| 1 | /** |
| 2 | * \file aes.h |
| 3 | * |
| 4 | * \brief This file contains AES definitions and functions. |
| 5 | * |
| 6 | * The Advanced Encryption Standard (AES) specifies a FIPS-approved |
| 7 | * cryptographic algorithm that can be used to protect electronic |
| 8 | * data. |
| 9 | * |
| 10 | * The AES algorithm is a symmetric block cipher that can |
| 11 | * encrypt and decrypt information. For more information, see |
| 12 | * <em>FIPS Publication 197: Advanced Encryption Standard</em> and |
| 13 | * <em>ISO/IEC 18033-2:2006: Information technology -- Security |
| 14 | * techniques -- Encryption algorithms -- Part 2: Asymmetric |
| 15 | * ciphers</em>. |
| 16 | * |
| 17 | * The AES-XTS block mode is standardized by NIST SP 800-38E |
| 18 | * <https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-38e.pdf> |
| 19 | * and described in detail by IEEE P1619 |
| 20 | * <https://ieeexplore.ieee.org/servlet/opac?punumber=4375278>. |
| 21 | */ |
| 22 | |
| 23 | /* Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved. |
| 24 | * SPDX-License-Identifier: GPL-2.0 |
| 25 | * |
| 26 | * This program is free software; you can redistribute it and/or modify |
| 27 | * it under the terms of the GNU General Public License as published by |
| 28 | * the Free Software Foundation; either version 2 of the License, or |
| 29 | * (at your option) any later version. |
| 30 | * |
| 31 | * This program is distributed in the hope that it will be useful, |
| 32 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 33 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 34 | * GNU General Public License for more details. |
| 35 | * |
| 36 | * You should have received a copy of the GNU General Public License along |
| 37 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 38 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 39 | * |
| 40 | * This file is part of Mbed TLS (https://tls.mbed.org) |
| 41 | */ |
| 42 | |
| 43 | #ifndef MBEDTLS_AES_H |
| 44 | #define MBEDTLS_AES_H |
| 45 | |
| 46 | #if !defined(MBEDTLS_CONFIG_FILE) |
| 47 | #include "config.h" |
| 48 | #else |
| 49 | #include MBEDTLS_CONFIG_FILE |
| 50 | #endif |
| 51 | |
| 52 | #include <stddef.h> |
| 53 | #include <stdint.h> |
| 54 | |
| 55 | /* padlock.c and aesni.c rely on these values! */ |
| 56 | #define MBEDTLS_AES_ENCRYPT 1 /**< AES encryption. */ |
| 57 | #define MBEDTLS_AES_DECRYPT 0 /**< AES decryption. */ |
| 58 | |
| 59 | /* Error codes in range 0x0020-0x0022 */ |
| 60 | #define MBEDTLS_ERR_AES_INVALID_KEY_LENGTH -0x0020 /**< Invalid key length. */ |
| 61 | #define MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH -0x0022 /**< Invalid data input length. */ |
| 62 | |
| 63 | /* Error codes in range 0x0021-0x0025 */ |
| 64 | #define MBEDTLS_ERR_AES_BAD_INPUT_DATA -0x0021 /**< Invalid input data. */ |
| 65 | #define MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE -0x0023 /**< Feature not available. For example, an unsupported AES key size. */ |
| 66 | #define MBEDTLS_ERR_AES_HW_ACCEL_FAILED -0x0025 /**< AES hardware accelerator failed. */ |
| 67 | |
| 68 | #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \ |
| 69 | !defined(inline) && !defined(__cplusplus) |
| 70 | #define inline __inline |
| 71 | #endif |
| 72 | |
| 73 | #ifdef __cplusplus |
| 74 | extern "C" { |
| 75 | #endif |
| 76 | |
| 77 | #if !defined(MBEDTLS_AES_ALT) |
| 78 | // Regular implementation |
| 79 | // |
| 80 | |
| 81 | /** |
| 82 | * \brief The AES context-type definition. |
| 83 | */ |
| 84 | typedef struct mbedtls_aes_context |
| 85 | { |
| 86 | int nr; /*!< The number of rounds. */ |
| 87 | uint32_t *rk; /*!< AES round keys. */ |
| 88 | uint32_t buf[68]; /*!< Unaligned data buffer. This buffer can |
| 89 | hold 32 extra Bytes, which can be used for |
| 90 | one of the following purposes: |
| 91 | <ul><li>Alignment if VIA padlock is |
| 92 | used.</li> |
| 93 | <li>Simplifying key expansion in the 256-bit |
| 94 | case by generating an extra round key. |
| 95 | </li></ul> */ |
| 96 | } |
| 97 | mbedtls_aes_context; |
| 98 | |
| 99 | #if defined(MBEDTLS_CIPHER_MODE_XTS) |
| 100 | /** |
| 101 | * \brief The AES XTS context-type definition. |
| 102 | */ |
| 103 | typedef struct mbedtls_aes_xts_context |
| 104 | { |
| 105 | mbedtls_aes_context crypt; /*!< The AES context to use for AES block |
| 106 | encryption or decryption. */ |
| 107 | mbedtls_aes_context tweak; /*!< The AES context used for tweak |
| 108 | computation. */ |
| 109 | } mbedtls_aes_xts_context; |
| 110 | #endif /* MBEDTLS_CIPHER_MODE_XTS */ |
| 111 | |
| 112 | #else /* MBEDTLS_AES_ALT */ |
| 113 | #include "aes_alt.h" |
| 114 | #endif /* MBEDTLS_AES_ALT */ |
| 115 | |
| 116 | /** |
| 117 | * \brief This function initializes the specified AES context. |
| 118 | * |
| 119 | * It must be the first API called before using |
| 120 | * the context. |
| 121 | * |
| 122 | * \param ctx The AES context to initialize. |
| 123 | */ |
| 124 | void mbedtls_aes_init( mbedtls_aes_context *ctx ); |
| 125 | |
| 126 | /** |
| 127 | * \brief This function releases and clears the specified AES context. |
| 128 | * |
| 129 | * \param ctx The AES context to clear. |
| 130 | */ |
| 131 | void mbedtls_aes_free( mbedtls_aes_context *ctx ); |
| 132 | |
| 133 | #if defined(MBEDTLS_CIPHER_MODE_XTS) |
| 134 | /** |
| 135 | * \brief This function initializes the specified AES XTS context. |
| 136 | * |
| 137 | * It must be the first API called before using |
| 138 | * the context. |
| 139 | * |
| 140 | * \param ctx The AES XTS context to initialize. |
| 141 | */ |
| 142 | void mbedtls_aes_xts_init( mbedtls_aes_xts_context *ctx ); |
| 143 | |
| 144 | /** |
| 145 | * \brief This function releases and clears the specified AES XTS context. |
| 146 | * |
| 147 | * \param ctx The AES XTS context to clear. |
| 148 | */ |
| 149 | void mbedtls_aes_xts_free( mbedtls_aes_xts_context *ctx ); |
| 150 | #endif /* MBEDTLS_CIPHER_MODE_XTS */ |
| 151 | |
| 152 | /** |
| 153 | * \brief This function sets the encryption key. |
| 154 | * |
| 155 | * \param ctx The AES context to which the key should be bound. |
| 156 | * \param key The encryption key. |
| 157 | * \param keybits The size of data passed in bits. Valid options are: |
| 158 | * <ul><li>128 bits</li> |
| 159 | * <li>192 bits</li> |
| 160 | * <li>256 bits</li></ul> |
| 161 | * |
| 162 | * \return \c 0 on success. |
| 163 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. |
| 164 | */ |
| 165 | int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key, |
| 166 | unsigned int keybits ); |
| 167 | |
| 168 | /** |
| 169 | * \brief This function sets the decryption key. |
| 170 | * |
| 171 | * \param ctx The AES context to which the key should be bound. |
| 172 | * \param key The decryption key. |
| 173 | * \param keybits The size of data passed. Valid options are: |
| 174 | * <ul><li>128 bits</li> |
| 175 | * <li>192 bits</li> |
| 176 | * <li>256 bits</li></ul> |
| 177 | * |
| 178 | * \return \c 0 on success. |
| 179 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. |
| 180 | */ |
| 181 | int mbedtls_aes_setkey_dec( mbedtls_aes_context *ctx, const unsigned char *key, |
| 182 | unsigned int keybits ); |
| 183 | |
| 184 | #if defined(MBEDTLS_CIPHER_MODE_XTS) |
| 185 | /** |
| 186 | * \brief This function prepares an XTS context for encryption and |
| 187 | * sets the encryption key. |
| 188 | * |
| 189 | * \param ctx The AES XTS context to which the key should be bound. |
| 190 | * \param key The encryption key. This is comprised of the XTS key1 |
| 191 | * concatenated with the XTS key2. |
| 192 | * \param keybits The size of \p key passed in bits. Valid options are: |
| 193 | * <ul><li>256 bits (each of key1 and key2 is a 128-bit key)</li> |
| 194 | * <li>512 bits (each of key1 and key2 is a 256-bit key)</li></ul> |
| 195 | * |
| 196 | * \return \c 0 on success. |
| 197 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. |
| 198 | */ |
| 199 | int mbedtls_aes_xts_setkey_enc( mbedtls_aes_xts_context *ctx, |
| 200 | const unsigned char *key, |
| 201 | unsigned int keybits ); |
| 202 | |
| 203 | /** |
| 204 | * \brief This function prepares an XTS context for decryption and |
| 205 | * sets the decryption key. |
| 206 | * |
| 207 | * \param ctx The AES XTS context to which the key should be bound. |
| 208 | * \param key The decryption key. This is comprised of the XTS key1 |
| 209 | * concatenated with the XTS key2. |
| 210 | * \param keybits The size of \p key passed in bits. Valid options are: |
| 211 | * <ul><li>256 bits (each of key1 and key2 is a 128-bit key)</li> |
| 212 | * <li>512 bits (each of key1 and key2 is a 256-bit key)</li></ul> |
| 213 | * |
| 214 | * \return \c 0 on success. |
| 215 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. |
| 216 | */ |
| 217 | int mbedtls_aes_xts_setkey_dec( mbedtls_aes_xts_context *ctx, |
| 218 | const unsigned char *key, |
| 219 | unsigned int keybits ); |
| 220 | #endif /* MBEDTLS_CIPHER_MODE_XTS */ |
| 221 | |
| 222 | /** |
| 223 | * \brief This function performs an AES single-block encryption or |
| 224 | * decryption operation. |
| 225 | * |
| 226 | * It performs the operation defined in the \p mode parameter |
| 227 | * (encrypt or decrypt), on the input data buffer defined in |
| 228 | * the \p input parameter. |
| 229 | * |
| 230 | * mbedtls_aes_init(), and either mbedtls_aes_setkey_enc() or |
| 231 | * mbedtls_aes_setkey_dec() must be called before the first |
| 232 | * call to this API with the same context. |
| 233 | * |
| 234 | * \param ctx The AES context to use for encryption or decryption. |
| 235 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or |
| 236 | * #MBEDTLS_AES_DECRYPT. |
| 237 | * \param input The 16-Byte buffer holding the input data. |
| 238 | * \param output The 16-Byte buffer holding the output data. |
| 239 | |
| 240 | * \return \c 0 on success. |
| 241 | */ |
| 242 | int mbedtls_aes_crypt_ecb( mbedtls_aes_context *ctx, |
| 243 | int mode, |
| 244 | const unsigned char input[16], |
| 245 | unsigned char output[16] ); |
| 246 | |
| 247 | #if defined(MBEDTLS_CIPHER_MODE_CBC) |
| 248 | /** |
| 249 | * \brief This function performs an AES-CBC encryption or decryption operation |
| 250 | * on full blocks. |
| 251 | * |
| 252 | * It performs the operation defined in the \p mode |
| 253 | * parameter (encrypt/decrypt), on the input data buffer defined in |
| 254 | * the \p input parameter. |
| 255 | * |
| 256 | * It can be called as many times as needed, until all the input |
| 257 | * data is processed. mbedtls_aes_init(), and either |
| 258 | * mbedtls_aes_setkey_enc() or mbedtls_aes_setkey_dec() must be called |
| 259 | * before the first call to this API with the same context. |
| 260 | * |
| 261 | * \note This function operates on aligned blocks, that is, the input size |
| 262 | * must be a multiple of the AES block size of 16 Bytes. |
| 263 | * |
| 264 | * \note Upon exit, the content of the IV is updated so that you can |
| 265 | * call the same function again on the next |
| 266 | * block(s) of data and get the same result as if it was |
| 267 | * encrypted in one call. This allows a "streaming" usage. |
| 268 | * If you need to retain the contents of the IV, you should |
| 269 | * either save it manually or use the cipher module instead. |
| 270 | * |
| 271 | * |
| 272 | * \param ctx The AES context to use for encryption or decryption. |
| 273 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or |
| 274 | * #MBEDTLS_AES_DECRYPT. |
| 275 | * \param length The length of the input data in Bytes. This must be a |
| 276 | * multiple of the block size (16 Bytes). |
| 277 | * \param iv Initialization vector (updated after use). |
| 278 | * \param input The buffer holding the input data. |
| 279 | * \param output The buffer holding the output data. |
| 280 | * |
| 281 | * \return \c 0 on success. |
| 282 | * \return #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH |
| 283 | * on failure. |
| 284 | */ |
| 285 | int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx, |
| 286 | int mode, |
| 287 | size_t length, |
| 288 | unsigned char iv[16], |
| 289 | const unsigned char *input, |
| 290 | unsigned char *output ); |
| 291 | #endif /* MBEDTLS_CIPHER_MODE_CBC */ |
| 292 | |
| 293 | #if defined(MBEDTLS_CIPHER_MODE_XTS) |
| 294 | /** |
| 295 | * \brief This function performs an AES-XTS encryption or decryption |
| 296 | * operation for an entire XTS data unit. |
| 297 | * |
| 298 | * AES-XTS encrypts or decrypts blocks based on their location as |
| 299 | * defined by a data unit number. The data unit number must be |
| 300 | * provided by \p data_unit. |
| 301 | * |
| 302 | * NIST SP 800-38E limits the maximum size of a data unit to 2^20 |
| 303 | * AES blocks. If the data unit is larger than this, this function |
| 304 | * returns #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH. |
| 305 | * |
| 306 | * \param ctx The AES XTS context to use for AES XTS operations. |
| 307 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or |
| 308 | * #MBEDTLS_AES_DECRYPT. |
| 309 | * \param length The length of a data unit in bytes. This can be any |
| 310 | * length between 16 bytes and 2^24 bytes inclusive |
| 311 | * (between 1 and 2^20 block cipher blocks). |
| 312 | * \param data_unit The address of the data unit encoded as an array of 16 |
| 313 | * bytes in little-endian format. For disk encryption, this |
| 314 | * is typically the index of the block device sector that |
| 315 | * contains the data. |
| 316 | * \param input The buffer holding the input data (which is an entire |
| 317 | * data unit). This function reads \p length bytes from \p |
| 318 | * input. |
| 319 | * \param output The buffer holding the output data (which is an entire |
| 320 | * data unit). This function writes \p length bytes to \p |
| 321 | * output. |
| 322 | * |
| 323 | * \return \c 0 on success. |
| 324 | * \return #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH if \p length is |
| 325 | * smaller than an AES block in size (16 bytes) or if \p |
| 326 | * length is larger than 2^20 blocks (16 MiB). |
| 327 | */ |
| 328 | int mbedtls_aes_crypt_xts( mbedtls_aes_xts_context *ctx, |
| 329 | int mode, |
| 330 | size_t length, |
| 331 | const unsigned char data_unit[16], |
| 332 | const unsigned char *input, |
| 333 | unsigned char *output ); |
| 334 | #endif /* MBEDTLS_CIPHER_MODE_XTS */ |
| 335 | |
| 336 | #if defined(MBEDTLS_CIPHER_MODE_CFB) |
| 337 | /** |
| 338 | * \brief This function performs an AES-CFB128 encryption or decryption |
| 339 | * operation. |
| 340 | * |
| 341 | * It performs the operation defined in the \p mode |
| 342 | * parameter (encrypt or decrypt), on the input data buffer |
| 343 | * defined in the \p input parameter. |
| 344 | * |
| 345 | * For CFB, you must set up the context with mbedtls_aes_setkey_enc(), |
| 346 | * regardless of whether you are performing an encryption or decryption |
| 347 | * operation, that is, regardless of the \p mode parameter. This is |
| 348 | * because CFB mode uses the same key schedule for encryption and |
| 349 | * decryption. |
| 350 | * |
| 351 | * \note Upon exit, the content of the IV is updated so that you can |
| 352 | * call the same function again on the next |
| 353 | * block(s) of data and get the same result as if it was |
| 354 | * encrypted in one call. This allows a "streaming" usage. |
| 355 | * If you need to retain the contents of the |
| 356 | * IV, you must either save it manually or use the cipher |
| 357 | * module instead. |
| 358 | * |
| 359 | * |
| 360 | * \param ctx The AES context to use for encryption or decryption. |
| 361 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or |
| 362 | * #MBEDTLS_AES_DECRYPT. |
| 363 | * \param length The length of the input data. |
| 364 | * \param iv_off The offset in IV (updated after use). |
| 365 | * \param iv The initialization vector (updated after use). |
| 366 | * \param input The buffer holding the input data. |
| 367 | * \param output The buffer holding the output data. |
| 368 | * |
| 369 | * \return \c 0 on success. |
| 370 | */ |
| 371 | int mbedtls_aes_crypt_cfb128( mbedtls_aes_context *ctx, |
| 372 | int mode, |
| 373 | size_t length, |
| 374 | size_t *iv_off, |
| 375 | unsigned char iv[16], |
| 376 | const unsigned char *input, |
| 377 | unsigned char *output ); |
| 378 | |
| 379 | /** |
| 380 | * \brief This function performs an AES-CFB8 encryption or decryption |
| 381 | * operation. |
| 382 | * |
| 383 | * It performs the operation defined in the \p mode |
| 384 | * parameter (encrypt/decrypt), on the input data buffer defined |
| 385 | * in the \p input parameter. |
| 386 | * |
| 387 | * Due to the nature of CFB, you must use the same key schedule for |
| 388 | * both encryption and decryption operations. Therefore, you must |
| 389 | * use the context initialized with mbedtls_aes_setkey_enc() for |
| 390 | * both #MBEDTLS_AES_ENCRYPT and #MBEDTLS_AES_DECRYPT. |
| 391 | * |
| 392 | * \note Upon exit, the content of the IV is updated so that you can |
| 393 | * call the same function again on the next |
| 394 | * block(s) of data and get the same result as if it was |
| 395 | * encrypted in one call. This allows a "streaming" usage. |
| 396 | * If you need to retain the contents of the |
| 397 | * IV, you should either save it manually or use the cipher |
| 398 | * module instead. |
| 399 | * |
| 400 | * |
| 401 | * \param ctx The AES context to use for encryption or decryption. |
| 402 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or |
| 403 | * #MBEDTLS_AES_DECRYPT |
| 404 | * \param length The length of the input data. |
| 405 | * \param iv The initialization vector (updated after use). |
| 406 | * \param input The buffer holding the input data. |
| 407 | * \param output The buffer holding the output data. |
| 408 | * |
| 409 | * \return \c 0 on success. |
| 410 | */ |
| 411 | int mbedtls_aes_crypt_cfb8( mbedtls_aes_context *ctx, |
| 412 | int mode, |
| 413 | size_t length, |
| 414 | unsigned char iv[16], |
| 415 | const unsigned char *input, |
| 416 | unsigned char *output ); |
| 417 | #endif /*MBEDTLS_CIPHER_MODE_CFB */ |
| 418 | |
| 419 | #if defined(MBEDTLS_CIPHER_MODE_OFB) |
| 420 | /** |
| 421 | * \brief This function performs an AES-OFB (Output Feedback Mode) |
| 422 | * encryption or decryption operation. |
| 423 | * |
| 424 | * For OFB, you must set up the context with |
| 425 | * mbedtls_aes_setkey_enc(), regardless of whether you are |
| 426 | * performing an encryption or decryption operation. This is |
| 427 | * because OFB mode uses the same key schedule for encryption and |
| 428 | * decryption. |
| 429 | * |
| 430 | * The OFB operation is identical for encryption or decryption, |
| 431 | * therefore no operation mode needs to be specified. |
| 432 | * |
| 433 | * \note Upon exit, the content of iv, the Initialisation Vector, is |
| 434 | * updated so that you can call the same function again on the next |
| 435 | * block(s) of data and get the same result as if it was encrypted |
| 436 | * in one call. This allows a "streaming" usage, by initialising |
| 437 | * iv_off to 0 before the first call, and preserving its value |
| 438 | * between calls. |
| 439 | * |
| 440 | * For non-streaming use, the iv should be initialised on each call |
| 441 | * to a unique value, and iv_off set to 0 on each call. |
| 442 | * |
| 443 | * If you need to retain the contents of the initialisation vector, |
| 444 | * you must either save it manually or use the cipher module |
| 445 | * instead. |
| 446 | * |
| 447 | * \warning For the OFB mode, the initialisation vector must be unique |
| 448 | * every encryption operation. Reuse of an initialisation vector |
| 449 | * will compromise security. |
| 450 | * |
| 451 | * \param ctx The AES context to use for encryption or decryption. |
| 452 | * \param length The length of the input data. |
| 453 | * \param iv_off The offset in IV (updated after use). |
| 454 | * \param iv The initialization vector (updated after use). |
| 455 | * \param input The buffer holding the input data. |
| 456 | * \param output The buffer holding the output data. |
| 457 | * |
| 458 | * \return \c 0 on success. |
| 459 | */ |
| 460 | int mbedtls_aes_crypt_ofb( mbedtls_aes_context *ctx, |
| 461 | size_t length, |
| 462 | size_t *iv_off, |
| 463 | unsigned char iv[16], |
| 464 | const unsigned char *input, |
| 465 | unsigned char *output ); |
| 466 | |
| 467 | #endif /* MBEDTLS_CIPHER_MODE_OFB */ |
| 468 | |
| 469 | #if defined(MBEDTLS_CIPHER_MODE_CTR) |
| 470 | /** |
| 471 | * \brief This function performs an AES-CTR encryption or decryption |
| 472 | * operation. |
| 473 | * |
| 474 | * This function performs the operation defined in the \p mode |
| 475 | * parameter (encrypt/decrypt), on the input data buffer |
| 476 | * defined in the \p input parameter. |
| 477 | * |
| 478 | * Due to the nature of CTR, you must use the same key schedule |
| 479 | * for both encryption and decryption operations. Therefore, you |
| 480 | * must use the context initialized with mbedtls_aes_setkey_enc() |
| 481 | * for both #MBEDTLS_AES_ENCRYPT and #MBEDTLS_AES_DECRYPT. |
| 482 | * |
| 483 | * \warning You must never reuse a nonce value with the same key. Doing so |
| 484 | * would void the encryption for the two messages encrypted with |
| 485 | * the same nonce and key. |
| 486 | * |
| 487 | * There are two common strategies for managing nonces with CTR: |
| 488 | * |
| 489 | * 1. You can handle everything as a single message processed over |
| 490 | * successive calls to this function. In that case, you want to |
| 491 | * set \p nonce_counter and \p nc_off to 0 for the first call, and |
| 492 | * then preserve the values of \p nonce_counter, \p nc_off and \p |
| 493 | * stream_block across calls to this function as they will be |
| 494 | * updated by this function. |
| 495 | * |
| 496 | * With this strategy, you must not encrypt more than 2**128 |
| 497 | * blocks of data with the same key. |
| 498 | * |
| 499 | * 2. You can encrypt separate messages by dividing the \p |
| 500 | * nonce_counter buffer in two areas: the first one used for a |
| 501 | * per-message nonce, handled by yourself, and the second one |
| 502 | * updated by this function internally. |
| 503 | * |
| 504 | * For example, you might reserve the first 12 bytes for the |
| 505 | * per-message nonce, and the last 4 bytes for internal use. In that |
| 506 | * case, before calling this function on a new message you need to |
| 507 | * set the first 12 bytes of \p nonce_counter to your chosen nonce |
| 508 | * value, the last 4 to 0, and \p nc_off to 0 (which will cause \p |
| 509 | * stream_block to be ignored). That way, you can encrypt at most |
| 510 | * 2**96 messages of up to 2**32 blocks each with the same key. |
| 511 | * |
| 512 | * The per-message nonce (or information sufficient to reconstruct |
| 513 | * it) needs to be communicated with the ciphertext and must be unique. |
| 514 | * The recommended way to ensure uniqueness is to use a message |
| 515 | * counter. An alternative is to generate random nonces, but this |
| 516 | * limits the number of messages that can be securely encrypted: |
| 517 | * for example, with 96-bit random nonces, you should not encrypt |
| 518 | * more than 2**32 messages with the same key. |
| 519 | * |
| 520 | * Note that for both stategies, sizes are measured in blocks and |
| 521 | * that an AES block is 16 bytes. |
| 522 | * |
| 523 | * \warning Upon return, \p stream_block contains sensitive data. Its |
| 524 | * content must not be written to insecure storage and should be |
| 525 | * securely discarded as soon as it's no longer needed. |
| 526 | * |
| 527 | * \param ctx The AES context to use for encryption or decryption. |
| 528 | * \param length The length of the input data. |
| 529 | * \param nc_off The offset in the current \p stream_block, for |
| 530 | * resuming within the current cipher stream. The |
| 531 | * offset pointer should be 0 at the start of a stream. |
| 532 | * \param nonce_counter The 128-bit nonce and counter. |
| 533 | * \param stream_block The saved stream block for resuming. This is |
| 534 | * overwritten by the function. |
| 535 | * \param input The buffer holding the input data. |
| 536 | * \param output The buffer holding the output data. |
| 537 | * |
| 538 | * \return \c 0 on success. |
| 539 | */ |
| 540 | int mbedtls_aes_crypt_ctr( mbedtls_aes_context *ctx, |
| 541 | size_t length, |
| 542 | size_t *nc_off, |
| 543 | unsigned char nonce_counter[16], |
| 544 | unsigned char stream_block[16], |
| 545 | const unsigned char *input, |
| 546 | unsigned char *output ); |
| 547 | #endif /* MBEDTLS_CIPHER_MODE_CTR */ |
| 548 | |
| 549 | /** |
| 550 | * \brief Internal AES block encryption function. This is only |
| 551 | * exposed to allow overriding it using |
| 552 | * \c MBEDTLS_AES_ENCRYPT_ALT. |
| 553 | * |
| 554 | * \param ctx The AES context to use for encryption. |
| 555 | * \param input The plaintext block. |
| 556 | * \param output The output (ciphertext) block. |
| 557 | * |
| 558 | * \return \c 0 on success. |
| 559 | */ |
| 560 | int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx, |
| 561 | const unsigned char input[16], |
| 562 | unsigned char output[16] ); |
| 563 | |
| 564 | /** |
| 565 | * \brief Internal AES block decryption function. This is only |
| 566 | * exposed to allow overriding it using see |
| 567 | * \c MBEDTLS_AES_DECRYPT_ALT. |
| 568 | * |
| 569 | * \param ctx The AES context to use for decryption. |
| 570 | * \param input The ciphertext block. |
| 571 | * \param output The output (plaintext) block. |
| 572 | * |
| 573 | * \return \c 0 on success. |
| 574 | */ |
| 575 | int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx, |
| 576 | const unsigned char input[16], |
| 577 | unsigned char output[16] ); |
| 578 | |
| 579 | #if !defined(MBEDTLS_DEPRECATED_REMOVED) |
| 580 | #if defined(MBEDTLS_DEPRECATED_WARNING) |
| 581 | #define MBEDTLS_DEPRECATED __attribute__((deprecated)) |
| 582 | #else |
| 583 | #define MBEDTLS_DEPRECATED |
| 584 | #endif |
| 585 | /** |
| 586 | * \brief Deprecated internal AES block encryption function |
| 587 | * without return value. |
| 588 | * |
| 589 | * \deprecated Superseded by mbedtls_aes_encrypt_ext() in 2.5.0. |
| 590 | * |
| 591 | * \param ctx The AES context to use for encryption. |
| 592 | * \param input Plaintext block. |
| 593 | * \param output Output (ciphertext) block. |
| 594 | */ |
| 595 | MBEDTLS_DEPRECATED void mbedtls_aes_encrypt( mbedtls_aes_context *ctx, |
| 596 | const unsigned char input[16], |
| 597 | unsigned char output[16] ); |
| 598 | |
| 599 | /** |
| 600 | * \brief Deprecated internal AES block decryption function |
| 601 | * without return value. |
| 602 | * |
| 603 | * \deprecated Superseded by mbedtls_aes_decrypt_ext() in 2.5.0. |
| 604 | * |
| 605 | * \param ctx The AES context to use for decryption. |
| 606 | * \param input Ciphertext block. |
| 607 | * \param output Output (plaintext) block. |
| 608 | */ |
| 609 | MBEDTLS_DEPRECATED void mbedtls_aes_decrypt( mbedtls_aes_context *ctx, |
| 610 | const unsigned char input[16], |
| 611 | unsigned char output[16] ); |
| 612 | |
| 613 | #undef MBEDTLS_DEPRECATED |
| 614 | #endif /* !MBEDTLS_DEPRECATED_REMOVED */ |
| 615 | |
| 616 | /** |
| 617 | * \brief Checkup routine. |
| 618 | * |
| 619 | * \return \c 0 on success. |
| 620 | * \return \c 1 on failure. |
| 621 | */ |
| 622 | int mbedtls_aes_self_test( int verbose ); |
| 623 | |
| 624 | #ifdef __cplusplus |
| 625 | } |
| 626 | #endif |
| 627 | |
| 628 | #endif /* aes.h */ |