cipher.h

00001 /**
00002  * \file cipher.h
00003  *
00004  * \brief Generic cipher wrapper.
00005  *
00006  * \author Adriaan de Jong <dejong@fox-it.com>
00007  *
00008  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
00009  *  SPDX-License-Identifier: Apache-2.0
00010  *
00011  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00012  *  not use this file except in compliance with the License.
00013  *  You may obtain a copy of the License at
00014  *
00015  *  http://www.apache.org/licenses/LICENSE-2.0
00016  *
00017  *  Unless required by applicable law or agreed to in writing, software
00018  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00019  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00020  *  See the License for the specific language governing permissions and
00021  *  limitations under the License.
00022  *
00023  *  This file is part of mbed TLS (https://tls.mbed.org)
00024  */
00025 
00026 #ifndef MBEDTLS_CIPHER_H
00027 #define MBEDTLS_CIPHER_H
00028 
00029 #if !defined(MBEDTLS_CONFIG_FILE)
00030 #include "config.h"
00031 #else
00032 #include MBEDTLS_CONFIG_FILE
00033 #endif
00034 
00035 #include <stddef.h>
00036 
00037 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CCM_C)
00038 #define MBEDTLS_CIPHER_MODE_AEAD
00039 #endif
00040 
00041 #if defined(MBEDTLS_CIPHER_MODE_CBC)
00042 #define MBEDTLS_CIPHER_MODE_WITH_PADDING
00043 #endif
00044 
00045 #if defined(MBEDTLS_ARC4_C)
00046 #define MBEDTLS_CIPHER_MODE_STREAM
00047 #endif
00048 
00049 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
00050     !defined(inline) && !defined(__cplusplus)
00051 #define inline __inline
00052 #endif
00053 
00054 #define MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE            -0x6080  /**< The selected feature is not available. */
00055 #define MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA                 -0x6100  /**< Bad input parameters to function. */
00056 #define MBEDTLS_ERR_CIPHER_ALLOC_FAILED                   -0x6180  /**< Failed to allocate memory. */
00057 #define MBEDTLS_ERR_CIPHER_INVALID_PADDING                -0x6200  /**< Input data contains invalid padding and is rejected. */
00058 #define MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED            -0x6280  /**< Decryption of block requires a full block. */
00059 #define MBEDTLS_ERR_CIPHER_AUTH_FAILED                    -0x6300  /**< Authentication failed (for AEAD modes). */
00060 
00061 #define MBEDTLS_CIPHER_VARIABLE_IV_LEN     0x01    /**< Cipher accepts IVs of variable length */
00062 #define MBEDTLS_CIPHER_VARIABLE_KEY_LEN    0x02    /**< Cipher accepts keys of variable length */
00063 
00064 #ifdef __cplusplus
00065 extern "C" {
00066 #endif
00067 
00068 typedef enum {
00069     MBEDTLS_CIPHER_ID_NONE = 0,
00070     MBEDTLS_CIPHER_ID_NULL,
00071     MBEDTLS_CIPHER_ID_AES,
00072     MBEDTLS_CIPHER_ID_DES,
00073     MBEDTLS_CIPHER_ID_3DES,
00074     MBEDTLS_CIPHER_ID_CAMELLIA,
00075     MBEDTLS_CIPHER_ID_BLOWFISH,
00076     MBEDTLS_CIPHER_ID_ARC4,
00077 } mbedtls_cipher_id_t;
00078 
00079 typedef enum {
00080     MBEDTLS_CIPHER_NONE = 0,
00081     MBEDTLS_CIPHER_NULL,
00082     MBEDTLS_CIPHER_AES_128_ECB,
00083     MBEDTLS_CIPHER_AES_192_ECB,
00084     MBEDTLS_CIPHER_AES_256_ECB,
00085     MBEDTLS_CIPHER_AES_128_CBC,
00086     MBEDTLS_CIPHER_AES_192_CBC,
00087     MBEDTLS_CIPHER_AES_256_CBC,
00088     MBEDTLS_CIPHER_AES_128_CFB128,
00089     MBEDTLS_CIPHER_AES_192_CFB128,
00090     MBEDTLS_CIPHER_AES_256_CFB128,
00091     MBEDTLS_CIPHER_AES_128_CTR,
00092     MBEDTLS_CIPHER_AES_192_CTR,
00093     MBEDTLS_CIPHER_AES_256_CTR,
00094     MBEDTLS_CIPHER_AES_128_GCM,
00095     MBEDTLS_CIPHER_AES_192_GCM,
00096     MBEDTLS_CIPHER_AES_256_GCM,
00097     MBEDTLS_CIPHER_CAMELLIA_128_ECB,
00098     MBEDTLS_CIPHER_CAMELLIA_192_ECB,
00099     MBEDTLS_CIPHER_CAMELLIA_256_ECB,
00100     MBEDTLS_CIPHER_CAMELLIA_128_CBC,
00101     MBEDTLS_CIPHER_CAMELLIA_192_CBC,
00102     MBEDTLS_CIPHER_CAMELLIA_256_CBC,
00103     MBEDTLS_CIPHER_CAMELLIA_128_CFB128,
00104     MBEDTLS_CIPHER_CAMELLIA_192_CFB128,
00105     MBEDTLS_CIPHER_CAMELLIA_256_CFB128,
00106     MBEDTLS_CIPHER_CAMELLIA_128_CTR,
00107     MBEDTLS_CIPHER_CAMELLIA_192_CTR,
00108     MBEDTLS_CIPHER_CAMELLIA_256_CTR,
00109     MBEDTLS_CIPHER_CAMELLIA_128_GCM,
00110     MBEDTLS_CIPHER_CAMELLIA_192_GCM,
00111     MBEDTLS_CIPHER_CAMELLIA_256_GCM,
00112     MBEDTLS_CIPHER_DES_ECB,
00113     MBEDTLS_CIPHER_DES_CBC,
00114     MBEDTLS_CIPHER_DES_EDE_ECB,
00115     MBEDTLS_CIPHER_DES_EDE_CBC,
00116     MBEDTLS_CIPHER_DES_EDE3_ECB,
00117     MBEDTLS_CIPHER_DES_EDE3_CBC,
00118     MBEDTLS_CIPHER_BLOWFISH_ECB,
00119     MBEDTLS_CIPHER_BLOWFISH_CBC,
00120     MBEDTLS_CIPHER_BLOWFISH_CFB64,
00121     MBEDTLS_CIPHER_BLOWFISH_CTR,
00122     MBEDTLS_CIPHER_ARC4_128,
00123     MBEDTLS_CIPHER_AES_128_CCM,
00124     MBEDTLS_CIPHER_AES_192_CCM,
00125     MBEDTLS_CIPHER_AES_256_CCM,
00126     MBEDTLS_CIPHER_CAMELLIA_128_CCM,
00127     MBEDTLS_CIPHER_CAMELLIA_192_CCM,
00128     MBEDTLS_CIPHER_CAMELLIA_256_CCM,
00129 } mbedtls_cipher_type_t;
00130 
00131 typedef enum {
00132     MBEDTLS_MODE_NONE = 0,
00133     MBEDTLS_MODE_ECB,
00134     MBEDTLS_MODE_CBC,
00135     MBEDTLS_MODE_CFB,
00136     MBEDTLS_MODE_OFB, /* Unused! */
00137     MBEDTLS_MODE_CTR,
00138     MBEDTLS_MODE_GCM,
00139     MBEDTLS_MODE_STREAM,
00140     MBEDTLS_MODE_CCM,
00141 } mbedtls_cipher_mode_t;
00142 
00143 typedef enum {
00144     MBEDTLS_PADDING_PKCS7 = 0,     /**< PKCS7 padding (default)        */
00145     MBEDTLS_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding         */
00146     MBEDTLS_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding             */
00147     MBEDTLS_PADDING_ZEROS,         /**< zero padding (not reversible!) */
00148     MBEDTLS_PADDING_NONE,          /**< never pad (full blocks only)   */
00149 } mbedtls_cipher_padding_t ;
00150 
00151 typedef enum {
00152     MBEDTLS_OPERATION_NONE = -1,
00153     MBEDTLS_DECRYPT = 0,
00154     MBEDTLS_ENCRYPT,
00155 } mbedtls_operation_t;
00156 
00157 enum {
00158     /** Undefined key length */
00159     MBEDTLS_KEY_LENGTH_NONE = 0,
00160     /** Key length, in bits (including parity), for DES keys */
00161     MBEDTLS_KEY_LENGTH_DES  = 64,
00162     /** Key length, in bits (including parity), for DES in two key EDE */
00163     MBEDTLS_KEY_LENGTH_DES_EDE = 128,
00164     /** Key length, in bits (including parity), for DES in three-key EDE */
00165     MBEDTLS_KEY_LENGTH_DES_EDE3 = 192,
00166 };
00167 
00168 /** Maximum length of any IV, in bytes */
00169 #define MBEDTLS_MAX_IV_LENGTH      16
00170 /** Maximum block size of any cipher, in bytes */
00171 #define MBEDTLS_MAX_BLOCK_LENGTH   16
00172 
00173 /**
00174  * Base cipher information (opaque struct).
00175  */
00176 typedef struct mbedtls_cipher_base_t mbedtls_cipher_base_t;
00177 
00178 /**
00179  * Cipher information. Allows cipher functions to be called in a generic way.
00180  */
00181 typedef struct {
00182     /** Full cipher identifier (e.g. MBEDTLS_CIPHER_AES_256_CBC) */
00183     mbedtls_cipher_type_t type;
00184 
00185     /** Cipher mode (e.g. MBEDTLS_MODE_CBC) */
00186     mbedtls_cipher_mode_t mode;
00187 
00188     /** Cipher key length, in bits (default length for variable sized ciphers)
00189      *  (Includes parity bits for ciphers like DES) */
00190     unsigned int key_bitlen;
00191 
00192     /** Name of the cipher */
00193     const char * name;
00194 
00195     /** IV/NONCE size, in bytes.
00196      *  For cipher that accept many sizes: recommended size */
00197     unsigned int iv_size;
00198 
00199     /** Flags for variable IV size, variable key size, etc. */
00200     int flags;
00201 
00202     /** block size, in bytes */
00203     unsigned int block_size;
00204 
00205     /** Base cipher information and functions */
00206     const mbedtls_cipher_base_t *base;
00207 
00208 } mbedtls_cipher_info_t;
00209 
00210 /**
00211  * Generic cipher context.
00212  */
00213 typedef struct {
00214     /** Information about the associated cipher */
00215     const mbedtls_cipher_info_t *cipher_info;
00216 
00217     /** Key length to use */
00218     int key_bitlen;
00219 
00220     /** Operation that the context's key has been initialised for */
00221     mbedtls_operation_t operation;
00222 
00223 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
00224     /** Padding functions to use, if relevant for cipher mode */
00225     void (*add_padding)( unsigned char *output, size_t olen, size_t data_len );
00226     int (*get_padding)( unsigned char *input, size_t ilen, size_t *data_len );
00227 #endif
00228 
00229     /** Buffer for data that hasn't been encrypted yet */
00230     unsigned char unprocessed_data[MBEDTLS_MAX_BLOCK_LENGTH];
00231 
00232     /** Number of bytes that still need processing */
00233     size_t unprocessed_len;
00234 
00235     /** Current IV or NONCE_COUNTER for CTR-mode */
00236     unsigned char iv[MBEDTLS_MAX_IV_LENGTH];
00237 
00238     /** IV size in bytes (for ciphers with variable-length IVs) */
00239     size_t iv_size;
00240 
00241     /** Cipher-specific context */
00242     void *cipher_ctx;
00243 } mbedtls_cipher_context_t;
00244 
00245 /**
00246  * \brief Returns the list of ciphers supported by the generic cipher module.
00247  *
00248  * \return              a statically allocated array of ciphers, the last entry
00249  *                      is 0.
00250  */
00251 const int *mbedtls_cipher_list( void );
00252 
00253 /**
00254  * \brief               Returns the cipher information structure associated
00255  *                      with the given cipher name.
00256  *
00257  * \param cipher_name   Name of the cipher to search for.
00258  *
00259  * \return              the cipher information structure associated with the
00260  *                      given cipher_name, or NULL if not found.
00261  */
00262 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name );
00263 
00264 /**
00265  * \brief               Returns the cipher information structure associated
00266  *                      with the given cipher type.
00267  *
00268  * \param cipher_type   Type of the cipher to search for.
00269  *
00270  * \return              the cipher information structure associated with the
00271  *                      given cipher_type, or NULL if not found.
00272  */
00273 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type );
00274 
00275 /**
00276  * \brief               Returns the cipher information structure associated
00277  *                      with the given cipher id, key size and mode.
00278  *
00279  * \param cipher_id     Id of the cipher to search for
00280  *                      (e.g. MBEDTLS_CIPHER_ID_AES)
00281  * \param key_bitlen    Length of the key in bits
00282  * \param mode          Cipher mode (e.g. MBEDTLS_MODE_CBC)
00283  *
00284  * \return              the cipher information structure associated with the
00285  *                      given cipher_type, or NULL if not found.
00286  */
00287 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id,
00288                                               int key_bitlen,
00289                                               const mbedtls_cipher_mode_t mode );
00290 
00291 /**
00292  * \brief               Initialize a cipher_context (as NONE)
00293  */
00294 void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx );
00295 
00296 /**
00297  * \brief               Free and clear the cipher-specific context of ctx.
00298  *                      Freeing ctx itself remains the responsibility of the
00299  *                      caller.
00300  */
00301 void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx );
00302 
00303 /**
00304  * \brief               Initialises and fills the cipher context structure with
00305  *                      the appropriate values.
00306  *
00307  * \note                Currently also clears structure. In future versions you
00308  *                      will be required to call mbedtls_cipher_init() on the structure
00309  *                      first.
00310  *
00311  * \param ctx           context to initialise. May not be NULL.
00312  * \param cipher_info   cipher to use.
00313  *
00314  * \return              0 on success,
00315  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter failure,
00316  *                      MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the
00317  *                      cipher-specific context failed.
00318  */
00319 int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info );
00320 
00321 /**
00322  * \brief               Returns the block size of the given cipher.
00323  *
00324  * \param ctx           cipher's context. Must have been initialised.
00325  *
00326  * \return              size of the cipher's blocks, or 0 if ctx has not been
00327  *                      initialised.
00328  */
00329 static inline unsigned int mbedtls_cipher_get_block_size( const mbedtls_cipher_context_t *ctx )
00330 {
00331     if( NULL == ctx || NULL == ctx->cipher_info )
00332         return 0;
00333 
00334     return ctx->cipher_info->block_size;
00335 }
00336 
00337 /**
00338  * \brief               Returns the mode of operation for the cipher.
00339  *                      (e.g. MBEDTLS_MODE_CBC)
00340  *
00341  * \param ctx           cipher's context. Must have been initialised.
00342  *
00343  * \return              mode of operation, or MBEDTLS_MODE_NONE if ctx
00344  *                      has not been initialised.
00345  */
00346 static inline mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode( const mbedtls_cipher_context_t *ctx )
00347 {
00348     if( NULL == ctx || NULL == ctx->cipher_info )
00349         return MBEDTLS_MODE_NONE;
00350 
00351     return ctx->cipher_info->mode;
00352 }
00353 
00354 /**
00355  * \brief               Returns the size of the cipher's IV/NONCE in bytes.
00356  *
00357  * \param ctx           cipher's context. Must have been initialised.
00358  *
00359  * \return              If IV has not been set yet: (recommended) IV size
00360  *                      (0 for ciphers not using IV/NONCE).
00361  *                      If IV has already been set: actual size.
00362  */
00363 static inline int mbedtls_cipher_get_iv_size( const mbedtls_cipher_context_t *ctx )
00364 {
00365     if( NULL == ctx || NULL == ctx->cipher_info )
00366         return 0;
00367 
00368     if( ctx->iv_size != 0 )
00369         return (int) ctx->iv_size;
00370 
00371     return (int) ctx->cipher_info->iv_size;
00372 }
00373 
00374 /**
00375  * \brief               Returns the type of the given cipher.
00376  *
00377  * \param ctx           cipher's context. Must have been initialised.
00378  *
00379  * \return              type of the cipher, or MBEDTLS_CIPHER_NONE if ctx has
00380  *                      not been initialised.
00381  */
00382 static inline mbedtls_cipher_type_t mbedtls_cipher_get_type( const mbedtls_cipher_context_t *ctx )
00383 {
00384     if( NULL == ctx || NULL == ctx->cipher_info )
00385         return MBEDTLS_CIPHER_NONE;
00386 
00387     return ctx->cipher_info->type;
00388 }
00389 
00390 /**
00391  * \brief               Returns the name of the given cipher, as a string.
00392  *
00393  * \param ctx           cipher's context. Must have been initialised.
00394  *
00395  * \return              name of the cipher, or NULL if ctx was not initialised.
00396  */
00397 static inline const char *mbedtls_cipher_get_name( const mbedtls_cipher_context_t *ctx )
00398 {
00399     if( NULL == ctx || NULL == ctx->cipher_info )
00400         return 0;
00401 
00402     return ctx->cipher_info->name;
00403 }
00404 
00405 /**
00406  * \brief               Returns the key length of the cipher.
00407  *
00408  * \param ctx           cipher's context. Must have been initialised.
00409  *
00410  * \return              cipher's key length, in bits, or
00411  *                      MBEDTLS_KEY_LENGTH_NONE if ctx has not been
00412  *                      initialised.
00413  */
00414 static inline int mbedtls_cipher_get_key_bitlen( const mbedtls_cipher_context_t *ctx )
00415 {
00416     if( NULL == ctx || NULL == ctx->cipher_info )
00417         return MBEDTLS_KEY_LENGTH_NONE;
00418 
00419     return (int) ctx->cipher_info->key_bitlen;
00420 }
00421 
00422 /**
00423  * \brief               Returns the operation of the given cipher.
00424  *
00425  * \param ctx           cipher's context. Must have been initialised.
00426  *
00427  * \return              operation (MBEDTLS_ENCRYPT or MBEDTLS_DECRYPT),
00428  *                      or MBEDTLS_OPERATION_NONE if ctx has not been
00429  *                      initialised.
00430  */
00431 static inline mbedtls_operation_t mbedtls_cipher_get_operation( const mbedtls_cipher_context_t *ctx )
00432 {
00433     if( NULL == ctx || NULL == ctx->cipher_info )
00434         return MBEDTLS_OPERATION_NONE;
00435 
00436     return ctx->operation;
00437 }
00438 
00439 /**
00440  * \brief               Set the key to use with the given context.
00441  *
00442  * \param ctx           generic cipher context. May not be NULL. Must have been
00443  *                      initialised using cipher_context_from_type or
00444  *                      cipher_context_from_string.
00445  * \param key           The key to use.
00446  * \param key_bitlen    key length to use, in bits.
00447  * \param operation     Operation that the key will be used for, either
00448  *                      MBEDTLS_ENCRYPT or MBEDTLS_DECRYPT.
00449  *
00450  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
00451  *                      parameter verification fails or a cipher specific
00452  *                      error code.
00453  */
00454 int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key,
00455                    int key_bitlen, const mbedtls_operation_t operation );
00456 
00457 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
00458 /**
00459  * \brief               Set padding mode, for cipher modes that use padding.
00460  *                      (Default: PKCS7 padding.)
00461  *
00462  * \param ctx           generic cipher context
00463  * \param mode          padding mode
00464  *
00465  * \returns             0 on success, MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE
00466  *                      if selected padding mode is not supported, or
00467  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode
00468  *                      does not support padding.
00469  */
00470 int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t  mode );
00471 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
00472 
00473 /**
00474  * \brief               Set the initialization vector (IV) or nonce
00475  *
00476  * \param ctx           generic cipher context
00477  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00478  * \param iv_len        IV length for ciphers with variable-size IV;
00479  *                      discarded by ciphers with fixed-size IV.
00480  *
00481  * \returns             0 on success, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
00482  *
00483  * \note                Some ciphers don't use IVs nor NONCE. For these
00484  *                      ciphers, this function has no effect.
00485  */
00486 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
00487                    const unsigned char *iv, size_t iv_len );
00488 
00489 /**
00490  * \brief               Finish preparation of the given context
00491  *
00492  * \param ctx           generic cipher context
00493  *
00494  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
00495  *                      if parameter verification fails.
00496  */
00497 int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx );
00498 
00499 #if defined(MBEDTLS_GCM_C)
00500 /**
00501  * \brief               Add additional data (for AEAD ciphers).
00502  *                      Currently only supported with GCM.
00503  *                      Must be called exactly once, after mbedtls_cipher_reset().
00504  *
00505  * \param ctx           generic cipher context
00506  * \param ad            Additional data to use.
00507  * \param ad_len        Length of ad.
00508  *
00509  * \return              0 on success, or a specific error code.
00510  */
00511 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
00512                       const unsigned char *ad, size_t ad_len );
00513 #endif /* MBEDTLS_GCM_C */
00514 
00515 /**
00516  * \brief               Generic cipher update function. Encrypts/decrypts
00517  *                      using the given cipher context. Writes as many block
00518  *                      size'd blocks of data as possible to output. Any data
00519  *                      that cannot be written immediately will either be added
00520  *                      to the next block, or flushed when cipher_final is
00521  *                      called.
00522  *                      Exception: for MBEDTLS_MODE_ECB, expects single block
00523  *                                 in size (e.g. 16 bytes for AES)
00524  *
00525  * \param ctx           generic cipher context
00526  * \param input         buffer holding the input data
00527  * \param ilen          length of the input data
00528  * \param output        buffer for the output data. Should be able to hold at
00529  *                      least ilen + block_size. Cannot be the same buffer as
00530  *                      input!
00531  * \param olen          length of the output data, will be filled with the
00532  *                      actual number of bytes written.
00533  *
00534  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
00535  *                      parameter verification fails,
00536  *                      MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE on an
00537  *                      unsupported mode for a cipher or a cipher specific
00538  *                      error code.
00539  *
00540  * \note                If the underlying cipher is GCM, all calls to this
00541  *                      function, except the last one before mbedtls_cipher_finish(),
00542  *                      must have ilen a multiple of the block size.
00543  */
00544 int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input,
00545                    size_t ilen, unsigned char *output, size_t *olen );
00546 
00547 /**
00548  * \brief               Generic cipher finalisation function. If data still
00549  *                      needs to be flushed from an incomplete block, data
00550  *                      contained within it will be padded with the size of
00551  *                      the last block, and written to the output buffer.
00552  *
00553  * \param ctx           Generic cipher context
00554  * \param output        buffer to write data to. Needs block_size available.
00555  * \param olen          length of the data written to the output buffer.
00556  *
00557  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
00558  *                      parameter verification fails,
00559  *                      MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption
00560  *                      expected a full block but was not provided one,
00561  *                      MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
00562  *                      while decrypting or a cipher specific error code.
00563  */
00564 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
00565                    unsigned char *output, size_t *olen );
00566 
00567 #if defined(MBEDTLS_GCM_C)
00568 /**
00569  * \brief               Write tag for AEAD ciphers.
00570  *                      Currently only supported with GCM.
00571  *                      Must be called after mbedtls_cipher_finish().
00572  *
00573  * \param ctx           Generic cipher context
00574  * \param tag           buffer to write the tag
00575  * \param tag_len       Length of the tag to write
00576  *
00577  * \return              0 on success, or a specific error code.
00578  */
00579 int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
00580                       unsigned char *tag, size_t tag_len );
00581 
00582 /**
00583  * \brief               Check tag for AEAD ciphers.
00584  *                      Currently only supported with GCM.
00585  *                      Must be called after mbedtls_cipher_finish().
00586  *
00587  * \param ctx           Generic cipher context
00588  * \param tag           Buffer holding the tag
00589  * \param tag_len       Length of the tag to check
00590  *
00591  * \return              0 on success, or a specific error code.
00592  */
00593 int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
00594                       const unsigned char *tag, size_t tag_len );
00595 #endif /* MBEDTLS_GCM_C */
00596 
00597 /**
00598  * \brief               Generic all-in-one encryption/decryption
00599  *                      (for all ciphers except AEAD constructs).
00600  *
00601  * \param ctx           generic cipher context
00602  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00603  * \param iv_len        IV length for ciphers with variable-size IV;
00604  *                      discarded by ciphers with fixed-size IV.
00605  * \param input         buffer holding the input data
00606  * \param ilen          length of the input data
00607  * \param output        buffer for the output data. Should be able to hold at
00608  *                      least ilen + block_size. Cannot be the same buffer as
00609  *                      input!
00610  * \param olen          length of the output data, will be filled with the
00611  *                      actual number of bytes written.
00612  *
00613  * \note                Some ciphers don't use IVs nor NONCE. For these
00614  *                      ciphers, use iv = NULL and iv_len = 0.
00615  *
00616  * \returns             0 on success, or
00617  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
00618  *                      MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption
00619  *                      expected a full block but was not provided one, or
00620  *                      MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
00621  *                      while decrypting, or
00622  *                      a cipher specific error code.
00623  */
00624 int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx,
00625                   const unsigned char *iv, size_t iv_len,
00626                   const unsigned char *input, size_t ilen,
00627                   unsigned char *output, size_t *olen );
00628 
00629 #if defined(MBEDTLS_CIPHER_MODE_AEAD)
00630 /**
00631  * \brief               Generic autenticated encryption (AEAD ciphers).
00632  *
00633  * \param ctx           generic cipher context
00634  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00635  * \param iv_len        IV length for ciphers with variable-size IV;
00636  *                      discarded by ciphers with fixed-size IV.
00637  * \param ad            Additional data to authenticate.
00638  * \param ad_len        Length of ad.
00639  * \param input         buffer holding the input data
00640  * \param ilen          length of the input data
00641  * \param output        buffer for the output data.
00642  *                      Should be able to hold at least ilen.
00643  * \param olen          length of the output data, will be filled with the
00644  *                      actual number of bytes written.
00645  * \param tag           buffer for the authentication tag
00646  * \param tag_len       desired tag length
00647  *
00648  * \returns             0 on success, or
00649  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
00650  *                      a cipher specific error code.
00651  */
00652 int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx,
00653                          const unsigned char *iv, size_t iv_len,
00654                          const unsigned char *ad, size_t ad_len,
00655                          const unsigned char *input, size_t ilen,
00656                          unsigned char *output, size_t *olen,
00657                          unsigned char *tag, size_t tag_len );
00658 
00659 /**
00660  * \brief               Generic autenticated decryption (AEAD ciphers).
00661  *
00662  * \param ctx           generic cipher context
00663  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00664  * \param iv_len        IV length for ciphers with variable-size IV;
00665  *                      discarded by ciphers with fixed-size IV.
00666  * \param ad            Additional data to be authenticated.
00667  * \param ad_len        Length of ad.
00668  * \param input         buffer holding the input data
00669  * \param ilen          length of the input data
00670  * \param output        buffer for the output data.
00671  *                      Should be able to hold at least ilen.
00672  * \param olen          length of the output data, will be filled with the
00673  *                      actual number of bytes written.
00674  * \param tag           buffer holding the authentication tag
00675  * \param tag_len       length of the authentication tag
00676  *
00677  * \returns             0 on success, or
00678  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
00679  *                      MBEDTLS_ERR_CIPHER_AUTH_FAILED if data isn't authentic,
00680  *                      or a cipher specific error code.
00681  *
00682  * \note                If the data is not authentic, then the output buffer
00683  *                      is zeroed out to prevent the unauthentic plaintext to
00684  *                      be used by mistake, making this interface safer.
00685  */
00686 int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
00687                          const unsigned char *iv, size_t iv_len,
00688                          const unsigned char *ad, size_t ad_len,
00689                          const unsigned char *input, size_t ilen,
00690                          unsigned char *output, size_t *olen,
00691                          const unsigned char *tag, size_t tag_len );
00692 #endif /* MBEDTLS_CIPHER_MODE_AEAD */
00693 
00694 #ifdef __cplusplus
00695 }
00696 #endif
00697 
00698 #endif /* MBEDTLS_CIPHER_H */