves, 1 try is enough with overwhelming probability,
rahul_dahiya 0:fb8047b156bb 1977 * since N starts with a lot of 1s in binary, but some curves
rahul_dahiya 0:fb8047b156bb 1978 * such as secp224k1 are actually very close to the worst case.
rahul_dahiya 0:fb8047b156bb 1979 */
rahul_dahiya 0:fb8047b156bb 1980 if( ++count > 30 )
rahul_dahiya 0:fb8047b156bb 1981 return( MBEDTLS_ERR_ECP_RANDOM_FAILED );
rahul_dahiya 0:fb8047b156bb 1982 }
rahul_dahiya 0:fb8047b156bb 1983 while( mbedtls_mpi_cmp_int( d, 1 ) < 0 ||
rahul_dahiya 0:fb8047b156bb 1984 mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 );
rahul_dahiya 0:fb8047b156bb 1985 }
rahul_dahiya 0:fb8047b156bb 1986 else
rahul_dahiya 0:fb8047b156bb 1987 #endif /* ECP_SHORTWEIERSTRASS */
rahul_dahiya 0:fb8047b156bb 1988 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 1989
rahul_dahiya 0:fb8047b156bb 1990 cleanup:
rahul_dahiya 0:fb8047b156bb 1991 if( ret != 0 )
rahul_dahiya 0:fb8047b156bb 1992 return( ret );
rahul_dahiya 0:fb8047b156bb 1993
rahul_dahiya 0:fb8047b156bb 1994 return( mbedtls_ecp_mul( grp, Q, d, G, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 1995 }
rahul_dahiya 0:fb8047b156bb 1996
rahul_dahiya 0:fb8047b156bb 1997 /*
rahul_dahiya 0:fb8047b156bb 1998 * Generate key pair, wrapper for conventional base point
rahul_dahiya 0:fb8047b156bb 1999 */
rahul_dahiya 0:fb8047b156bb 2000 int mbedtls_ecp_gen_keypair( mbedtls_ecp_group *grp,
rahul_dahiya 0:fb8047b156bb 2001 mbedtls_mpi *d, mbedtls_ecp_point *Q,
rahul_dahiya 0:fb8047b156bb 2002 int (*f_rng)(void *, unsigned char *, size_t),
rahul_dahiya 0:fb8047b156bb 2003 void *p_rng )
rahul_dahiya 0:fb8047b156bb 2004 {
rahul_dahiya 0:fb8047b156bb 2005 return( mbedtls_ecp_gen_keypair_base( grp, &grp->G, d, Q, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 2006 }
rahul_dahiya 0:fb8047b156bb 2007
rahul_dahiya 0:fb8047b156bb 2008 /*
rahul_dahiya 0:fb8047b156bb 2009 * Generate a keypair, prettier wrapper
rahul_dahiya 0:fb8047b156bb 2010 */
rahul_dahiya 0:fb8047b156bb 2011 int mbedtls_ecp_gen_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
rahul_dahiya 0:fb8047b156bb 2012 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
rahul_dahiya 0:fb8047b156bb 2013 {
rahul_dahiya 0:fb8047b156bb 2014 int ret;
rahul_dahiya 0:fb8047b156bb 2015
rahul_dahiya 0:fb8047b156bb 2016 if( ( ret = mbedtls_ecp_group_load( &key->grp, grp_id ) ) != 0 )
rahul_dahiya 0:fb8047b156bb 2017 return( ret );
rahul_dahiya 0:fb8047b156bb 2018
rahul_dahiya 0:fb8047b156bb 2019 return( mbedtls_ecp_gen_keypair( &key->grp, &key->d, &key->Q, f_rng, p_rng ) );
rahul_dahiya 0:fb8047b156bb 2020 }
rahul_dahiya 0:fb8047b156bb 2021
rahul_dahiya 0:fb8047b156bb 2022 /*
rahul_dahiya 0:fb8047b156bb 2023 * Check a public-private key pair
rahul_dahiya 0:fb8047b156bb 2024 */
rahul_dahiya 0:fb8047b156bb 2025 int mbedtls_ecp_check_pub_priv( const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv )
rahul_dahiya 0:fb8047b156bb 2026 {
rahul_dahiya 0:fb8047b156bb 2027 int ret;
rahul_dahiya 0:fb8047b156bb 2028 mbedtls_ecp_point Q;
rahul_dahiya 0:fb8047b156bb 2029 mbedtls_ecp_group grp;
rahul_dahiya 0:fb8047b156bb 2030
rahul_dahiya 0:fb8047b156bb 2031 if( pub->grp.id == MBEDTLS_ECP_DP_NONE ||
rahul_dahiya 0:fb8047b156bb 2032 pub->grp.id != prv->grp.id ||
rahul_dahiya 0:fb8047b156bb 2033 mbedtls_mpi_cmp_mpi( &pub->Q.X, &prv->Q.X ) ||
rahul_dahiya 0:fb8047b156bb 2034 mbedtls_mpi_cmp_mpi( &pub->Q.Y, &prv->Q.Y ) ||
rahul_dahiya 0:fb8047b156bb 2035 mbedtls_mpi_cmp_mpi( &pub->Q.Z, &prv->Q.Z ) )
rahul_dahiya 0:fb8047b156bb 2036 {
rahul_dahiya 0:fb8047b156bb 2037 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
rahul_dahiya 0:fb8047b156bb 2038 }
rahul_dahiya 0:fb8047b156bb 2039
rahul_dahiya 0:fb8047b156bb 2040 mbedtls_ecp_point_init( &Q );
rahul_dahiya 0:fb8047b156bb 2041 mbedtls_ecp_group_init( &grp );
rahul_dahiya 0:fb8047b156bb 2042
rahul_dahiya 0:fb8047b156bb 2043 /* mbedtls_ecp_mul() needs a non-const group... */
rahul_dahiya 0:fb8047b156bb 2044 mbedtls_ecp_group_copy( &grp, &prv->grp );
rahul_dahiya 0:fb8047b156bb 2045
rahul_dahiya 0:fb8047b156bb 2046 /* Also checks d is valid */
rahul_dahiya 0:fb8047b156bb 2047 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &Q, &prv->d, &prv->grp.G, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 2048
rahul_dahiya 0:fb8047b156bb 2049 if( mbedtls_mpi_cmp_mpi( &Q.X, &prv->Q.X ) ||
rahul_dahiya 0:fb8047b156bb 2050 mbedtls_mpi_cmp_mpi( &Q.Y, &prv->Q.Y ) ||
rahul_dahiya 0:fb8047b156bb 2051 mbedtls_mpi_cmp_mpi( &Q.Z, &prv->Q.Z ) )
rahul_dahiya 0:fb8047b156bb 2052 {
rahul_dahiya 0:fb8047b156bb 2053 ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
rahul_dahiya 0:fb8047b156bb 2054 goto cleanup;
rahul_dahiya 0:fb8047b156bb 2055 }
rahul_dahiya 0:fb8047b156bb 2056
rahul_dahiya 0:fb8047b156bb 2057 cleanup:
rahul_dahiya 0:fb8047b156bb 2058 mbedtls_ecp_point_free( &Q );
rahul_dahiya 0:fb8047b156bb 2059 mbedtls_ecp_group_free( &grp );
rahul_dahiya 0:fb8047b156bb 2060
rahul_dahiya 0:fb8047b156bb 2061 return( ret );
rahul_dahiya 0:fb8047b156bb 2062 }
rahul_dahiya 0:fb8047b156bb 2063
rahul_dahiya 0:fb8047b156bb 2064 #if defined(MBEDTLS_SELF_TEST)
rahul_dahiya 0:fb8047b156bb 2065
rahul_dahiya 0:fb8047b156bb 2066 /*
rahul_dahiya 0:fb8047b156bb 2067 * Checkup routine
rahul_dahiya 0:fb8047b156bb 2068 */
rahul_dahiya 0:fb8047b156bb 2069 int mbedtls_ecp_self_test( int verbose )
rahul_dahiya 0:fb8047b156bb 2070 {
rahul_dahiya 0:fb8047b156bb 2071 int ret;
rahul_dahiya 0:fb8047b156bb 2072 size_t i;
rahul_dahiya 0:fb8047b156bb 2073 mbedtls_ecp_group grp;
rahul_dahiya 0:fb8047b156bb 2074 mbedtls_ecp_point R, P;
rahul_dahiya 0:fb8047b156bb 2075 mbedtls_mpi m;
rahul_dahiya 0:fb8047b156bb 2076 unsigned long add_c_prev, dbl_c_prev, mul_c_prev;
rahul_dahiya 0:fb8047b156bb 2077 /* exponents especially adapted for secp192r1 */
rahul_dahiya 0:fb8047b156bb 2078 const char *exponents[] =
rahul_dahiya 0:fb8047b156bb 2079 {
rahul_dahiya 0:fb8047b156bb 2080 "000000000000000000000000000000000000000000000001", /* one */
rahul_dahiya 0:fb8047b156bb 2081 "FFFFFFFFFFFFFFFFFFFFFFFF99DEF836146BC9B1B4D22830", /* N - 1 */
rahul_dahiya 0:fb8047b156bb 2082 "5EA6F389A38B8BC81E767753B15AA5569E1782E30ABE7D25", /* random */
rahul_dahiya 0:fb8047b156bb 2083 "400000000000000000000000000000000000000000000000", /* one and zeros */
rahul_dahiya 0:fb8047b156bb 2084 "7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", /* all ones */
rahul_dahiya 0:fb8047b156bb 2085 "555555555555555555555555555555555555555555555555", /* 101010... */
rahul_dahiya 0:fb8047b156bb 2086 };
rahul_dahiya 0:fb8047b156bb 2087
rahul_dahiya 0:fb8047b156bb 2088 mbedtls_ecp_group_init( &grp );
rahul_dahiya 0:fb8047b156bb 2089 mbedtls_ecp_point_init( &R );
rahul_dahiya 0:fb8047b156bb 2090 mbedtls_ecp_point_init( &P );
rahul_dahiya 0:fb8047b156bb 2091 mbedtls_mpi_init( &m );
rahul_dahiya 0:fb8047b156bb 2092
rahul_dahiya 0:fb8047b156bb 2093 /* Use secp192r1 if available, or any available curve */
rahul_dahiya 0:fb8047b156bb 2094 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
rahul_dahiya 0:fb8047b156bb 2095 MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, MBEDTLS_ECP_DP_SECP192R1 ) );
rahul_dahiya 0:fb8047b156bb 2096 #else
rahul_dahiya 0:fb8047b156bb 2097 MBEDTLS_MPI_CHK( mbedtls_ecp_group_load( &grp, mbedtls_ecp_curve_list()->grp_id ) );
rahul_dahiya 0:fb8047b156bb 2098 #endif
rahul_dahiya 0:fb8047b156bb 2099
rahul_dahiya 0:fb8047b156bb 2100 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2101 mbedtls_printf( " ECP test #1 (constant op_count, base point G): " );
rahul_dahiya 0:fb8047b156bb 2102
rahul_dahiya 0:fb8047b156bb 2103 /* Do a dummy multiplication first to trigger precomputation */
rahul_dahiya 0:fb8047b156bb 2104 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &m, 2 ) );
rahul_dahiya 0:fb8047b156bb 2105 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &P, &m, &grp.G, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 2106
rahul_dahiya 0:fb8047b156bb 2107 add_count = 0;
rahul_dahiya 0:fb8047b156bb 2108 dbl_count = 0;
rahul_dahiya 0:fb8047b156bb 2109 mul_count = 0;
rahul_dahiya 0:fb8047b156bb 2110 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[0] ) );
rahul_dahiya 0:fb8047b156bb 2111 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &grp.G, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 2112
rahul_dahiya 0:fb8047b156bb 2113 for( i = 1; i < sizeof( exponents ) / sizeof( exponents[0] ); i++ )
rahul_dahiya 0:fb8047b156bb 2114 {
rahul_dahiya 0:fb8047b156bb 2115 add_c_prev = add_count;
rahul_dahiya 0:fb8047b156bb 2116 dbl_c_prev = dbl_count;
rahul_dahiya 0:fb8047b156bb 2117 mul_c_prev = mul_count;
rahul_dahiya 0:fb8047b156bb 2118 add_count = 0;
rahul_dahiya 0:fb8047b156bb 2119 dbl_count = 0;
rahul_dahiya 0:fb8047b156bb 2120 mul_count = 0;
rahul_dahiya 0:fb8047b156bb 2121
rahul_dahiya 0:fb8047b156bb 2122 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[i] ) );
rahul_dahiya 0:fb8047b156bb 2123 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &grp.G, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 2124
rahul_dahiya 0:fb8047b156bb 2125 if( add_count != add_c_prev ||
rahul_dahiya 0:fb8047b156bb 2126 dbl_count != dbl_c_prev ||
rahul_dahiya 0:fb8047b156bb 2127 mul_count != mul_c_prev )
rahul_dahiya 0:fb8047b156bb 2128 {
rahul_dahiya 0:fb8047b156bb 2129 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2130 mbedtls_printf( "failed (%u)\n", (unsigned int) i );
rahul_dahiya 0:fb8047b156bb 2131
rahul_dahiya 0:fb8047b156bb 2132 ret = 1;
rahul_dahiya 0:fb8047b156bb 2133 goto cleanup;
rahul_dahiya 0:fb8047b156bb 2134 }
rahul_dahiya 0:fb8047b156bb 2135 }
rahul_dahiya 0:fb8047b156bb 2136
rahul_dahiya 0:fb8047b156bb 2137 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2138 mbedtls_printf( "passed\n" );
rahul_dahiya 0:fb8047b156bb 2139
rahul_dahiya 0:fb8047b156bb 2140 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2141 mbedtls_printf( " ECP test #2 (constant op_count, other point): " );
rahul_dahiya 0:fb8047b156bb 2142 /* We computed P = 2G last time, use it */
rahul_dahiya 0:fb8047b156bb 2143
rahul_dahiya 0:fb8047b156bb 2144 add_count = 0;
rahul_dahiya 0:fb8047b156bb 2145 dbl_count = 0;
rahul_dahiya 0:fb8047b156bb 2146 mul_count = 0;
rahul_dahiya 0:fb8047b156bb 2147 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[0] ) );
rahul_dahiya 0:fb8047b156bb 2148 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &P, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 2149
rahul_dahiya 0:fb8047b156bb 2150 for( i = 1; i < sizeof( exponents ) / sizeof( exponents[0] ); i++ )
rahul_dahiya 0:fb8047b156bb 2151 {
rahul_dahiya 0:fb8047b156bb 2152 add_c_prev = add_count;
rahul_dahiya 0:fb8047b156bb 2153 dbl_c_prev = dbl_count;
rahul_dahiya 0:fb8047b156bb 2154 mul_c_prev = mul_count;
rahul_dahiya 0:fb8047b156bb 2155 add_count = 0;
rahul_dahiya 0:fb8047b156bb 2156 dbl_count = 0;
rahul_dahiya 0:fb8047b156bb 2157 mul_count = 0;
rahul_dahiya 0:fb8047b156bb 2158
rahul_dahiya 0:fb8047b156bb 2159 MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &m, 16, exponents[i] ) );
rahul_dahiya 0:fb8047b156bb 2160 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( &grp, &R, &m, &P, NULL, NULL ) );
rahul_dahiya 0:fb8047b156bb 2161
rahul_dahiya 0:fb8047b156bb 2162 if( add_count != add_c_prev ||
rahul_dahiya 0:fb8047b156bb 2163 dbl_count != dbl_c_prev ||
rahul_dahiya 0:fb8047b156bb 2164 mul_count != mul_c_prev )
rahul_dahiya 0:fb8047b156bb 2165 {
rahul_dahiya 0:fb8047b156bb 2166 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2167 mbedtls_printf( "failed (%u)\n", (unsigned int) i );
rahul_dahiya 0:fb8047b156bb 2168
rahul_dahiya 0:fb8047b156bb 2169 ret = 1;
rahul_dahiya 0:fb8047b156bb 2170 goto cleanup;
rahul_dahiya 0:fb8047b156bb 2171 }
rahul_dahiya 0:fb8047b156bb 2172 }
rahul_dahiya 0:fb8047b156bb 2173
rahul_dahiya 0:fb8047b156bb 2174 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2175 mbedtls_printf( "passed\n" );
rahul_dahiya 0:fb8047b156bb 2176
rahul_dahiya 0:fb8047b156bb 2177 cleanup:
rahul_dahiya 0:fb8047b156bb 2178
rahul_dahiya 0:fb8047b156bb 2179 if( ret < 0 && verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2180 mbedtls_printf( "Unexpected error, return code = %08X\n", ret );
rahul_dahiya 0:fb8047b156bb 2181
rahul_dahiya 0:fb8047b156bb 2182 mbedtls_ecp_group_free( &grp );
rahul_dahiya 0:fb8047b156bb 2183 mbedtls_ecp_point_free( &R );
rahul_dahiya 0:fb8047b156bb 2184 mbedtls_ecp_point_free( &P );
rahul_dahiya 0:fb8047b156bb 2185 mbedtls_mpi_free( &m );
rahul_dahiya 0:fb8047b156bb 2186
rahul_dahiya 0:fb8047b156bb 2187 if( verbose != 0 )
rahul_dahiya 0:fb8047b156bb 2188 mbedtls_printf( "\n" );
rahul_dahiya 0:fb8047b156bb 2189
rahul_dahiya 0:fb8047b156bb 2190 return( ret );
rahul_dahiya 0:fb8047b156bb 2191 }
rahul_dahiya 0:fb8047b156bb 2192
rahul_dahiya 0:fb8047b156bb 2193 #endif /* MBEDTLS_SELF_TEST */
rahul_dahiya 0:fb8047b156bb 2194
rahul_dahiya 0:fb8047b156bb 2195 #endif /* !MBEDTLS_ECP_ALT */
rahul_dahiya 0:fb8047b156bb 2196
rahul_dahiya 0:fb8047b156bb 2197 #endif /* MBEDTLS_ECP_C */