Doug Anson / mbedTLSLibrary

mbed TLS library

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include/polarssl/ctr_drbg.h@0:137634ff4186, 2015-06-11 (annotated)

Committer:
ansond
Date:
Thu Jun 11 03:27:03 2015 +0000
Revision:
0:137634ff4186
initial commit

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ansond 0:137634ff4186 1 /**
ansond 0:137634ff4186 2 * \file ctr_drbg.h
ansond 0:137634ff4186 3 *
ansond 0:137634ff4186 4 * \brief CTR_DRBG based on AES-256 (NIST SP 800-90)
ansond 0:137634ff4186 5 *
ansond 0:137634ff4186 6 * Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
ansond 0:137634ff4186 7 *
ansond 0:137634ff4186 8 * This file is part of mbed TLS (https://tls.mbed.org)
ansond 0:137634ff4186 9 *
ansond 0:137634ff4186 10 * This program is free software; you can redistribute it and/or modify
ansond 0:137634ff4186 11 * it under the terms of the GNU General Public License as published by
ansond 0:137634ff4186 12 * the Free Software Foundation; either version 2 of the License, or
ansond 0:137634ff4186 13 * (at your option) any later version.
ansond 0:137634ff4186 14 *
ansond 0:137634ff4186 15 * This program is distributed in the hope that it will be useful,
ansond 0:137634ff4186 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
ansond 0:137634ff4186 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
ansond 0:137634ff4186 18 * GNU General Public License for more details.
ansond 0:137634ff4186 19 *
ansond 0:137634ff4186 20 * You should have received a copy of the GNU General Public License along
ansond 0:137634ff4186 21 * with this program; if not, write to the Free Software Foundation, Inc.,
ansond 0:137634ff4186 22 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
ansond 0:137634ff4186 23 */
ansond 0:137634ff4186 24 #ifndef POLARSSL_CTR_DRBG_H
ansond 0:137634ff4186 25 #define POLARSSL_CTR_DRBG_H
ansond 0:137634ff4186 26
ansond 0:137634ff4186 27 #include "aes.h"
ansond 0:137634ff4186 28
ansond 0:137634ff4186 29 #define POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED -0x0034 /**< The entropy source failed. */
ansond 0:137634ff4186 30 #define POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG -0x0036 /**< Too many random requested in single call. */
ansond 0:137634ff4186 31 #define POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG -0x0038 /**< Input too large (Entropy + additional). */
ansond 0:137634ff4186 32 #define POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR -0x003A /**< Read/write error in file. */
ansond 0:137634ff4186 33
ansond 0:137634ff4186 34 #define CTR_DRBG_BLOCKSIZE 16 /**< Block size used by the cipher */
ansond 0:137634ff4186 35 #define CTR_DRBG_KEYSIZE 32 /**< Key size used by the cipher */
ansond 0:137634ff4186 36 #define CTR_DRBG_KEYBITS ( CTR_DRBG_KEYSIZE * 8 )
ansond 0:137634ff4186 37 #define CTR_DRBG_SEEDLEN ( CTR_DRBG_KEYSIZE + CTR_DRBG_BLOCKSIZE )
ansond 0:137634ff4186 38 /**< The seed length (counter + AES key) */
ansond 0:137634ff4186 39
ansond 0:137634ff4186 40 /**
ansond 0:137634ff4186 41 * \name SECTION: Module settings
ansond 0:137634ff4186 42 *
ansond 0:137634ff4186 43 * The configuration options you can set for this module are in this section.
ansond 0:137634ff4186 44 * Either change them in config.h or define them on the compiler command line.
ansond 0:137634ff4186 45 * \{
ansond 0:137634ff4186 46 */
ansond 0:137634ff4186 47
ansond 0:137634ff4186 48 #if !defined(CTR_DRBG_ENTROPY_LEN)
ansond 0:137634ff4186 49 #if defined(POLARSSL_SHA512_C) && !defined(POLARSSL_ENTROPY_FORCE_SHA256)
ansond 0:137634ff4186 50 #define CTR_DRBG_ENTROPY_LEN 48 /**< Amount of entropy used per seed by default (48 with SHA-512, 32 with SHA-256) */
ansond 0:137634ff4186 51 #else
ansond 0:137634ff4186 52 #define CTR_DRBG_ENTROPY_LEN 32 /**< Amount of entropy used per seed by default (48 with SHA-512, 32 with SHA-256) */
ansond 0:137634ff4186 53 #endif
ansond 0:137634ff4186 54 #endif
ansond 0:137634ff4186 55
ansond 0:137634ff4186 56 #if !defined(CTR_DRBG_RESEED_INTERVAL)
ansond 0:137634ff4186 57 #define CTR_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */
ansond 0:137634ff4186 58 #endif
ansond 0:137634ff4186 59
ansond 0:137634ff4186 60 #if !defined(CTR_DRBG_MAX_INPUT)
ansond 0:137634ff4186 61 #define CTR_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */
ansond 0:137634ff4186 62 #endif
ansond 0:137634ff4186 63
ansond 0:137634ff4186 64 #if !defined(CTR_DRBG_MAX_REQUEST)
ansond 0:137634ff4186 65 #define CTR_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */
ansond 0:137634ff4186 66 #endif
ansond 0:137634ff4186 67
ansond 0:137634ff4186 68 #if !defined(CTR_DRBG_MAX_SEED_INPUT)
ansond 0:137634ff4186 69 #define CTR_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */
ansond 0:137634ff4186 70 #endif
ansond 0:137634ff4186 71
ansond 0:137634ff4186 72 /* \} name SECTION: Module settings */
ansond 0:137634ff4186 73
ansond 0:137634ff4186 74 #define CTR_DRBG_PR_OFF 0 /**< No prediction resistance */
ansond 0:137634ff4186 75 #define CTR_DRBG_PR_ON 1 /**< Prediction resistance enabled */
ansond 0:137634ff4186 76
ansond 0:137634ff4186 77 #ifdef __cplusplus
ansond 0:137634ff4186 78 extern "C" {
ansond 0:137634ff4186 79 #endif
ansond 0:137634ff4186 80
ansond 0:137634ff4186 81 /**
ansond 0:137634ff4186 82 * \brief CTR_DRBG context structure
ansond 0:137634ff4186 83 */
ansond 0:137634ff4186 84 typedef struct
ansond 0:137634ff4186 85 {
ansond 0:137634ff4186 86 unsigned char counter[16]; /*!< counter (V) */
ansond 0:137634ff4186 87 int reseed_counter; /*!< reseed counter */
ansond 0:137634ff4186 88 int prediction_resistance; /*!< enable prediction resistance (Automatic
ansond 0:137634ff4186 89 reseed before every random generation) */
ansond 0:137634ff4186 90 size_t entropy_len; /*!< amount of entropy grabbed on each
ansond 0:137634ff4186 91 (re)seed */
ansond 0:137634ff4186 92 int reseed_interval; /*!< reseed interval */
ansond 0:137634ff4186 93
ansond 0:137634ff4186 94 aes_context aes_ctx; /*!< AES context */
ansond 0:137634ff4186 95
ansond 0:137634ff4186 96 /*
ansond 0:137634ff4186 97 * Callbacks (Entropy)
ansond 0:137634ff4186 98 */
ansond 0:137634ff4186 99 int (*f_entropy)(void *, unsigned char *, size_t);
ansond 0:137634ff4186 100
ansond 0:137634ff4186 101 void *p_entropy; /*!< context for the entropy function */
ansond 0:137634ff4186 102 }
ansond 0:137634ff4186 103 ctr_drbg_context;
ansond 0:137634ff4186 104
ansond 0:137634ff4186 105 /**
ansond 0:137634ff4186 106 * \brief CTR_DRBG initialization
ansond 0:137634ff4186 107 *
ansond 0:137634ff4186 108 * Note: Personalization data can be provided in addition to the more generic
ansond 0:137634ff4186 109 * entropy source to make this instantiation as unique as possible.
ansond 0:137634ff4186 110 *
ansond 0:137634ff4186 111 * \param ctx CTR_DRBG context to be initialized
ansond 0:137634ff4186 112 * \param f_entropy Entropy callback (p_entropy, buffer to fill, buffer
ansond 0:137634ff4186 113 * length)
ansond 0:137634ff4186 114 * \param p_entropy Entropy context
ansond 0:137634ff4186 115 * \param custom Personalization data (Device specific identifiers)
ansond 0:137634ff4186 116 * (Can be NULL)
ansond 0:137634ff4186 117 * \param len Length of personalization data
ansond 0:137634ff4186 118 *
ansond 0:137634ff4186 119 * \return 0 if successful, or
ansond 0:137634ff4186 120 * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED
ansond 0:137634ff4186 121 */
ansond 0:137634ff4186 122 int ctr_drbg_init( ctr_drbg_context *ctx,
ansond 0:137634ff4186 123 int (*f_entropy)(void *, unsigned char *, size_t),
ansond 0:137634ff4186 124 void *p_entropy,
ansond 0:137634ff4186 125 const unsigned char *custom,
ansond 0:137634ff4186 126 size_t len );
ansond 0:137634ff4186 127
ansond 0:137634ff4186 128 /**
ansond 0:137634ff4186 129 * \brief Clear CTR_CRBG context data
ansond 0:137634ff4186 130 *
ansond 0:137634ff4186 131 * \param ctx CTR_DRBG context to clear
ansond 0:137634ff4186 132 */
ansond 0:137634ff4186 133 void ctr_drbg_free( ctr_drbg_context *ctx );
ansond 0:137634ff4186 134
ansond 0:137634ff4186 135 /**
ansond 0:137634ff4186 136 * \brief Enable / disable prediction resistance (Default: Off)
ansond 0:137634ff4186 137 *
ansond 0:137634ff4186 138 * Note: If enabled, entropy is used for ctx->entropy_len before each call!
ansond 0:137634ff4186 139 * Only use this if you have ample supply of good entropy!
ansond 0:137634ff4186 140 *
ansond 0:137634ff4186 141 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 142 * \param resistance CTR_DRBG_PR_ON or CTR_DRBG_PR_OFF
ansond 0:137634ff4186 143 */
ansond 0:137634ff4186 144 void ctr_drbg_set_prediction_resistance( ctr_drbg_context *ctx,
ansond 0:137634ff4186 145 int resistance );
ansond 0:137634ff4186 146
ansond 0:137634ff4186 147 /**
ansond 0:137634ff4186 148 * \brief Set the amount of entropy grabbed on each (re)seed
ansond 0:137634ff4186 149 * (Default: CTR_DRBG_ENTROPY_LEN)
ansond 0:137634ff4186 150 *
ansond 0:137634ff4186 151 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 152 * \param len Amount of entropy to grab
ansond 0:137634ff4186 153 */
ansond 0:137634ff4186 154 void ctr_drbg_set_entropy_len( ctr_drbg_context *ctx,
ansond 0:137634ff4186 155 size_t len );
ansond 0:137634ff4186 156
ansond 0:137634ff4186 157 /**
ansond 0:137634ff4186 158 * \brief Set the reseed interval
ansond 0:137634ff4186 159 * (Default: CTR_DRBG_RESEED_INTERVAL)
ansond 0:137634ff4186 160 *
ansond 0:137634ff4186 161 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 162 * \param interval Reseed interval
ansond 0:137634ff4186 163 */
ansond 0:137634ff4186 164 void ctr_drbg_set_reseed_interval( ctr_drbg_context *ctx,
ansond 0:137634ff4186 165 int interval );
ansond 0:137634ff4186 166
ansond 0:137634ff4186 167 /**
ansond 0:137634ff4186 168 * \brief CTR_DRBG reseeding (extracts data from entropy source)
ansond 0:137634ff4186 169 *
ansond 0:137634ff4186 170 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 171 * \param additional Additional data to add to state (Can be NULL)
ansond 0:137634ff4186 172 * \param len Length of additional data
ansond 0:137634ff4186 173 *
ansond 0:137634ff4186 174 * \return 0 if successful, or
ansond 0:137634ff4186 175 * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED
ansond 0:137634ff4186 176 */
ansond 0:137634ff4186 177 int ctr_drbg_reseed( ctr_drbg_context *ctx,
ansond 0:137634ff4186 178 const unsigned char *additional, size_t len );
ansond 0:137634ff4186 179
ansond 0:137634ff4186 180 /**
ansond 0:137634ff4186 181 * \brief CTR_DRBG update state
ansond 0:137634ff4186 182 *
ansond 0:137634ff4186 183 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 184 * \param additional Additional data to update state with
ansond 0:137634ff4186 185 * \param add_len Length of additional data
ansond 0:137634ff4186 186 *
ansond 0:137634ff4186 187 * \note If add_len is greater than CTR_DRBG_MAX_SEED_INPUT,
ansond 0:137634ff4186 188 * only the first CTR_DRBG_MAX_SEED_INPUT bytes are used,
ansond 0:137634ff4186 189 * the remaining ones are silently discarded.
ansond 0:137634ff4186 190 */
ansond 0:137634ff4186 191 void ctr_drbg_update( ctr_drbg_context *ctx,
ansond 0:137634ff4186 192 const unsigned char *additional, size_t add_len );
ansond 0:137634ff4186 193
ansond 0:137634ff4186 194 /**
ansond 0:137634ff4186 195 * \brief CTR_DRBG generate random with additional update input
ansond 0:137634ff4186 196 *
ansond 0:137634ff4186 197 * Note: Automatically reseeds if reseed_counter is reached.
ansond 0:137634ff4186 198 *
ansond 0:137634ff4186 199 * \param p_rng CTR_DRBG context
ansond 0:137634ff4186 200 * \param output Buffer to fill
ansond 0:137634ff4186 201 * \param output_len Length of the buffer
ansond 0:137634ff4186 202 * \param additional Additional data to update with (Can be NULL)
ansond 0:137634ff4186 203 * \param add_len Length of additional data
ansond 0:137634ff4186 204 *
ansond 0:137634ff4186 205 * \return 0 if successful, or
ansond 0:137634ff4186 206 * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED, or
ansond 0:137634ff4186 207 * POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG
ansond 0:137634ff4186 208 */
ansond 0:137634ff4186 209 int ctr_drbg_random_with_add( void *p_rng,
ansond 0:137634ff4186 210 unsigned char *output, size_t output_len,
ansond 0:137634ff4186 211 const unsigned char *additional, size_t add_len );
ansond 0:137634ff4186 212
ansond 0:137634ff4186 213 /**
ansond 0:137634ff4186 214 * \brief CTR_DRBG generate random
ansond 0:137634ff4186 215 *
ansond 0:137634ff4186 216 * Note: Automatically reseeds if reseed_counter is reached.
ansond 0:137634ff4186 217 *
ansond 0:137634ff4186 218 * \param p_rng CTR_DRBG context
ansond 0:137634ff4186 219 * \param output Buffer to fill
ansond 0:137634ff4186 220 * \param output_len Length of the buffer
ansond 0:137634ff4186 221 *
ansond 0:137634ff4186 222 * \return 0 if successful, or
ansond 0:137634ff4186 223 * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED, or
ansond 0:137634ff4186 224 * POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG
ansond 0:137634ff4186 225 */
ansond 0:137634ff4186 226 int ctr_drbg_random( void *p_rng,
ansond 0:137634ff4186 227 unsigned char *output, size_t output_len );
ansond 0:137634ff4186 228
ansond 0:137634ff4186 229 #if defined(POLARSSL_FS_IO)
ansond 0:137634ff4186 230 /**
ansond 0:137634ff4186 231 * \brief Write a seed file
ansond 0:137634ff4186 232 *
ansond 0:137634ff4186 233 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 234 * \param path Name of the file
ansond 0:137634ff4186 235 *
ansond 0:137634ff4186 236 * \return 0 if successful,
ansond 0:137634ff4186 237 * POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR on file error, or
ansond 0:137634ff4186 238 * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED
ansond 0:137634ff4186 239 */
ansond 0:137634ff4186 240 int ctr_drbg_write_seed_file( ctr_drbg_context *ctx, const char *path );
ansond 0:137634ff4186 241
ansond 0:137634ff4186 242 /**
ansond 0:137634ff4186 243 * \brief Read and update a seed file. Seed is added to this
ansond 0:137634ff4186 244 * instance
ansond 0:137634ff4186 245 *
ansond 0:137634ff4186 246 * \param ctx CTR_DRBG context
ansond 0:137634ff4186 247 * \param path Name of the file
ansond 0:137634ff4186 248 *
ansond 0:137634ff4186 249 * \return 0 if successful,
ansond 0:137634ff4186 250 * POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR on file error,
ansond 0:137634ff4186 251 * POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or
ansond 0:137634ff4186 252 * POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG
ansond 0:137634ff4186 253 */
ansond 0:137634ff4186 254 int ctr_drbg_update_seed_file( ctr_drbg_context *ctx, const char *path );
ansond 0:137634ff4186 255 #endif /* POLARSSL_FS_IO */
ansond 0:137634ff4186 256
ansond 0:137634ff4186 257 /**
ansond 0:137634ff4186 258 * \brief Checkup routine
ansond 0:137634ff4186 259 *
ansond 0:137634ff4186 260 * \return 0 if successful, or 1 if the test failed
ansond 0:137634ff4186 261 */
ansond 0:137634ff4186 262 int ctr_drbg_self_test( int verbose );
ansond 0:137634ff4186 263
ansond 0:137634ff4186 264 /* Internal functions (do not call directly) */
ansond 0:137634ff4186 265 int ctr_drbg_init_entropy_len( ctr_drbg_context *,
ansond 0:137634ff4186 266 int (*)(void *, unsigned char *, size_t), void *,
ansond 0:137634ff4186 267 const unsigned char *, size_t, size_t );
ansond 0:137634ff4186 268
ansond 0:137634ff4186 269 #ifdef __cplusplus
ansond 0:137634ff4186 270 }
ansond 0:137634ff4186 271 #endif
ansond 0:137634ff4186 272
ansond 0:137634ff4186 273 #endif /* ctr_drbg.h */
ansond 0:137634ff4186 274