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 #define MBEDTLS_ERR_CIPHER_INVALID_CONTEXT              -0x6380  /**< The context is invalid, eg because it was free()ed. */
00061 
00062 #define MBEDTLS_CIPHER_VARIABLE_IV_LEN     0x01    /**< Cipher accepts IVs of variable length */
00063 #define MBEDTLS_CIPHER_VARIABLE_KEY_LEN    0x02    /**< Cipher accepts keys of variable length */
00064 
00065 #ifdef __cplusplus
00066 extern "C" {
00067 #endif
00068 
00069 typedef enum {
00070     MBEDTLS_CIPHER_ID_NONE = 0,
00071     MBEDTLS_CIPHER_ID_NULL,
00072     MBEDTLS_CIPHER_ID_AES,
00073     MBEDTLS_CIPHER_ID_DES,
00074     MBEDTLS_CIPHER_ID_3DES,
00075     MBEDTLS_CIPHER_ID_CAMELLIA,
00076     MBEDTLS_CIPHER_ID_BLOWFISH,
00077     MBEDTLS_CIPHER_ID_ARC4,
00078 } mbedtls_cipher_id_t;
00079 
00080 typedef enum {
00081     MBEDTLS_CIPHER_NONE = 0,
00082     MBEDTLS_CIPHER_NULL,
00083     MBEDTLS_CIPHER_AES_128_ECB,
00084     MBEDTLS_CIPHER_AES_192_ECB,
00085     MBEDTLS_CIPHER_AES_256_ECB,
00086     MBEDTLS_CIPHER_AES_128_CBC,
00087     MBEDTLS_CIPHER_AES_192_CBC,
00088     MBEDTLS_CIPHER_AES_256_CBC,
00089     MBEDTLS_CIPHER_AES_128_CFB128,
00090     MBEDTLS_CIPHER_AES_192_CFB128,
00091     MBEDTLS_CIPHER_AES_256_CFB128,
00092     MBEDTLS_CIPHER_AES_128_CTR,
00093     MBEDTLS_CIPHER_AES_192_CTR,
00094     MBEDTLS_CIPHER_AES_256_CTR,
00095     MBEDTLS_CIPHER_AES_128_GCM,
00096     MBEDTLS_CIPHER_AES_192_GCM,
00097     MBEDTLS_CIPHER_AES_256_GCM,
00098     MBEDTLS_CIPHER_CAMELLIA_128_ECB,
00099     MBEDTLS_CIPHER_CAMELLIA_192_ECB,
00100     MBEDTLS_CIPHER_CAMELLIA_256_ECB,
00101     MBEDTLS_CIPHER_CAMELLIA_128_CBC,
00102     MBEDTLS_CIPHER_CAMELLIA_192_CBC,
00103     MBEDTLS_CIPHER_CAMELLIA_256_CBC,
00104     MBEDTLS_CIPHER_CAMELLIA_128_CFB128,
00105     MBEDTLS_CIPHER_CAMELLIA_192_CFB128,
00106     MBEDTLS_CIPHER_CAMELLIA_256_CFB128,
00107     MBEDTLS_CIPHER_CAMELLIA_128_CTR,
00108     MBEDTLS_CIPHER_CAMELLIA_192_CTR,
00109     MBEDTLS_CIPHER_CAMELLIA_256_CTR,
00110     MBEDTLS_CIPHER_CAMELLIA_128_GCM,
00111     MBEDTLS_CIPHER_CAMELLIA_192_GCM,
00112     MBEDTLS_CIPHER_CAMELLIA_256_GCM,
00113     MBEDTLS_CIPHER_DES_ECB,
00114     MBEDTLS_CIPHER_DES_CBC,
00115     MBEDTLS_CIPHER_DES_EDE_ECB,
00116     MBEDTLS_CIPHER_DES_EDE_CBC,
00117     MBEDTLS_CIPHER_DES_EDE3_ECB,
00118     MBEDTLS_CIPHER_DES_EDE3_CBC,
00119     MBEDTLS_CIPHER_BLOWFISH_ECB,
00120     MBEDTLS_CIPHER_BLOWFISH_CBC,
00121     MBEDTLS_CIPHER_BLOWFISH_CFB64,
00122     MBEDTLS_CIPHER_BLOWFISH_CTR,
00123     MBEDTLS_CIPHER_ARC4_128,
00124     MBEDTLS_CIPHER_AES_128_CCM,
00125     MBEDTLS_CIPHER_AES_192_CCM,
00126     MBEDTLS_CIPHER_AES_256_CCM,
00127     MBEDTLS_CIPHER_CAMELLIA_128_CCM,
00128     MBEDTLS_CIPHER_CAMELLIA_192_CCM,
00129     MBEDTLS_CIPHER_CAMELLIA_256_CCM,
00130 } mbedtls_cipher_type_t;
00131 
00132 typedef enum {
00133     MBEDTLS_MODE_NONE = 0,
00134     MBEDTLS_MODE_ECB,
00135     MBEDTLS_MODE_CBC,
00136     MBEDTLS_MODE_CFB,
00137     MBEDTLS_MODE_OFB, /* Unused! */
00138     MBEDTLS_MODE_CTR,
00139     MBEDTLS_MODE_GCM,
00140     MBEDTLS_MODE_STREAM,
00141     MBEDTLS_MODE_CCM,
00142 } mbedtls_cipher_mode_t;
00143 
00144 typedef enum {
00145     MBEDTLS_PADDING_PKCS7 = 0,     /**< PKCS7 padding (default)        */
00146     MBEDTLS_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding         */
00147     MBEDTLS_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding             */
00148     MBEDTLS_PADDING_ZEROS,         /**< zero padding (not reversible!) */
00149     MBEDTLS_PADDING_NONE,          /**< never pad (full blocks only)   */
00150 } mbedtls_cipher_padding_t ;
00151 
00152 typedef enum {
00153     MBEDTLS_OPERATION_NONE = -1,
00154     MBEDTLS_DECRYPT = 0,
00155     MBEDTLS_ENCRYPT,
00156 } mbedtls_operation_t;
00157 
00158 enum {
00159     /** Undefined key length */
00160     MBEDTLS_KEY_LENGTH_NONE = 0,
00161     /** Key length, in bits (including parity), for DES keys */
00162     MBEDTLS_KEY_LENGTH_DES  = 64,
00163     /** Key length, in bits (including parity), for DES in two key EDE */
00164     MBEDTLS_KEY_LENGTH_DES_EDE = 128,
00165     /** Key length, in bits (including parity), for DES in three-key EDE */
00166     MBEDTLS_KEY_LENGTH_DES_EDE3 = 192,
00167 };
00168 
00169 /** Maximum length of any IV, in bytes */
00170 #define MBEDTLS_MAX_IV_LENGTH      16
00171 /** Maximum block size of any cipher, in bytes */
00172 #define MBEDTLS_MAX_BLOCK_LENGTH   16
00173 
00174 /**
00175  * Base cipher information (opaque struct).
00176  */
00177 typedef struct mbedtls_cipher_base_t mbedtls_cipher_base_t;
00178 
00179 /**
00180  * CMAC context (opaque struct).
00181  */
00182 typedef struct mbedtls_cmac_context_t mbedtls_cmac_context_t;
00183 
00184 /**
00185  * Cipher information. Allows cipher functions to be called in a generic way.
00186  */
00187 typedef struct {
00188     /** Full cipher identifier (e.g. MBEDTLS_CIPHER_AES_256_CBC) */
00189     mbedtls_cipher_type_t type;
00190 
00191     /** Cipher mode (e.g. MBEDTLS_MODE_CBC) */
00192     mbedtls_cipher_mode_t mode;
00193 
00194     /** Cipher key length, in bits (default length for variable sized ciphers)
00195      *  (Includes parity bits for ciphers like DES) */
00196     unsigned int key_bitlen;
00197 
00198     /** Name of the cipher */
00199     const char * name;
00200 
00201     /** IV/NONCE size, in bytes.
00202      *  For cipher that accept many sizes: recommended size */
00203     unsigned int iv_size;
00204 
00205     /** Flags for variable IV size, variable key size, etc. */
00206     int flags;
00207 
00208     /** block size, in bytes */
00209     unsigned int block_size;
00210 
00211     /** Base cipher information and functions */
00212     const mbedtls_cipher_base_t *base;
00213 
00214 } mbedtls_cipher_info_t;
00215 
00216 /**
00217  * Generic cipher context.
00218  */
00219 typedef struct {
00220     /** Information about the associated cipher */
00221     const mbedtls_cipher_info_t *cipher_info;
00222 
00223     /** Key length to use */
00224     int key_bitlen;
00225 
00226     /** Operation that the context's key has been initialised for */
00227     mbedtls_operation_t operation;
00228 
00229 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
00230     /** Padding functions to use, if relevant for cipher mode */
00231     void (*add_padding)( unsigned char *output, size_t olen, size_t data_len );
00232     int (*get_padding)( unsigned char *input, size_t ilen, size_t *data_len );
00233 #endif
00234 
00235     /** Buffer for data that hasn't been encrypted yet */
00236     unsigned char unprocessed_data[MBEDTLS_MAX_BLOCK_LENGTH];
00237 
00238     /** Number of bytes that still need processing */
00239     size_t unprocessed_len;
00240 
00241     /** Current IV or NONCE_COUNTER for CTR-mode */
00242     unsigned char iv[MBEDTLS_MAX_IV_LENGTH];
00243 
00244     /** IV size in bytes (for ciphers with variable-length IVs) */
00245     size_t iv_size;
00246 
00247     /** Cipher-specific context */
00248     void *cipher_ctx;
00249 
00250 #if defined(MBEDTLS_CMAC_C)
00251     /** CMAC Specific context */
00252     mbedtls_cmac_context_t *cmac_ctx;
00253 #endif
00254 } mbedtls_cipher_context_t;
00255 
00256 /**
00257  * \brief Returns the list of ciphers supported by the generic cipher module.
00258  *
00259  * \return              a statically allocated array of ciphers, the last entry
00260  *                      is 0.
00261  */
00262 const int *mbedtls_cipher_list( void );
00263 
00264 /**
00265  * \brief               Returns the cipher information structure associated
00266  *                      with the given cipher name.
00267  *
00268  * \param cipher_name   Name of the cipher to search for.
00269  *
00270  * \return              the cipher information structure associated with the
00271  *                      given cipher_name, or NULL if not found.
00272  */
00273 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name );
00274 
00275 /**
00276  * \brief               Returns the cipher information structure associated
00277  *                      with the given cipher type.
00278  *
00279  * \param cipher_type   Type of the cipher to search for.
00280  *
00281  * \return              the cipher information structure associated with the
00282  *                      given cipher_type, or NULL if not found.
00283  */
00284 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type );
00285 
00286 /**
00287  * \brief               Returns the cipher information structure associated
00288  *                      with the given cipher id, key size and mode.
00289  *
00290  * \param cipher_id     Id of the cipher to search for
00291  *                      (e.g. MBEDTLS_CIPHER_ID_AES)
00292  * \param key_bitlen    Length of the key in bits
00293  * \param mode          Cipher mode (e.g. MBEDTLS_MODE_CBC)
00294  *
00295  * \return              the cipher information structure associated with the
00296  *                      given cipher_type, or NULL if not found.
00297  */
00298 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id,
00299                                               int key_bitlen,
00300                                               const mbedtls_cipher_mode_t mode );
00301 
00302 /**
00303  * \brief               Initialize a cipher_context (as NONE)
00304  */
00305 void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx );
00306 
00307 /**
00308  * \brief               Free and clear the cipher-specific context of ctx.
00309  *                      Freeing ctx itself remains the responsibility of the
00310  *                      caller.
00311  */
00312 void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx );
00313 
00314 /**
00315  * \brief               Initialises and fills the cipher context structure with
00316  *                      the appropriate values.
00317  *
00318  * \note                Currently also clears structure. In future versions you
00319  *                      will be required to call mbedtls_cipher_init() on the structure
00320  *                      first.
00321  *
00322  * \param ctx           context to initialise. May not be NULL.
00323  * \param cipher_info   cipher to use.
00324  *
00325  * \return              0 on success,
00326  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter failure,
00327  *                      MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the
00328  *                      cipher-specific context failed.
00329  */
00330 int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info );
00331 
00332 /**
00333  * \brief               Returns the block size of the given cipher.
00334  *
00335  * \param ctx           cipher's context. Must have been initialised.
00336  *
00337  * \return              size of the cipher's blocks, or 0 if ctx has not been
00338  *                      initialised.
00339  */
00340 static inline unsigned int mbedtls_cipher_get_block_size( const mbedtls_cipher_context_t *ctx )
00341 {
00342     if( NULL == ctx || NULL == ctx->cipher_info )
00343         return 0;
00344 
00345     return ctx->cipher_info->block_size;
00346 }
00347 
00348 /**
00349  * \brief               Returns the mode of operation for the cipher.
00350  *                      (e.g. MBEDTLS_MODE_CBC)
00351  *
00352  * \param ctx           cipher's context. Must have been initialised.
00353  *
00354  * \return              mode of operation, or MBEDTLS_MODE_NONE if ctx
00355  *                      has not been initialised.
00356  */
00357 static inline mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode( const mbedtls_cipher_context_t *ctx )
00358 {
00359     if( NULL == ctx || NULL == ctx->cipher_info )
00360         return MBEDTLS_MODE_NONE;
00361 
00362     return ctx->cipher_info->mode;
00363 }
00364 
00365 /**
00366  * \brief               Returns the size of the cipher's IV/NONCE in bytes.
00367  *
00368  * \param ctx           cipher's context. Must have been initialised.
00369  *
00370  * \return              If IV has not been set yet: (recommended) IV size
00371  *                      (0 for ciphers not using IV/NONCE).
00372  *                      If IV has already been set: actual size.
00373  */
00374 static inline int mbedtls_cipher_get_iv_size( const mbedtls_cipher_context_t *ctx )
00375 {
00376     if( NULL == ctx || NULL == ctx->cipher_info )
00377         return 0;
00378 
00379     if( ctx->iv_size != 0 )
00380         return (int) ctx->iv_size;
00381 
00382     return (int) ctx->cipher_info->iv_size;
00383 }
00384 
00385 /**
00386  * \brief               Returns the type of the given cipher.
00387  *
00388  * \param ctx           cipher's context. Must have been initialised.
00389  *
00390  * \return              type of the cipher, or MBEDTLS_CIPHER_NONE if ctx has
00391  *                      not been initialised.
00392  */
00393 static inline mbedtls_cipher_type_t mbedtls_cipher_get_type( const mbedtls_cipher_context_t *ctx )
00394 {
00395     if( NULL == ctx || NULL == ctx->cipher_info )
00396         return MBEDTLS_CIPHER_NONE;
00397 
00398     return ctx->cipher_info->type;
00399 }
00400 
00401 /**
00402  * \brief               Returns the name of the given cipher, as a string.
00403  *
00404  * \param ctx           cipher's context. Must have been initialised.
00405  *
00406  * \return              name of the cipher, or NULL if ctx was not initialised.
00407  */
00408 static inline const char *mbedtls_cipher_get_name( const mbedtls_cipher_context_t *ctx )
00409 {
00410     if( NULL == ctx || NULL == ctx->cipher_info )
00411         return 0;
00412 
00413     return ctx->cipher_info->name;
00414 }
00415 
00416 /**
00417  * \brief               Returns the key length of the cipher.
00418  *
00419  * \param ctx           cipher's context. Must have been initialised.
00420  *
00421  * \return              cipher's key length, in bits, or
00422  *                      MBEDTLS_KEY_LENGTH_NONE if ctx has not been
00423  *                      initialised.
00424  */
00425 static inline int mbedtls_cipher_get_key_bitlen( const mbedtls_cipher_context_t *ctx )
00426 {
00427     if( NULL == ctx || NULL == ctx->cipher_info )
00428         return MBEDTLS_KEY_LENGTH_NONE;
00429 
00430     return (int) ctx->cipher_info->key_bitlen;
00431 }
00432 
00433 /**
00434  * \brief               Returns the operation of the given cipher.
00435  *
00436  * \param ctx           cipher's context. Must have been initialised.
00437  *
00438  * \return              operation (MBEDTLS_ENCRYPT or MBEDTLS_DECRYPT),
00439  *                      or MBEDTLS_OPERATION_NONE if ctx has not been
00440  *                      initialised.
00441  */
00442 static inline mbedtls_operation_t mbedtls_cipher_get_operation( const mbedtls_cipher_context_t *ctx )
00443 {
00444     if( NULL == ctx || NULL == ctx->cipher_info )
00445         return MBEDTLS_OPERATION_NONE;
00446 
00447     return ctx->operation;
00448 }
00449 
00450 /**
00451  * \brief               Set the key to use with the given context.
00452  *
00453  * \param ctx           generic cipher context. May not be NULL. Must have been
00454  *                      initialised using cipher_context_from_type or
00455  *                      cipher_context_from_string.
00456  * \param key           The key to use.
00457  * \param key_bitlen    key length to use, in bits.
00458  * \param operation     Operation that the key will be used for, either
00459  *                      MBEDTLS_ENCRYPT or MBEDTLS_DECRYPT.
00460  *
00461  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
00462  *                      parameter verification fails or a cipher specific
00463  *                      error code.
00464  */
00465 int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key,
00466                    int key_bitlen, const mbedtls_operation_t operation );
00467 
00468 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
00469 /**
00470  * \brief               Set padding mode, for cipher modes that use padding.
00471  *                      (Default: PKCS7 padding.)
00472  *
00473  * \param ctx           generic cipher context
00474  * \param mode          padding mode
00475  *
00476  * \returns             0 on success, MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE
00477  *                      if selected padding mode is not supported, or
00478  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode
00479  *                      does not support padding.
00480  */
00481 int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t  mode );
00482 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
00483 
00484 /**
00485  * \brief               Set the initialization vector (IV) or nonce
00486  *
00487  * \param ctx           generic cipher context
00488  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00489  * \param iv_len        IV length for ciphers with variable-size IV;
00490  *                      discarded by ciphers with fixed-size IV.
00491  *
00492  * \returns             0 on success, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
00493  *
00494  * \note                Some ciphers don't use IVs nor NONCE. For these
00495  *                      ciphers, this function has no effect.
00496  */
00497 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
00498                    const unsigned char *iv, size_t iv_len );
00499 
00500 /**
00501  * \brief               Finish preparation of the given context
00502  *
00503  * \param ctx           generic cipher context
00504  *
00505  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
00506  *                      if parameter verification fails.
00507  */
00508 int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx );
00509 
00510 #if defined(MBEDTLS_GCM_C)
00511 /**
00512  * \brief               Add additional data (for AEAD ciphers).
00513  *                      Currently only supported with GCM.
00514  *                      Must be called exactly once, after mbedtls_cipher_reset().
00515  *
00516  * \param ctx           generic cipher context
00517  * \param ad            Additional data to use.
00518  * \param ad_len        Length of ad.
00519  *
00520  * \return              0 on success, or a specific error code.
00521  */
00522 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
00523                       const unsigned char *ad, size_t ad_len );
00524 #endif /* MBEDTLS_GCM_C */
00525 
00526 /**
00527  * \brief               Generic cipher update function. Encrypts/decrypts
00528  *                      using the given cipher context. Writes as many block
00529  *                      size'd blocks of data as possible to output. Any data
00530  *                      that cannot be written immediately will either be added
00531  *                      to the next block, or flushed when cipher_final is
00532  *                      called.
00533  *                      Exception: for MBEDTLS_MODE_ECB, expects single block
00534  *                                 in size (e.g. 16 bytes for AES)
00535  *
00536  * \param ctx           generic cipher context
00537  * \param input         buffer holding the input data
00538  * \param ilen          length of the input data
00539  * \param output        buffer for the output data. Should be able to hold at
00540  *                      least ilen + block_size. Cannot be the same buffer as
00541  *                      input!
00542  * \param olen          length of the output data, will be filled with the
00543  *                      actual number of bytes written.
00544  *
00545  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
00546  *                      parameter verification fails,
00547  *                      MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE on an
00548  *                      unsupported mode for a cipher or a cipher specific
00549  *                      error code.
00550  *
00551  * \note                If the underlying cipher is GCM, all calls to this
00552  *                      function, except the last one before mbedtls_cipher_finish(),
00553  *                      must have ilen a multiple of the block size.
00554  */
00555 int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input,
00556                    size_t ilen, unsigned char *output, size_t *olen );
00557 
00558 /**
00559  * \brief               Generic cipher finalisation function. If data still
00560  *                      needs to be flushed from an incomplete block, data
00561  *                      contained within it will be padded with the size of
00562  *                      the last block, and written to the output buffer.
00563  *
00564  * \param ctx           Generic cipher context
00565  * \param output        buffer to write data to. Needs block_size available.
00566  * \param olen          length of the data written to the output buffer.
00567  *
00568  * \returns             0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
00569  *                      parameter verification fails,
00570  *                      MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption
00571  *                      expected a full block but was not provided one,
00572  *                      MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
00573  *                      while decrypting or a cipher specific error code.
00574  */
00575 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
00576                    unsigned char *output, size_t *olen );
00577 
00578 #if defined(MBEDTLS_GCM_C)
00579 /**
00580  * \brief               Write tag for AEAD ciphers.
00581  *                      Currently only supported with GCM.
00582  *                      Must be called after mbedtls_cipher_finish().
00583  *
00584  * \param ctx           Generic cipher context
00585  * \param tag           buffer to write the tag
00586  * \param tag_len       Length of the tag to write
00587  *
00588  * \return              0 on success, or a specific error code.
00589  */
00590 int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
00591                       unsigned char *tag, size_t tag_len );
00592 
00593 /**
00594  * \brief               Check tag for AEAD ciphers.
00595  *                      Currently only supported with GCM.
00596  *                      Must be called after mbedtls_cipher_finish().
00597  *
00598  * \param ctx           Generic cipher context
00599  * \param tag           Buffer holding the tag
00600  * \param tag_len       Length of the tag to check
00601  *
00602  * \return              0 on success, or a specific error code.
00603  */
00604 int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
00605                       const unsigned char *tag, size_t tag_len );
00606 #endif /* MBEDTLS_GCM_C */
00607 
00608 /**
00609  * \brief               Generic all-in-one encryption/decryption
00610  *                      (for all ciphers except AEAD constructs).
00611  *
00612  * \param ctx           generic cipher context
00613  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00614  * \param iv_len        IV length for ciphers with variable-size IV;
00615  *                      discarded by ciphers with fixed-size IV.
00616  * \param input         buffer holding the input data
00617  * \param ilen          length of the input data
00618  * \param output        buffer for the output data. Should be able to hold at
00619  *                      least ilen + block_size. Cannot be the same buffer as
00620  *                      input!
00621  * \param olen          length of the output data, will be filled with the
00622  *                      actual number of bytes written.
00623  *
00624  * \note                Some ciphers don't use IVs nor NONCE. For these
00625  *                      ciphers, use iv = NULL and iv_len = 0.
00626  *
00627  * \returns             0 on success, or
00628  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
00629  *                      MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption
00630  *                      expected a full block but was not provided one, or
00631  *                      MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
00632  *                      while decrypting, or
00633  *                      a cipher specific error code.
00634  */
00635 int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx,
00636                   const unsigned char *iv, size_t iv_len,
00637                   const unsigned char *input, size_t ilen,
00638                   unsigned char *output, size_t *olen );
00639 
00640 #if defined(MBEDTLS_CIPHER_MODE_AEAD)
00641 /**
00642  * \brief               Generic autenticated encryption (AEAD ciphers).
00643  *
00644  * \param ctx           generic cipher context
00645  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00646  * \param iv_len        IV length for ciphers with variable-size IV;
00647  *                      discarded by ciphers with fixed-size IV.
00648  * \param ad            Additional data to authenticate.
00649  * \param ad_len        Length of ad.
00650  * \param input         buffer holding the input data
00651  * \param ilen          length of the input data
00652  * \param output        buffer for the output data.
00653  *                      Should be able to hold at least ilen.
00654  * \param olen          length of the output data, will be filled with the
00655  *                      actual number of bytes written.
00656  * \param tag           buffer for the authentication tag
00657  * \param tag_len       desired tag length
00658  *
00659  * \returns             0 on success, or
00660  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
00661  *                      a cipher specific error code.
00662  */
00663 int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx,
00664                          const unsigned char *iv, size_t iv_len,
00665                          const unsigned char *ad, size_t ad_len,
00666                          const unsigned char *input, size_t ilen,
00667                          unsigned char *output, size_t *olen,
00668                          unsigned char *tag, size_t tag_len );
00669 
00670 /**
00671  * \brief               Generic autenticated decryption (AEAD ciphers).
00672  *
00673  * \param ctx           generic cipher context
00674  * \param iv            IV to use (or NONCE_COUNTER for CTR-mode ciphers)
00675  * \param iv_len        IV length for ciphers with variable-size IV;
00676  *                      discarded by ciphers with fixed-size IV.
00677  * \param ad            Additional data to be authenticated.
00678  * \param ad_len        Length of ad.
00679  * \param input         buffer holding the input data
00680  * \param ilen          length of the input data
00681  * \param output        buffer for the output data.
00682  *                      Should be able to hold at least ilen.
00683  * \param olen          length of the output data, will be filled with the
00684  *                      actual number of bytes written.
00685  * \param tag           buffer holding the authentication tag
00686  * \param tag_len       length of the authentication tag
00687  *
00688  * \returns             0 on success, or
00689  *                      MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
00690  *                      MBEDTLS_ERR_CIPHER_AUTH_FAILED if data isn't authentic,
00691  *                      or a cipher specific error code.
00692  *
00693  * \note                If the data is not authentic, then the output buffer
00694  *                      is zeroed out to prevent the unauthentic plaintext to
00695  *                      be used by mistake, making this interface safer.
00696  */
00697 int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
00698                          const unsigned char *iv, size_t iv_len,
00699                          const unsigned char *ad, size_t ad_len,
00700                          const unsigned char *input, size_t ilen,
00701                          unsigned char *output, size_t *olen,
00702                          const unsigned char *tag, size_t tag_len );
00703 #endif /* MBEDTLS_CIPHER_MODE_AEAD */
00704 
00705 #ifdef __cplusplus
00706 }
00707 #endif
00708 
00709 #endif /* MBEDTLS_CIPHER_H */