include/mbedtls/des.h

/**
 * \file des.h
 *
 * \brief DES block cipher
 *
 * \warning   DES is considered a weak cipher and its use constitutes a
 *            security risk. We recommend considering stronger ciphers
 *            instead.
 */
/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
#ifndef MBEDTLS_DES_H
#define MBEDTLS_DES_H
#include "mbedtls/private_access.h"

#include "mbedtls/build_info.h"

#include <stddef.h>
#include <stdint.h>

#define MBEDTLS_DES_ENCRYPT 1
#define MBEDTLS_DES_DECRYPT 0

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

#define MBEDTLS_DES_KEY_SIZE 8

#ifdef __cplusplus
extern "C" {
#endif

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

/**
 * \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 mbedtls_des_context {
    uint32_t MBEDTLS_PRIVATE(sk)[32]; /*!<  DES subkeys       */
} mbedtls_des_context;

/**
 * \brief          Triple-DES context structure
 */
typedef struct mbedtls_des3_context {
    uint32_t MBEDTLS_PRIVATE(sk)[96]; /*!<  3DES subkeys      */
} mbedtls_des3_context;

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

/**
 * \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 mbedtls_des_init(mbedtls_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 mbedtls_des_free(mbedtls_des_context *ctx);

/**
 * \brief          Initialize Triple-DES context
 *
 * \param ctx      DES3 context to be initialized
 */
void mbedtls_des3_init(mbedtls_des3_context *ctx);

/**
 * \brief          Clear Triple-DES context
 *
 * \param ctx      DES3 context to be cleared
 */
void mbedtls_des3_free(mbedtls_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 mbedtls_des_key_set_parity(unsigned char key[MBEDTLS_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 mbedtls_des_key_check_key_parity(
    const unsigned char key[MBEDTLS_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 mbedtls_des_key_check_weak(const unsigned char key[MBEDTLS_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 mbedtls_des_setkey_enc(mbedtls_des_context *ctx,
                           const unsigned char key[MBEDTLS_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 mbedtls_des_setkey_dec(mbedtls_des_context *ctx,
                           const unsigned char key[MBEDTLS_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 mbedtls_des3_set2key_enc(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_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 mbedtls_des3_set2key_dec(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_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 mbedtls_des3_set3key_enc(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_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 mbedtls_des3_set3key_dec(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_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 mbedtls_des_crypt_ecb(mbedtls_des_context *ctx,
                          const unsigned char input[8],
                          unsigned char output[8]);

#if defined(MBEDTLS_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     MBEDTLS_DES_ENCRYPT or MBEDTLS_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 mbedtls_des_crypt_cbc(mbedtls_des_context *ctx,
                          int mode,
                          size_t length,
                          unsigned char iv[8],
                          const unsigned char *input,
                          unsigned char *output);
#endif /* MBEDTLS_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 mbedtls_des3_crypt_ecb(mbedtls_des3_context *ctx,
                           const unsigned char input[8],
                           unsigned char output[8]);

#if defined(MBEDTLS_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     MBEDTLS_DES_ENCRYPT or MBEDTLS_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 MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH
 */
int mbedtls_des3_crypt_cbc(mbedtls_des3_context *ctx,
                           int mode,
                           size_t length,
                           unsigned char iv[8],
                           const unsigned char *input,
                           unsigned char *output);
#endif /* MBEDTLS_CIPHER_MODE_CBC */

/**
 * \brief          Internal function for key expansion.
 *                 (Only exposed to allow overriding it,
 *                 see MBEDTLS_DES_SETKEY_ALT)
 *
 * \param SK       Round keys
 * \param key      Base key
 *
 * \warning        DES is considered a weak cipher and its use constitutes a
 *                 security risk. We recommend considering stronger ciphers
 *                 instead.
 */
void mbedtls_des_setkey(uint32_t SK[32],
                        const unsigned char key[MBEDTLS_DES_KEY_SIZE]);

#if defined(MBEDTLS_SELF_TEST)

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

#endif /* MBEDTLS_SELF_TEST */

#ifdef __cplusplus
}
#endif

#endif /* des.h */