/** * \file cipher.h * * \brief Generic cipher wrapper. * * \author Adriaan de Jong * * Copyright (C) 2006-2010, Brainspark B.V. * * This file is part of PolarSSL (http://www.polarssl.org) * Lead Maintainer: Paul Bakker * * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #ifndef POLARSSL_CIPHER_H #define POLARSSL_CIPHER_H #include typedef enum { POLARSSL_CIPHER_ID_NONE = 0, POLARSSL_CIPHER_ID_AES, POLARSSL_CIPHER_ID_DES, POLARSSL_CIPHER_ID_3DES, POLARSSL_CIPHER_ID_CAMELLIA, } cipher_id_t; typedef enum { POLARSSL_CIPHER_NONE = 0, POLARSSL_CIPHER_CAMELLIA_128_CBC, POLARSSL_CIPHER_CAMELLIA_192_CBC, POLARSSL_CIPHER_CAMELLIA_256_CBC, POLARSSL_CIPHER_AES_128_CBC, POLARSSL_CIPHER_AES_192_CBC, POLARSSL_CIPHER_AES_256_CBC, POLARSSL_CIPHER_DES_CBC, POLARSSL_CIPHER_DES_EDE_CBC, POLARSSL_CIPHER_DES_EDE3_CBC } cipher_type_t; typedef enum { POLARSSL_MODE_NONE = 0, POLARSSL_MODE_CBC, POLARSSL_MODE_CFB, POLARSSL_MODE_OFB, } cipher_mode_t; typedef enum { POLARSSL_DECRYPT = 0, POLARSSL_ENCRYPT, } operation_t; enum { /** Undefined key length */ POLARSSL_KEY_LENGTH_NONE = 0, /** Key length, in bits, for DES keys */ POLARSSL_KEY_LENGTH_DES = 56, /** Key length, in bits, for DES in two key EDE */ POLARSSL_KEY_LENGTH_DES_EDE = 112, /** Key length, in bits, for DES in three-key EDE */ POLARSSL_KEY_LENGTH_DES_EDE3 = 168, /** Maximum length of any IV, in bytes */ POLARSSL_MAX_IV_LENGTH = 16, }; /** * Cipher information. Allows cipher functions to be called in a generic way. */ typedef struct { /** Full cipher identifier (e.g. POLARSSL_CIPHER_AES_256_CBC) */ cipher_type_t type; /** Base Cipher type (e.g. POLARSSL_CIPHER_ID_AES) */ cipher_id_t cipher; /** Cipher mode (e.g. POLARSSL_CIPHER_MODE_CBC) */ cipher_mode_t mode; /** Cipher key length, in bits (default length for variable sized ciphers) */ int key_length; /** Name of the message digest */ const char * name; /** IV size, in bytes */ int iv_size; /** block size, in bytes */ int block_size; /** Encrypt using CBC */ int (*cbc_func)( void *ctx, operation_t mode, int length, unsigned char *iv, const unsigned char *input, unsigned char *output ); /** Set key for encryption purposes */ int (*setkey_enc_func)( void *ctx, const unsigned char *key, int key_length); /** Set key for decryption purposes */ int (*setkey_dec_func)( void *ctx, const unsigned char *key, int key_length); /** Allocate a new context */ void * (*ctx_alloc_func)( void ); /** Free the given context */ void (*ctx_free_func)( void *ctx ); } cipher_info_t; /** * Generic message digest context. */ typedef struct { /** Information about the associated cipher */ const cipher_info_t *cipher_info; /** Key length to use */ int key_length; /** Operation that the context's key has been initialised for */ operation_t operation; /** Buffer for data that hasn't been encrypted yet */ unsigned char unprocessed_data[POLARSSL_MAX_IV_LENGTH]; /** Number of bytes that still need processing */ int unprocessed_len; /** Current IV */ unsigned char iv[POLARSSL_MAX_IV_LENGTH]; /** Cipher-specific context */ void *cipher_ctx; } cipher_context_t; #ifdef __cplusplus extern "C" { #endif /** * \brief Returns the list of ciphers supported by the generic cipher module. * * \return a statically allocated array of ciphers, the last entry * is 0. */ const int *cipher_list( void ); /** * \brief Returns the cipher information structure associated * with the given cipher name. * * \param cipher_name Name of the cipher to search for. * * \return the cipher information structure associated with the * given cipher_name, or NULL if not found. */ const cipher_info_t *cipher_info_from_string( const char *cipher_name ); /** * \brief Returns the cipher information structure associated * with the given cipher type. * * \param cipher_type Type of the cipher to search for. * * \return the cipher information structure associated with the * given cipher_type, or NULL if not found. */ const cipher_info_t *cipher_info_from_type( const cipher_type_t cipher_type ); /** * \brief Initialises and fills the cipher context structure with * the appropriate values. * * \param ctx context to initialise. May not be NULL. * \param cipher_info cipher to use. * * \return \c 0 on success, \c 1 on parameter failure, \c 2 if * allocation of the cipher-specific context failed. */ int cipher_init_ctx( cipher_context_t *ctx, const cipher_info_t *cipher_info ); /** * \brief Free the cipher-specific context of ctx. Freeing ctx * itself remains the responsibility of the caller. * * \param ctx Free the cipher-specific context * * \returns 0 on success, 1 if parameter verification fails. */ int cipher_free_ctx( cipher_context_t *ctx ); /** * \brief Returns the block size of the given cipher. * * \param ctx cipher's context. Must have been initialised. * * \return size of the cipher's blocks, or 0 if ctx has not been * initialised. */ static inline int cipher_get_block_size( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; return ctx->cipher_info->block_size; } /** * \brief Returns the size of the cipher's IV. * * \param ctx cipher's context. Must have been initialised. * * \return size of the cipher's IV, or 0 if ctx has not been * initialised. */ static inline int cipher_get_iv_size( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; return ctx->cipher_info->iv_size; } /** * \brief Returns the type of the given cipher. * * \param ctx cipher's context. Must have been initialised. * * \return type of the cipher, or POLARSSL_CIPHER_NONE if ctx has * not been initialised. */ static inline cipher_type_t cipher_get_type( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; return ctx->cipher_info->type; } /** * \brief Returns the name of the given cipher, as a string. * * \param ctx cipher's context. Must have been initialised. * * \return name of the cipher, or NULL if ctx was not initialised. */ static inline const char *cipher_get_name( const cipher_context_t *ctx ) { if( NULL == ctx || NULL == ctx->cipher_info ) return 0; return ctx->cipher_info->name; } /** * \brief Returns the key length of the cipher. * * \param ctx cipher's context. Must have been initialised. * * \return cipher's key length, in bits, or * POLARSSL_KEY_LENGTH_NONE if ctx has not been * initialised. */ static inline int cipher_get_key_size ( const cipher_context_t *ctx ) { if( NULL == ctx ) return POLARSSL_KEY_LENGTH_NONE; return ctx->key_length; } /** * \brief Set the key to use with the given context. * * \param ctx generic cipher context. May not be NULL. Must have been * initialised using cipher_context_from_type or * cipher_context_from_string. * \param key The key to use. * \param key_length key length to use, in bits. * \param operation Operation that the key will be used for, either * POLARSSL_ENCRYPT or POLARSSL_DECRYPT. * * \returns 0 on success, 1 if parameter verification fails. */ int cipher_setkey( cipher_context_t *ctx, const unsigned char *key, int key_length, const operation_t operation ); /** * \brief Reset the given context, setting the IV to iv * * \param ctx generic cipher context * \param iv IV to use * * \returns 0 on success, 1 if parameter verification fails. */ int cipher_reset( cipher_context_t *ctx, const unsigned char *iv ); /** * \brief Generic cipher update function. Encrypts/decrypts * using the given cipher context. Writes as many block * size'd blocks of data as possible to output. Any data * that cannot be written immediately will either be added * to the next block, or flushed when cipher_final is * called. * * \param ctx generic cipher context * \param input buffer holding the input data * \param ilen length of the input data * \param output buffer for the output data. Should be able to hold at * least ilen + block_size. Cannot be the same buffer as * input! * \param olen length of the output data, will be filled with the * actual number of bytes written. * * \returns 0 on success, 1 if parameter verification fails. */ int cipher_update( cipher_context_t *ctx, const unsigned char *input, int ilen, unsigned char *output, int *olen ); /** * \brief Generic cipher finalisation function. If data still * needs to be flushed from an incomplete block, data * contained within it will be padded with the size of * the last block, and written to the output buffer. * * \param ctx Generic message digest context * \param output buffer to write data to. Needs block_size data available. * \param olen length of the data written to the output buffer. * * \returns 0 on success, 1 if parameter verification fails. */ int cipher_finish( cipher_context_t *ctx, unsigned char *output, int *olen); /** * \brief Checkup routine * * \return 0 if successful, or 1 if the test failed */ int cipher_self_test( int verbose ); #ifdef __cplusplus } #endif #endif /* POLARSSL_MD_H */