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Dependents: TYBLE16_simple_data_logger TYBLE16_MP3_Air
havege.c
00001 /** 00002 * \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion 00003 * 00004 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 00005 * SPDX-License-Identifier: Apache-2.0 00006 * 00007 * Licensed under the Apache License, Version 2.0 (the "License"); you may 00008 * not use this file except in compliance with the License. 00009 * You may obtain a copy of the License at 00010 * 00011 * http://www.apache.org/licenses/LICENSE-2.0 00012 * 00013 * Unless required by applicable law or agreed to in writing, software 00014 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 00015 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00016 * See the License for the specific language governing permissions and 00017 * limitations under the License. 00018 * 00019 * This file is part of mbed TLS (https://tls.mbed.org) 00020 */ 00021 /* 00022 * The HAVEGE RNG was designed by Andre Seznec in 2002. 00023 * 00024 * http://www.irisa.fr/caps/projects/hipsor/publi.php 00025 * 00026 * Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr 00027 */ 00028 00029 #if !defined(MBEDTLS_CONFIG_FILE) 00030 #include "mbedtls/config.h" 00031 #else 00032 #include MBEDTLS_CONFIG_FILE 00033 #endif 00034 00035 #if defined(MBEDTLS_HAVEGE_C) 00036 00037 #include "mbedtls/havege.h" 00038 #include "mbedtls/timing.h" 00039 #include "mbedtls/platform_util.h" 00040 00041 #include <stdint.h> 00042 #include <string.h> 00043 00044 /* ------------------------------------------------------------------------ 00045 * On average, one iteration accesses two 8-word blocks in the havege WALK 00046 * table, and generates 16 words in the RES array. 00047 * 00048 * The data read in the WALK table is updated and permuted after each use. 00049 * The result of the hardware clock counter read is used for this update. 00050 * 00051 * 25 conditional tests are present. The conditional tests are grouped in 00052 * two nested groups of 12 conditional tests and 1 test that controls the 00053 * permutation; on average, there should be 6 tests executed and 3 of them 00054 * should be mispredicted. 00055 * ------------------------------------------------------------------------ 00056 */ 00057 00058 #define SWAP(X,Y) { uint32_t *T = (X); (X) = (Y); (Y) = T; } 00059 00060 #define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1; 00061 #define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1; 00062 00063 #define TST1_LEAVE U1++; } 00064 #define TST2_LEAVE U2++; } 00065 00066 #define ONE_ITERATION \ 00067 \ 00068 PTEST = PT1 >> 20; \ 00069 \ 00070 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ 00071 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ 00072 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ 00073 \ 00074 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ 00075 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ 00076 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ 00077 \ 00078 PTX = (PT1 >> 18) & 7; \ 00079 PT1 &= 0x1FFF; \ 00080 PT2 &= 0x1FFF; \ 00081 CLK = (uint32_t) mbedtls_timing_hardclock(); \ 00082 \ 00083 i = 0; \ 00084 A = &WALK[PT1 ]; RES[i++] ^= *A; \ 00085 B = &WALK[PT2 ]; RES[i++] ^= *B; \ 00086 C = &WALK[PT1 ^ 1]; RES[i++] ^= *C; \ 00087 D = &WALK[PT2 ^ 4]; RES[i++] ^= *D; \ 00088 \ 00089 IN = (*A >> (1)) ^ (*A << (31)) ^ CLK; \ 00090 *A = (*B >> (2)) ^ (*B << (30)) ^ CLK; \ 00091 *B = IN ^ U1; \ 00092 *C = (*C >> (3)) ^ (*C << (29)) ^ CLK; \ 00093 *D = (*D >> (4)) ^ (*D << (28)) ^ CLK; \ 00094 \ 00095 A = &WALK[PT1 ^ 2]; RES[i++] ^= *A; \ 00096 B = &WALK[PT2 ^ 2]; RES[i++] ^= *B; \ 00097 C = &WALK[PT1 ^ 3]; RES[i++] ^= *C; \ 00098 D = &WALK[PT2 ^ 6]; RES[i++] ^= *D; \ 00099 \ 00100 if( PTEST & 1 ) SWAP( A, C ); \ 00101 \ 00102 IN = (*A >> (5)) ^ (*A << (27)) ^ CLK; \ 00103 *A = (*B >> (6)) ^ (*B << (26)) ^ CLK; \ 00104 *B = IN; CLK = (uint32_t) mbedtls_timing_hardclock(); \ 00105 *C = (*C >> (7)) ^ (*C << (25)) ^ CLK; \ 00106 *D = (*D >> (8)) ^ (*D << (24)) ^ CLK; \ 00107 \ 00108 A = &WALK[PT1 ^ 4]; \ 00109 B = &WALK[PT2 ^ 1]; \ 00110 \ 00111 PTEST = PT2 >> 1; \ 00112 \ 00113 PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]); \ 00114 PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8); \ 00115 PTY = (PT2 >> 10) & 7; \ 00116 \ 00117 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ 00118 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ 00119 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ 00120 \ 00121 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ 00122 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ 00123 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ 00124 \ 00125 C = &WALK[PT1 ^ 5]; \ 00126 D = &WALK[PT2 ^ 5]; \ 00127 \ 00128 RES[i++] ^= *A; \ 00129 RES[i++] ^= *B; \ 00130 RES[i++] ^= *C; \ 00131 RES[i++] ^= *D; \ 00132 \ 00133 IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK; \ 00134 *A = (*B >> (10)) ^ (*B << (22)) ^ CLK; \ 00135 *B = IN ^ U2; \ 00136 *C = (*C >> (11)) ^ (*C << (21)) ^ CLK; \ 00137 *D = (*D >> (12)) ^ (*D << (20)) ^ CLK; \ 00138 \ 00139 A = &WALK[PT1 ^ 6]; RES[i++] ^= *A; \ 00140 B = &WALK[PT2 ^ 3]; RES[i++] ^= *B; \ 00141 C = &WALK[PT1 ^ 7]; RES[i++] ^= *C; \ 00142 D = &WALK[PT2 ^ 7]; RES[i++] ^= *D; \ 00143 \ 00144 IN = (*A >> (13)) ^ (*A << (19)) ^ CLK; \ 00145 *A = (*B >> (14)) ^ (*B << (18)) ^ CLK; \ 00146 *B = IN; \ 00147 *C = (*C >> (15)) ^ (*C << (17)) ^ CLK; \ 00148 *D = (*D >> (16)) ^ (*D << (16)) ^ CLK; \ 00149 \ 00150 PT1 = ( RES[( i - 8 ) ^ PTX] ^ \ 00151 WALK[PT1 ^ PTX ^ 7] ) & (~1); \ 00152 PT1 ^= (PT2 ^ 0x10) & 0x10; \ 00153 \ 00154 for( n++, i = 0; i < 16; i++ ) \ 00155 hs->pool[n % MBEDTLS_HAVEGE_COLLECT_SIZE] ^= RES[i]; 00156 00157 /* 00158 * Entropy gathering function 00159 */ 00160 static void havege_fill( mbedtls_havege_state *hs ) 00161 { 00162 size_t n = 0; 00163 size_t i; 00164 uint32_t U1, U2, *A, *B, *C, *D; 00165 uint32_t PT1, PT2, *WALK, RES[16]; 00166 uint32_t PTX, PTY, CLK, PTEST, IN; 00167 00168 WALK = hs->WALK; 00169 PT1 = hs->PT1; 00170 PT2 = hs->PT2; 00171 00172 PTX = U1 = 0; 00173 PTY = U2 = 0; 00174 00175 (void)PTX; 00176 00177 memset( RES, 0, sizeof( RES ) ); 00178 00179 while( n < MBEDTLS_HAVEGE_COLLECT_SIZE * 4 ) 00180 { 00181 ONE_ITERATION 00182 ONE_ITERATION 00183 ONE_ITERATION 00184 ONE_ITERATION 00185 } 00186 00187 hs->PT1 = PT1; 00188 hs->PT2 = PT2; 00189 00190 hs->offset[0] = 0; 00191 hs->offset[1] = MBEDTLS_HAVEGE_COLLECT_SIZE / 2; 00192 } 00193 00194 /* 00195 * HAVEGE initialization 00196 */ 00197 void mbedtls_havege_init( mbedtls_havege_state *hs ) 00198 { 00199 memset( hs, 0, sizeof( mbedtls_havege_state ) ); 00200 00201 havege_fill( hs ); 00202 } 00203 00204 void mbedtls_havege_free( mbedtls_havege_state *hs ) 00205 { 00206 if( hs == NULL ) 00207 return; 00208 00209 mbedtls_platform_zeroize( hs, sizeof( mbedtls_havege_state ) ); 00210 } 00211 00212 /* 00213 * HAVEGE rand function 00214 */ 00215 int mbedtls_havege_random( void *p_rng, unsigned char *buf, size_t len ) 00216 { 00217 uint32_t val; 00218 size_t use_len; 00219 mbedtls_havege_state *hs = (mbedtls_havege_state *) p_rng; 00220 unsigned char *p = buf; 00221 00222 while( len > 0 ) 00223 { 00224 use_len = len; 00225 if( use_len > sizeof( val ) ) 00226 use_len = sizeof( val ); 00227 00228 if( hs->offset[1] >= MBEDTLS_HAVEGE_COLLECT_SIZE ) 00229 havege_fill( hs ); 00230 00231 val = hs->pool[hs->offset[0]++]; 00232 val ^= hs->pool[hs->offset[1]++]; 00233 00234 memcpy( p, &val, use_len ); 00235 00236 len -= use_len; 00237 p += use_len; 00238 } 00239 00240 return( 0 ); 00241 } 00242 00243 #endif /* MBEDTLS_HAVEGE_C */
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