include/polarssl/des.h

/**
 * \file des.h
 *
 * \brief DES block cipher
 *
 *  Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 *
 *  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.
 *
 * \warning   DES is considered a weak cipher and its use constitutes a
 *            security risk. We recommend considering stronger ciphers instead.
 *
 */
#ifndef POLARSSL_DES_H
#define POLARSSL_DES_H

#if !defined(POLARSSL_CONFIG_FILE)
#include "config.h"
#else
#include POLARSSL_CONFIG_FILE
#endif

#include <stddef.h>

#if defined(_MSC_VER) && !defined(EFIX64) && !defined(EFI32)
#include <basetsd.h>
typedef UINT32 uint32_t;
#else
#include <inttypes.h>
#endif

#define DES_ENCRYPT     1
#define DES_DECRYPT     0

#define POLARSSL_ERR_DES_INVALID_INPUT_LENGTH              -0x0032  /**< The data input has an invalid length. */

#define DES_KEY_SIZE    8

#if !defined(POLARSSL_DES_ALT)
// Regular implementation
//

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          DES context structure
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
typedef struct
{
    int mode;                   /*!<  encrypt/decrypt   */
    uint32_t sk[32];            /*!<  DES subkeys       */
}
des_context;

/**
 * \brief          Triple-DES context structure
 */
typedef struct
{
    int mode;                   /*!<  encrypt/decrypt   */
    uint32_t sk[96];            /*!<  3DES subkeys      */
}
des3_context;

/**
 * \brief          Initialize DES context
 *
 * \param ctx      DES context to be initialized
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
void des_init( des_context *ctx );

/**
 * \brief          Clear DES context
 *
 * \param ctx      DES context to be cleared
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
void des_free( des_context *ctx );

/**
 * \brief          Initialize Triple-DES context
 *
 * \param ctx      DES3 context to be initialized
 */
void des3_init( des3_context *ctx );

/**
 * \brief          Clear Triple-DES context
 *
 * \param ctx      DES3 context to be cleared
 */
void des3_free( des3_context *ctx );

/**
 * \brief          Set key parity on the given key to odd.
 *
 *                 DES keys are 56 bits long, but each byte is padded with
 *                 a parity bit to allow verification.
 *
 * \param key      8-byte secret key
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
void des_key_set_parity( unsigned char key[DES_KEY_SIZE] );

/**
 * \brief          Check that key parity on the given key is odd.
 *
 *                 DES keys are 56 bits long, but each byte is padded with
 *                 a parity bit to allow verification.
 *
 * \param key      8-byte secret key
 *
 * \return         0 is parity was ok, 1 if parity was not correct.
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
int des_key_check_key_parity( const unsigned char key[DES_KEY_SIZE] );

/**
 * \brief          Check that key is not a weak or semi-weak DES key
 *
 * \param key      8-byte secret key
 *
 * \return         0 if no weak key was found, 1 if a weak key was identified.
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
int des_key_check_weak( const unsigned char key[DES_KEY_SIZE] );

/**
 * \brief          DES key schedule (56-bit, encryption)
 *
 * \param ctx      DES context to be initialized
 * \param key      8-byte secret key
 *
 * \return         0
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
int des_setkey_enc( des_context *ctx, const unsigned char key[DES_KEY_SIZE] );

/**
 * \brief          DES key schedule (56-bit, decryption)
 *
 * \param ctx      DES context to be initialized
 * \param key      8-byte secret key
 *
 * \return         0
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
int des_setkey_dec( des_context *ctx, const unsigned char key[DES_KEY_SIZE] );

/**
 * \brief          Triple-DES key schedule (112-bit, encryption)
 *
 * \param ctx      3DES context to be initialized
 * \param key      16-byte secret key
 *
 * \return         0
 */
int des3_set2key_enc( des3_context *ctx,
                      const unsigned char key[DES_KEY_SIZE * 2] );

/**
 * \brief          Triple-DES key schedule (112-bit, decryption)
 *
 * \param ctx      3DES context to be initialized
 * \param key      16-byte secret key
 *
 * \return         0
 */
int des3_set2key_dec( des3_context *ctx,
                      const unsigned char key[DES_KEY_SIZE * 2] );

/**
 * \brief          Triple-DES key schedule (168-bit, encryption)
 *
 * \param ctx      3DES context to be initialized
 * \param key      24-byte secret key
 *
 * \return         0
 */
int des3_set3key_enc( des3_context *ctx,
                      const unsigned char key[DES_KEY_SIZE * 3] );

/**
 * \brief          Triple-DES key schedule (168-bit, decryption)
 *
 * \param ctx      3DES context to be initialized
 * \param key      24-byte secret key
 *
 * \return         0
 */
int des3_set3key_dec( des3_context *ctx,
                      const unsigned char key[DES_KEY_SIZE * 3] );

/**
 * \brief          DES-ECB block encryption/decryption
 *
 * \param ctx      DES context
 * \param input    64-bit input block
 * \param output   64-bit output block
 *
 * \return         0 if successful
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
int des_crypt_ecb( des_context *ctx,
                    const unsigned char input[8],
                    unsigned char output[8] );

#if defined(POLARSSL_CIPHER_MODE_CBC)
/**
 * \brief          DES-CBC buffer encryption/decryption
 *
 * \note           Upon exit, the content of the IV is updated so that you can
 *                 call the function same function again on the following
 *                 block(s) of data and get the same result as if it was
 *                 encrypted in one call. This allows a "streaming" usage.
 *                 If on the other hand you need to retain the contents of the
 *                 IV, you should either save it manually or use the cipher
 *                 module instead.
 *
 * \param ctx      DES context
 * \param mode     DES_ENCRYPT or DES_DECRYPT
 * \param length   length of the input data
 * \param iv       initialization vector (updated after use)
 * \param input    buffer holding the input data
 * \param output   buffer holding the output data
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
int des_crypt_cbc( des_context *ctx,
                    int mode,
                    size_t length,
                    unsigned char iv[8],
                    const unsigned char *input,
                    unsigned char *output );
#endif /* POLARSSL_CIPHER_MODE_CBC */

/**
 * \brief          3DES-ECB block encryption/decryption
 *
 * \param ctx      3DES context
 * \param input    64-bit input block
 * \param output   64-bit output block
 *
 * \return         0 if successful
 */
int des3_crypt_ecb( des3_context *ctx,
                     const unsigned char input[8],
                     unsigned char output[8] );

#if defined(POLARSSL_CIPHER_MODE_CBC)
/**
 * \brief          3DES-CBC buffer encryption/decryption
 *
 * \note           Upon exit, the content of the IV is updated so that you can
 *                 call the function same function again on the following
 *                 block(s) of data and get the same result as if it was
 *                 encrypted in one call. This allows a "streaming" usage.
 *                 If on the other hand you need to retain the contents of the
 *                 IV, you should either save it manually or use the cipher
 *                 module instead.
 *
 * \param ctx      3DES context
 * \param mode     DES_ENCRYPT or DES_DECRYPT
 * \param length   length of the input data
 * \param iv       initialization vector (updated after use)
 * \param input    buffer holding the input data
 * \param output   buffer holding the output data
 *
 * \return         0 if successful, or POLARSSL_ERR_DES_INVALID_INPUT_LENGTH
 */
int des3_crypt_cbc( des3_context *ctx,
                     int mode,
                     size_t length,
                     unsigned char iv[8],
                     const unsigned char *input,
                     unsigned char *output );
#endif /* POLARSSL_CIPHER_MODE_CBC */

#ifdef __cplusplus
}
#endif

#else  /* POLARSSL_DES_ALT */
#include "des_alt.h"
#endif /* POLARSSL_DES_ALT */

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          Checkup routine
 *
 * \return         0 if successful, or 1 if the test failed
 */
int des_self_test( int verbose );

#ifdef __cplusplus
}
#endif

#endif /* des.h */