cipher.h

00001 /**
00002  * \file cipher.h
00003  *
00004  * \brief This file contains an abstraction interface for use with the cipher
00005  * primitives provided by the library. It provides a common interface to all of
00006  * the available cipher operations.
00007  *
00008  * \author Adriaan de Jong <dejong@fox-it.com>
00009  */
00010 /*
00011  *  Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
00012  *  SPDX-License-Identifier: Apache-2.0
00013  *
00014  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00015  *  not use this file except in compliance with the License.
00016  *  You may obtain a copy of the License at
00017  *
00018  *  http://www.apache.org/licenses/LICENSE-2.0
00019  *
00020  *  Unless required by applicable law or agreed to in writing, software
00021  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00022  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00023  *  See the License for the specific language governing permissions and
00024  *  limitations under the License.
00025  *
00026  *  This file is part of Mbed TLS (https://tls.mbed.org)
00027  */
00028 
00029 #ifndef MBEDTLS_CIPHER_H
00030 #define MBEDTLS_CIPHER_H
00031 
00032 #if !defined(MBEDTLS_CONFIG_FILE)
00033 #include "config.h"
00034 #else
00035 #include MBEDTLS_CONFIG_FILE
00036 #endif
00037 
00038 #include <stddef.h>
00039 
00040 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CCM_C)
00041 #define MBEDTLS_CIPHER_MODE_AEAD
00042 #endif
00043 
00044 #if defined(MBEDTLS_CIPHER_MODE_CBC)
00045 #define MBEDTLS_CIPHER_MODE_WITH_PADDING
00046 #endif
00047 
00048 #if defined(MBEDTLS_ARC4_C)
00049 #define MBEDTLS_CIPHER_MODE_STREAM
00050 #endif
00051 
00052 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
00053     !defined(inline) && !defined(__cplusplus)
00054 #define inline __inline
00055 #endif
00056 
00057 #define MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE  -0x6080  /**< The selected feature is not available. */
00058 #define MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA       -0x6100  /**< Bad input parameters. */
00059 #define MBEDTLS_ERR_CIPHER_ALLOC_FAILED         -0x6180  /**< Failed to allocate memory. */
00060 #define MBEDTLS_ERR_CIPHER_INVALID_PADDING      -0x6200  /**< Input data contains invalid padding and is rejected. */
00061 #define MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED  -0x6280  /**< Decryption of block requires a full block. */
00062 #define MBEDTLS_ERR_CIPHER_AUTH_FAILED          -0x6300  /**< Authentication failed (for AEAD modes). */
00063 #define MBEDTLS_ERR_CIPHER_INVALID_CONTEXT      -0x6380  /**< The context is invalid. For example, because it was freed. */
00064 #define MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED      -0x6400  /**< Cipher hardware accelerator failed. */
00065 
00066 #define MBEDTLS_CIPHER_VARIABLE_IV_LEN     0x01    /**< Cipher accepts IVs of variable length. */
00067 #define MBEDTLS_CIPHER_VARIABLE_KEY_LEN    0x02    /**< Cipher accepts keys of variable length. */
00068 
00069 #ifdef __cplusplus
00070 extern "C" {
00071 #endif
00072 
00073 /**
00074  * \brief     Supported cipher types.
00075  *
00076  * \warning   RC4 and DES are considered weak ciphers and their use
00077  *            constitutes a security risk. Arm recommends considering stronger
00078  *            ciphers instead.
00079  */
00080 typedef enum {
00081     MBEDTLS_CIPHER_ID_NONE = 0,  /**< Placeholder to mark the end of cipher ID lists. */
00082     MBEDTLS_CIPHER_ID_NULL,      /**< The identity cipher, treated as a stream cipher. */
00083     MBEDTLS_CIPHER_ID_AES,       /**< The AES cipher. */
00084     MBEDTLS_CIPHER_ID_DES,       /**< The DES cipher. */
00085     MBEDTLS_CIPHER_ID_3DES,      /**< The Triple DES cipher. */
00086     MBEDTLS_CIPHER_ID_CAMELLIA,  /**< The Camellia cipher. */
00087     MBEDTLS_CIPHER_ID_BLOWFISH,  /**< The Blowfish cipher. */
00088     MBEDTLS_CIPHER_ID_ARC4,      /**< The RC4 cipher. */
00089     MBEDTLS_CIPHER_ID_ARIA,      /**< The Aria cipher. */
00090 } mbedtls_cipher_id_t;
00091 
00092 /**
00093  * \brief     Supported {cipher type, cipher mode} pairs.
00094  *
00095  * \warning   RC4 and DES are considered weak ciphers and their use
00096  *            constitutes a security risk. Arm recommends considering stronger
00097  *            ciphers instead.
00098  */
00099 typedef enum {
00100     MBEDTLS_CIPHER_NONE = 0,             /**< Placeholder to mark the end of cipher-pair lists. */
00101     MBEDTLS_CIPHER_NULL,                 /**< The identity stream cipher. */
00102     MBEDTLS_CIPHER_AES_128_ECB,          /**< AES cipher with 128-bit ECB mode. */
00103     MBEDTLS_CIPHER_AES_192_ECB,          /**< AES cipher with 192-bit ECB mode. */
00104     MBEDTLS_CIPHER_AES_256_ECB,          /**< AES cipher with 256-bit ECB mode. */
00105     MBEDTLS_CIPHER_AES_128_CBC,          /**< AES cipher with 128-bit CBC mode. */
00106     MBEDTLS_CIPHER_AES_192_CBC,          /**< AES cipher with 192-bit CBC mode. */
00107     MBEDTLS_CIPHER_AES_256_CBC,          /**< AES cipher with 256-bit CBC mode. */
00108     MBEDTLS_CIPHER_AES_128_CFB128,       /**< AES cipher with 128-bit CFB128 mode. */
00109     MBEDTLS_CIPHER_AES_192_CFB128,       /**< AES cipher with 192-bit CFB128 mode. */
00110     MBEDTLS_CIPHER_AES_256_CFB128,       /**< AES cipher with 256-bit CFB128 mode. */
00111     MBEDTLS_CIPHER_AES_128_CTR,          /**< AES cipher with 128-bit CTR mode. */
00112     MBEDTLS_CIPHER_AES_192_CTR,          /**< AES cipher with 192-bit CTR mode. */
00113     MBEDTLS_CIPHER_AES_256_CTR,          /**< AES cipher with 256-bit CTR mode. */
00114     MBEDTLS_CIPHER_AES_128_GCM,          /**< AES cipher with 128-bit GCM mode. */
00115     MBEDTLS_CIPHER_AES_192_GCM,          /**< AES cipher with 192-bit GCM mode. */
00116     MBEDTLS_CIPHER_AES_256_GCM,          /**< AES cipher with 256-bit GCM mode. */
00117     MBEDTLS_CIPHER_CAMELLIA_128_ECB,     /**< Camellia cipher with 128-bit ECB mode. */
00118     MBEDTLS_CIPHER_CAMELLIA_192_ECB,     /**< Camellia cipher with 192-bit ECB mode. */
00119     MBEDTLS_CIPHER_CAMELLIA_256_ECB,     /**< Camellia cipher with 256-bit ECB mode. */
00120     MBEDTLS_CIPHER_CAMELLIA_128_CBC,     /**< Camellia cipher with 128-bit CBC mode. */
00121     MBEDTLS_CIPHER_CAMELLIA_192_CBC,     /**< Camellia cipher with 192-bit CBC mode. */
00122     MBEDTLS_CIPHER_CAMELLIA_256_CBC,     /**< Camellia cipher with 256-bit CBC mode. */
00123     MBEDTLS_CIPHER_CAMELLIA_128_CFB128,  /**< Camellia cipher with 128-bit CFB128 mode. */
00124     MBEDTLS_CIPHER_CAMELLIA_192_CFB128,  /**< Camellia cipher with 192-bit CFB128 mode. */
00125     MBEDTLS_CIPHER_CAMELLIA_256_CFB128,  /**< Camellia cipher with 256-bit CFB128 mode. */
00126     MBEDTLS_CIPHER_CAMELLIA_128_CTR,     /**< Camellia cipher with 128-bit CTR mode. */
00127     MBEDTLS_CIPHER_CAMELLIA_192_CTR,     /**< Camellia cipher with 192-bit CTR mode. */
00128     MBEDTLS_CIPHER_CAMELLIA_256_CTR,     /**< Camellia cipher with 256-bit CTR mode. */
00129     MBEDTLS_CIPHER_CAMELLIA_128_GCM,     /**< Camellia cipher with 128-bit GCM mode. */
00130     MBEDTLS_CIPHER_CAMELLIA_192_GCM,     /**< Camellia cipher with 192-bit GCM mode. */
00131     MBEDTLS_CIPHER_CAMELLIA_256_GCM,     /**< Camellia cipher with 256-bit GCM mode. */
00132     MBEDTLS_CIPHER_DES_ECB,              /**< DES cipher with ECB mode. */
00133     MBEDTLS_CIPHER_DES_CBC,              /**< DES cipher with CBC mode. */
00134     MBEDTLS_CIPHER_DES_EDE_ECB,          /**< DES cipher with EDE ECB mode. */
00135     MBEDTLS_CIPHER_DES_EDE_CBC,          /**< DES cipher with EDE CBC mode. */
00136     MBEDTLS_CIPHER_DES_EDE3_ECB,         /**< DES cipher with EDE3 ECB mode. */
00137     MBEDTLS_CIPHER_DES_EDE3_CBC,         /**< DES cipher with EDE3 CBC mode. */
00138     MBEDTLS_CIPHER_BLOWFISH_ECB,         /**< Blowfish cipher with ECB mode. */
00139     MBEDTLS_CIPHER_BLOWFISH_CBC,         /**< Blowfish cipher with CBC mode. */
00140     MBEDTLS_CIPHER_BLOWFISH_CFB64,       /**< Blowfish cipher with CFB64 mode. */
00141     MBEDTLS_CIPHER_BLOWFISH_CTR,         /**< Blowfish cipher with CTR mode. */
00142     MBEDTLS_CIPHER_ARC4_128,             /**< RC4 cipher with 128-bit mode. */
00143     MBEDTLS_CIPHER_AES_128_CCM,          /**< AES cipher with 128-bit CCM mode. */
00144     MBEDTLS_CIPHER_AES_192_CCM,          /**< AES cipher with 192-bit CCM mode. */
00145     MBEDTLS_CIPHER_AES_256_CCM,          /**< AES cipher with 256-bit CCM mode. */
00146     MBEDTLS_CIPHER_CAMELLIA_128_CCM,     /**< Camellia cipher with 128-bit CCM mode. */
00147     MBEDTLS_CIPHER_CAMELLIA_192_CCM,     /**< Camellia cipher with 192-bit CCM mode. */
00148     MBEDTLS_CIPHER_CAMELLIA_256_CCM,     /**< Camellia cipher with 256-bit CCM mode. */
00149     MBEDTLS_CIPHER_ARIA_128_ECB,         /**< Aria cipher with 128-bit key and ECB mode. */
00150     MBEDTLS_CIPHER_ARIA_192_ECB,         /**< Aria cipher with 192-bit key and ECB mode. */
00151     MBEDTLS_CIPHER_ARIA_256_ECB,         /**< Aria cipher with 256-bit key and ECB mode. */
00152     MBEDTLS_CIPHER_ARIA_128_CBC,         /**< Aria cipher with 128-bit key and CBC mode. */
00153     MBEDTLS_CIPHER_ARIA_192_CBC,         /**< Aria cipher with 192-bit key and CBC mode. */
00154     MBEDTLS_CIPHER_ARIA_256_CBC,         /**< Aria cipher with 256-bit key and CBC mode. */
00155     MBEDTLS_CIPHER_ARIA_128_CFB128,      /**< Aria cipher with 128-bit key and CFB-128 mode. */
00156     MBEDTLS_CIPHER_ARIA_192_CFB128,      /**< Aria cipher with 192-bit key and CFB-128 mode. */
00157     MBEDTLS_CIPHER_ARIA_256_CFB128,      /**< Aria cipher with 256-bit key and CFB-128 mode. */
00158     MBEDTLS_CIPHER_ARIA_128_CTR,         /**< Aria cipher with 128-bit key and CTR mode. */
00159     MBEDTLS_CIPHER_ARIA_192_CTR,         /**< Aria cipher with 192-bit key and CTR mode. */
00160     MBEDTLS_CIPHER_ARIA_256_CTR,         /**< Aria cipher with 256-bit key and CTR mode. */
00161     MBEDTLS_CIPHER_ARIA_128_GCM,         /**< Aria cipher with 128-bit key and GCM mode. */
00162     MBEDTLS_CIPHER_ARIA_192_GCM,         /**< Aria cipher with 192-bit key and GCM mode. */
00163     MBEDTLS_CIPHER_ARIA_256_GCM,         /**< Aria cipher with 256-bit key and GCM mode. */
00164     MBEDTLS_CIPHER_ARIA_128_CCM,         /**< Aria cipher with 128-bit key and CCM mode. */
00165     MBEDTLS_CIPHER_ARIA_192_CCM,         /**< Aria cipher with 192-bit key and CCM mode. */
00166     MBEDTLS_CIPHER_ARIA_256_CCM,         /**< Aria cipher with 256-bit key and CCM mode. */
00167 } mbedtls_cipher_type_t;
00168 
00169 /** Supported cipher modes. */
00170 typedef enum {
00171     MBEDTLS_MODE_NONE = 0,               /**< None. */
00172     MBEDTLS_MODE_ECB,                    /**< The ECB cipher mode. */
00173     MBEDTLS_MODE_CBC,                    /**< The CBC cipher mode. */
00174     MBEDTLS_MODE_CFB,                    /**< The CFB cipher mode. */
00175     MBEDTLS_MODE_OFB,                    /**< The OFB cipher mode - unsupported. */
00176     MBEDTLS_MODE_CTR,                    /**< The CTR cipher mode. */
00177     MBEDTLS_MODE_GCM,                    /**< The GCM cipher mode. */
00178     MBEDTLS_MODE_STREAM,                 /**< The stream cipher mode. */
00179     MBEDTLS_MODE_CCM,                    /**< The CCM cipher mode. */
00180 } mbedtls_cipher_mode_t;
00181 
00182 /** Supported cipher padding types. */
00183 typedef enum {
00184     MBEDTLS_PADDING_PKCS7 = 0,     /**< PKCS7 padding (default).        */
00185     MBEDTLS_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding.         */
00186     MBEDTLS_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding.             */
00187     MBEDTLS_PADDING_ZEROS,         /**< Zero padding (not reversible). */
00188     MBEDTLS_PADDING_NONE,          /**< Never pad (full blocks only).   */
00189 } mbedtls_cipher_padding_t;
00190 
00191 /** Type of operation. */
00192 typedef enum {
00193     MBEDTLS_OPERATION_NONE = -1,
00194     MBEDTLS_DECRYPT = 0,
00195     MBEDTLS_ENCRYPT,
00196 } mbedtls_operation_t;
00197 
00198 enum {
00199     /** Undefined key length. */
00200     MBEDTLS_KEY_LENGTH_NONE = 0,
00201     /** Key length, in bits (including parity), for DES keys. */
00202     MBEDTLS_KEY_LENGTH_DES  = 64,
00203     /** Key length in bits, including parity, for DES in two-key EDE. */
00204     MBEDTLS_KEY_LENGTH_DES_EDE = 128,
00205     /** Key length in bits, including parity, for DES in three-key EDE. */
00206     MBEDTLS_KEY_LENGTH_DES_EDE3 = 192,
00207 };
00208 
00209 /** Maximum length of any IV, in Bytes. */
00210 #define MBEDTLS_MAX_IV_LENGTH      16
00211 /** Maximum block size of any cipher, in Bytes. */
00212 #define MBEDTLS_MAX_BLOCK_LENGTH   16
00213 
00214 /**
00215  * Base cipher information (opaque struct).
00216  */
00217 typedef struct mbedtls_cipher_base_t mbedtls_cipher_base_t;
00218 
00219 /**
00220  * CMAC context (opaque struct).
00221  */
00222 typedef struct mbedtls_cmac_context_t mbedtls_cmac_context_t;
00223 
00224 /**
00225  * Cipher information. Allows calling cipher functions
00226  * in a generic way.
00227  */
00228 typedef struct {
00229     /** Full cipher identifier. For example,
00230      * MBEDTLS_CIPHER_AES_256_CBC.
00231      */
00232     mbedtls_cipher_type_t type;
00233 
00234     /** The cipher mode. For example, MBEDTLS_MODE_CBC. */
00235     mbedtls_cipher_mode_t mode;
00236 
00237     /** The cipher key length, in bits. This is the
00238      * default length for variable sized ciphers.
00239      * Includes parity bits for ciphers like DES.
00240      */
00241     unsigned int key_bitlen;
00242 
00243     /** Name of the cipher. */
00244     const char * name;
00245 
00246     /** IV or nonce size, in Bytes.
00247      * For ciphers that accept variable IV sizes,
00248      * this is the recommended size.
00249      */
00250     unsigned int iv_size;
00251 
00252     /** Bitflag comprised of MBEDTLS_CIPHER_VARIABLE_IV_LEN and
00253      *  MBEDTLS_CIPHER_VARIABLE_KEY_LEN indicating whether the
00254      *  cipher supports variable IV or variable key sizes, respectively.
00255      */
00256     int flags;
00257 
00258     /** The block size, in Bytes. */
00259     unsigned int block_size;
00260 
00261     /** Struct for base cipher information and functions. */
00262     const mbedtls_cipher_base_t *base;
00263 
00264 } mbedtls_cipher_info_t;
00265 
00266 /**
00267  * Generic cipher context.
00268  */
00269 typedef struct {
00270     /** Information about the associated cipher. */
00271     const mbedtls_cipher_info_t *cipher_info;
00272 
00273     /** Key length to use. */
00274     int key_bitlen;
00275 
00276     /** Operation that the key of the context has been
00277      * initialized for.
00278      */
00279     mbedtls_operation_t operation;
00280 
00281 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
00282     /** Padding functions to use, if relevant for
00283      * the specific cipher mode.
00284      */
00285     void (*add_padding)( unsigned char *output, size_t olen, size_t data_len );
00286     int (*get_padding)( unsigned char *input, size_t ilen, size_t *data_len );
00287 #endif
00288 
00289     /** Buffer for input that has not been processed yet. */
00290     unsigned char unprocessed_data[MBEDTLS_MAX_BLOCK_LENGTH];
00291 
00292     /** Number of Bytes that have not been processed yet. */
00293     size_t unprocessed_len;
00294 
00295     /** Current IV or NONCE_COUNTER for CTR-mode. */
00296     unsigned char iv[MBEDTLS_MAX_IV_LENGTH];
00297 
00298     /** IV size in Bytes, for ciphers with variable-length IVs. */
00299     size_t iv_size;
00300 
00301     /** The cipher-specific context. */
00302     void *cipher_ctx;
00303 
00304 #if defined(MBEDTLS_CMAC_C)
00305     /** CMAC-specific context. */
00306     mbedtls_cmac_context_t *cmac_ctx;
00307 #endif
00308 } mbedtls_cipher_context_t;
00309 
00310 /**
00311  * \brief This function retrieves the list of ciphers supported by the generic
00312  * cipher module.
00313  *
00314  * \return      A statically-allocated array of ciphers. The last entry
00315  *              is zero.
00316  */
00317 const int *mbedtls_cipher_list( void );
00318 
00319 /**
00320  * \brief               This function retrieves the cipher-information
00321  *                      structure associated with the given cipher name.
00322  *
00323  * \param cipher_name   Name of the cipher to search for.
00324  *
00325  * \return              The cipher information structure associated with the
00326  *                      given \p cipher_name.
00327  * \return              NULL if the associated cipher information is not found.
00328  */
00329 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name );
00330 
00331 /**
00332  * \brief               This function retrieves the cipher-information
00333  *                      structure associated with the given cipher type.
00334  *
00335  * \param cipher_type   Type of the cipher to search for.
00336  *
00337  * \return              The cipher information structure associated with the
00338  *                      given \p cipher_type.
00339  * \return              NULL if the associated cipher information is not found.
00340  */
00341 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type );
00342 
00343 /**
00344  * \brief               This function retrieves the cipher-information
00345  *                      structure associated with the given cipher ID,
00346  *                      key size and mode.
00347  *
00348  * \param cipher_id     The ID of the cipher to search for. For example,
00349  *                      #MBEDTLS_CIPHER_ID_AES.
00350  * \param key_bitlen    The length of the key in bits.
00351  * \param mode          The cipher mode. For example, #MBEDTLS_MODE_CBC.
00352  *
00353  * \return              The cipher information structure associated with the
00354  *                      given \p cipher_id.
00355  * \return              NULL if the associated cipher information is not found.
00356  */
00357 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id,
00358                                               int key_bitlen,
00359                                               const mbedtls_cipher_mode_t mode );
00360 
00361 /**
00362  * \brief               This function initializes a \p cipher_context as NONE.
00363  */
00364 void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx );
00365 
00366 /**
00367  * \brief               This function frees and clears the cipher-specific
00368  *                      context of \p ctx. Freeing \p ctx itself remains the
00369  *                      responsibility of the caller.
00370  */
00371 void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx );
00372 
00373 
00374 /**
00375  * \brief               This function initializes and fills the cipher-context
00376  *                      structure with the appropriate values. It also clears
00377  *                      the structure.
00378  *
00379  * \param ctx           The context to initialize. May not be NULL.
00380  * \param cipher_info   The cipher to use.
00381  *
00382  * \return              \c 0 on success.
00383  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00384  *                      parameter-verification failure.
00385  * \return              #MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the
00386  *                      cipher-specific context fails.
00387  *
00388  * \internal Currently, the function also clears the structure.
00389  * In future versions, the caller will be required to call
00390  * mbedtls_cipher_init() on the structure first.
00391  */
00392 int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info );
00393 
00394 /**
00395  * \brief        This function returns the block size of the given cipher.
00396  *
00397  * \param ctx    The context of the cipher. Must be initialized.
00398  *
00399  * \return       The size of the blocks of the cipher.
00400  * \return       0 if \p ctx has not been initialized.
00401  */
00402 static inline unsigned int mbedtls_cipher_get_block_size( const mbedtls_cipher_context_t *ctx )
00403 {
00404     if( NULL == ctx || NULL == ctx->cipher_info )
00405         return 0;
00406 
00407     return ctx->cipher_info->block_size;
00408 }
00409 
00410 /**
00411  * \brief        This function returns the mode of operation for
00412  *               the cipher. For example, MBEDTLS_MODE_CBC.
00413  *
00414  * \param ctx    The context of the cipher. Must be initialized.
00415  *
00416  * \return       The mode of operation.
00417  * \return       #MBEDTLS_MODE_NONE if \p ctx has not been initialized.
00418  */
00419 static inline mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode( const mbedtls_cipher_context_t *ctx )
00420 {
00421     if( NULL == ctx || NULL == ctx->cipher_info )
00422         return MBEDTLS_MODE_NONE;
00423 
00424     return ctx->cipher_info->mode;
00425 }
00426 
00427 /**
00428  * \brief       This function returns the size of the IV or nonce
00429  *              of the cipher, in Bytes.
00430  *
00431  * \param ctx   The context of the cipher. Must be initialized.
00432  *
00433  * \return      The recommended IV size if no IV has been set.
00434  * \return      \c 0 for ciphers not using an IV or a nonce.
00435  * \return      The actual size if an IV has been set.
00436  */
00437 static inline int mbedtls_cipher_get_iv_size( const mbedtls_cipher_context_t *ctx )
00438 {
00439     if( NULL == ctx || NULL == ctx->cipher_info )
00440         return 0;
00441 
00442     if( ctx->iv_size != 0 )
00443         return (int) ctx->iv_size;
00444 
00445     return (int) ctx->cipher_info->iv_size;
00446 }
00447 
00448 /**
00449  * \brief               This function returns the type of the given cipher.
00450  *
00451  * \param ctx           The context of the cipher. Must be initialized.
00452  *
00453  * \return              The type of the cipher.
00454  * \return              #MBEDTLS_CIPHER_NONE if \p ctx has not been initialized.
00455  */
00456 static inline mbedtls_cipher_type_t mbedtls_cipher_get_type( const mbedtls_cipher_context_t *ctx )
00457 {
00458     if( NULL == ctx || NULL == ctx->cipher_info )
00459         return MBEDTLS_CIPHER_NONE;
00460 
00461     return ctx->cipher_info->type;
00462 }
00463 
00464 /**
00465  * \brief               This function returns the name of the given cipher
00466  *                      as a string.
00467  *
00468  * \param ctx           The context of the cipher. Must be initialized.
00469  *
00470  * \return              The name of the cipher.
00471  * \return              NULL if \p ctx has not been not initialized.
00472  */
00473 static inline const char *mbedtls_cipher_get_name( const mbedtls_cipher_context_t *ctx )
00474 {
00475     if( NULL == ctx || NULL == ctx->cipher_info )
00476         return 0;
00477 
00478     return ctx->cipher_info->name;
00479 }
00480 
00481 /**
00482  * \brief               This function returns the key length of the cipher.
00483  *
00484  * \param ctx           The context of the cipher. Must be initialized.
00485  *
00486  * \return              The key length of the cipher in bits.
00487  * \return              #MBEDTLS_KEY_LENGTH_NONE if ctx \p has not been
00488  *                      initialized.
00489  */
00490 static inline int mbedtls_cipher_get_key_bitlen( const mbedtls_cipher_context_t *ctx )
00491 {
00492     if( NULL == ctx || NULL == ctx->cipher_info )
00493         return MBEDTLS_KEY_LENGTH_NONE;
00494 
00495     return (int) ctx->cipher_info->key_bitlen;
00496 }
00497 
00498 /**
00499  * \brief          This function returns the operation of the given cipher.
00500  *
00501  * \param ctx      The context of the cipher. Must be initialized.
00502  *
00503  * \return         The type of operation: #MBEDTLS_ENCRYPT or #MBEDTLS_DECRYPT.
00504  * \return         #MBEDTLS_OPERATION_NONE if \p ctx has not been initialized.
00505  */
00506 static inline mbedtls_operation_t mbedtls_cipher_get_operation( const mbedtls_cipher_context_t *ctx )
00507 {
00508     if( NULL == ctx || NULL == ctx->cipher_info )
00509         return MBEDTLS_OPERATION_NONE;
00510 
00511     return ctx->operation;
00512 }
00513 
00514 /**
00515  * \brief               This function sets the key to use with the given context.
00516  *
00517  * \param ctx           The generic cipher context. May not be NULL. Must have
00518  *                      been initialized using mbedtls_cipher_info_from_type()
00519  *                      or mbedtls_cipher_info_from_string().
00520  * \param key           The key to use.
00521  * \param key_bitlen    The key length to use, in bits.
00522  * \param operation     The operation that the key will be used for:
00523  *                      #MBEDTLS_ENCRYPT or #MBEDTLS_DECRYPT.
00524  *
00525  * \return              \c 0 on success.
00526  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00527  *                      parameter-verification failure.
00528  * \return              A cipher-specific error code on failure.
00529  */
00530 int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key,
00531                    int key_bitlen, const mbedtls_operation_t operation );
00532 
00533 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
00534 /**
00535  * \brief               This function sets the padding mode, for cipher modes
00536  *                      that use padding.
00537  *
00538  *                      The default passing mode is PKCS7 padding.
00539  *
00540  * \param ctx           The generic cipher context.
00541  * \param mode          The padding mode.
00542  *
00543  * \return              \c 0 on success.
00544  * \return              #MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE
00545  *                      if the selected padding mode is not supported.
00546  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode
00547  *                      does not support padding.
00548  */
00549 int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t mode );
00550 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
00551 
00552 /**
00553  * \brief           This function sets the initialization vector (IV)
00554  *                  or nonce.
00555  *
00556  * \note            Some ciphers do not use IVs nor nonce. For these
00557  *                  ciphers, this function has no effect.
00558  *
00559  * \param ctx       The generic cipher context.
00560  * \param iv        The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
00561  * \param iv_len    The IV length for ciphers with variable-size IV.
00562  *                  This parameter is discarded by ciphers with fixed-size IV.
00563  *
00564  * \return          \c 0 on success.
00565  * \return          #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00566  *                  parameter-verification failure.
00567  */
00568 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
00569                    const unsigned char *iv, size_t iv_len );
00570 
00571 /**
00572  * \brief         This function resets the cipher state.
00573  *
00574  * \param ctx     The generic cipher context.
00575  *
00576  * \return        \c 0 on success.
00577  * \return        #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00578  *                parameter-verification failure.
00579  */
00580 int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx );
00581 
00582 #if defined(MBEDTLS_GCM_C)
00583 /**
00584  * \brief               This function adds additional data for AEAD ciphers.
00585  *                      Only supported with GCM. Must be called
00586  *                      exactly once, after mbedtls_cipher_reset().
00587  *
00588  * \param ctx           The generic cipher context.
00589  * \param ad            The additional data to use.
00590  * \param ad_len        the Length of \p ad.
00591  *
00592  * \return              \c 0 on success.
00593  * \return              A specific error code on failure.
00594  */
00595 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
00596                       const unsigned char *ad, size_t ad_len );
00597 #endif /* MBEDTLS_GCM_C */
00598 
00599 /**
00600  * \brief               The generic cipher update function. It encrypts or
00601  *                      decrypts using the given cipher context. Writes as
00602  *                      many block-sized blocks of data as possible to output.
00603  *                      Any data that cannot be written immediately is either
00604  *                      added to the next block, or flushed when
00605  *                      mbedtls_cipher_finish() is called.
00606  *                      Exception: For MBEDTLS_MODE_ECB, expects a single block
00607  *                      in size. For example, 16 Bytes for AES.
00608  *
00609  * \note                If the underlying cipher is used in GCM mode, all calls
00610  *                      to this function, except for the last one before
00611  *                      mbedtls_cipher_finish(), must have \p ilen as a
00612  *                      multiple of the block size of the cipher.
00613  *
00614  * \param ctx           The generic cipher context.
00615  * \param input         The buffer holding the input data.
00616  * \param ilen          The length of the input data.
00617  * \param output        The buffer for the output data. Must be able to hold at
00618  *                      least \p ilen + block_size. Must not be the same buffer
00619  *                      as input.
00620  * \param olen          The length of the output data, to be updated with the
00621  *                      actual number of Bytes written.
00622  *
00623  * \return              \c 0 on success.
00624  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00625  *                      parameter-verification failure.
00626  * \return              #MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE on an
00627  *                      unsupported mode for a cipher.
00628  * \return              A cipher-specific error code on failure.
00629  */
00630 int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input,
00631                    size_t ilen, unsigned char *output, size_t *olen );
00632 
00633 /**
00634  * \brief               The generic cipher finalization function. If data still
00635  *                      needs to be flushed from an incomplete block, the data
00636  *                      contained in it is padded to the size of
00637  *                      the last block, and written to the \p output buffer.
00638  *
00639  * \param ctx           The generic cipher context.
00640  * \param output        The buffer to write data to. Needs block_size available.
00641  * \param olen          The length of the data written to the \p output buffer.
00642  *
00643  * \return              \c 0 on success.
00644  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00645  *                      parameter-verification failure.
00646  * \return              #MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED on decryption
00647  *                      expecting a full block but not receiving one.
00648  * \return              #MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
00649  *                      while decrypting.
00650  * \return              A cipher-specific error code on failure.
00651  */
00652 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
00653                    unsigned char *output, size_t *olen );
00654 
00655 #if defined(MBEDTLS_GCM_C)
00656 /**
00657  * \brief               This function writes a tag for AEAD ciphers.
00658  *                      Only supported with GCM.
00659  *                      Must be called after mbedtls_cipher_finish().
00660  *
00661  * \param ctx           The generic cipher context.
00662  * \param tag           The buffer to write the tag to.
00663  * \param tag_len       The length of the tag to write.
00664  *
00665  * \return              \c 0 on success.
00666  * \return              A specific error code on failure.
00667  */
00668 int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
00669                       unsigned char *tag, size_t tag_len );
00670 
00671 /**
00672  * \brief               This function checks the tag for AEAD ciphers.
00673  *                      Only supported with GCM.
00674  *                      Must be called after mbedtls_cipher_finish().
00675  *
00676  * \param ctx           The generic cipher context.
00677  * \param tag           The buffer holding the tag.
00678  * \param tag_len       The length of the tag to check.
00679  *
00680  * \return              \c 0 on success.
00681  * \return              A specific error code on failure.
00682  */
00683 int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
00684                       const unsigned char *tag, size_t tag_len );
00685 #endif /* MBEDTLS_GCM_C */
00686 
00687 /**
00688  * \brief               The generic all-in-one encryption/decryption function,
00689  *                      for all ciphers except AEAD constructs.
00690  *
00691  * \param ctx           The generic cipher context.
00692  * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
00693  * \param iv_len        The IV length for ciphers with variable-size IV.
00694  *                      This parameter is discarded by ciphers with fixed-size
00695  *                      IV.
00696  * \param input         The buffer holding the input data.
00697  * \param ilen          The length of the input data.
00698  * \param output        The buffer for the output data. Must be able to hold at
00699  *                      least \p ilen + block_size. Must not be the same buffer
00700  *                      as input.
00701  * \param olen          The length of the output data, to be updated with the
00702  *                      actual number of Bytes written.
00703  *
00704  * \note                Some ciphers do not use IVs nor nonce. For these
00705  *                      ciphers, use \p iv = NULL and \p iv_len = 0.
00706  *
00707  * \return              \c 0 on success.
00708  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00709  *                      parameter-verification failure.
00710  * \return              #MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED on decryption
00711  *                      expecting a full block but not receiving one.
00712  * \return              #MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
00713  *                      while decrypting.
00714  * \return              A cipher-specific error code on failure.
00715  */
00716 int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx,
00717                   const unsigned char *iv, size_t iv_len,
00718                   const unsigned char *input, size_t ilen,
00719                   unsigned char *output, size_t *olen );
00720 
00721 #if defined(MBEDTLS_CIPHER_MODE_AEAD)
00722 /**
00723  * \brief               The generic autenticated encryption (AEAD) function.
00724  *
00725  * \param ctx           The generic cipher context.
00726  * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
00727  * \param iv_len        The IV length for ciphers with variable-size IV.
00728  *                      This parameter is discarded by ciphers with fixed-size IV.
00729  * \param ad            The additional data to authenticate.
00730  * \param ad_len        The length of \p ad.
00731  * \param input         The buffer holding the input data.
00732  * \param ilen          The length of the input data.
00733  * \param output        The buffer for the output data.
00734  *                      Must be able to hold at least \p ilen.
00735  * \param olen          The length of the output data, to be updated with the
00736  *                      actual number of Bytes written.
00737  * \param tag           The buffer for the authentication tag.
00738  * \param tag_len       The desired length of the authentication tag.
00739  *
00740  * \return              \c 0 on success.
00741  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00742  *                      parameter-verification failure.
00743  * \return              A cipher-specific error code on failure.
00744  */
00745 int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx,
00746                          const unsigned char *iv, size_t iv_len,
00747                          const unsigned char *ad, size_t ad_len,
00748                          const unsigned char *input, size_t ilen,
00749                          unsigned char *output, size_t *olen,
00750                          unsigned char *tag, size_t tag_len );
00751 
00752 /**
00753  * \brief               The generic autenticated decryption (AEAD) function.
00754  *
00755  * \note                If the data is not authentic, then the output buffer
00756  *                      is zeroed out to prevent the unauthentic plaintext being
00757  *                      used, making this interface safer.
00758  *
00759  * \param ctx           The generic cipher context.
00760  * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
00761  * \param iv_len        The IV length for ciphers with variable-size IV.
00762  *                      This parameter is discarded by ciphers with fixed-size IV.
00763  * \param ad            The additional data to be authenticated.
00764  * \param ad_len        The length of \p ad.
00765  * \param input         The buffer holding the input data.
00766  * \param ilen          The length of the input data.
00767  * \param output        The buffer for the output data.
00768  *                      Must be able to hold at least \p ilen.
00769  * \param olen          The length of the output data, to be updated with the
00770  *                      actual number of Bytes written.
00771  * \param tag           The buffer holding the authentication tag.
00772  * \param tag_len       The length of the authentication tag.
00773  *
00774  * \return              \c 0 on success.
00775  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
00776  *                      parameter-verification failure.
00777  * \return              #MBEDTLS_ERR_CIPHER_AUTH_FAILED if data is not authentic.
00778  * \return              A cipher-specific error code on failure.
00779  */
00780 int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
00781                          const unsigned char *iv, size_t iv_len,
00782                          const unsigned char *ad, size_t ad_len,
00783                          const unsigned char *input, size_t ilen,
00784                          unsigned char *output, size_t *olen,
00785                          const unsigned char *tag, size_t tag_len );
00786 #endif /* MBEDTLS_CIPHER_MODE_AEAD */
00787 
00788 #ifdef __cplusplus
00789 }
00790 #endif
00791 
00792 #endif /* MBEDTLS_CIPHER_H */