library/des.c

/*
 *  FIPS-46-3 compliant Triple-DES implementation
 *
 *  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.
 */
/*
 *  DES, on which TDES is based, was originally designed by Horst Feistel
 *  at IBM in 1974, and was adopted as a standard by NIST (formerly NBS).
 *
 *  http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf
 */

#include "common.h"

#if defined(MBEDTLS_DES_C)

#include "mbedtls/des.h"
#include "mbedtls/error.h"
#include "mbedtls/platform_util.h"

#include <string.h>

#include "mbedtls/platform.h"

#if !defined(MBEDTLS_DES_ALT)

/*
 * Expanded DES S-boxes
 */
static const uint32_t SB1[64] =
{
    0x01010400, 0x00000000, 0x00010000, 0x01010404,
    0x01010004, 0x00010404, 0x00000004, 0x00010000,
    0x00000400, 0x01010400, 0x01010404, 0x00000400,
    0x01000404, 0x01010004, 0x01000000, 0x00000004,
    0x00000404, 0x01000400, 0x01000400, 0x00010400,
    0x00010400, 0x01010000, 0x01010000, 0x01000404,
    0x00010004, 0x01000004, 0x01000004, 0x00010004,
    0x00000000, 0x00000404, 0x00010404, 0x01000000,
    0x00010000, 0x01010404, 0x00000004, 0x01010000,
    0x01010400, 0x01000000, 0x01000000, 0x00000400,
    0x01010004, 0x00010000, 0x00010400, 0x01000004,
    0x00000400, 0x00000004, 0x01000404, 0x00010404,
    0x01010404, 0x00010004, 0x01010000, 0x01000404,
    0x01000004, 0x00000404, 0x00010404, 0x01010400,
    0x00000404, 0x01000400, 0x01000400, 0x00000000,
    0x00010004, 0x00010400, 0x00000000, 0x01010004
};

static const uint32_t SB2[64] =
{
    0x80108020, 0x80008000, 0x00008000, 0x00108020,
    0x00100000, 0x00000020, 0x80100020, 0x80008020,
    0x80000020, 0x80108020, 0x80108000, 0x80000000,
    0x80008000, 0x00100000, 0x00000020, 0x80100020,
    0x00108000, 0x00100020, 0x80008020, 0x00000000,
    0x80000000, 0x00008000, 0x00108020, 0x80100000,
    0x00100020, 0x80000020, 0x00000000, 0x00108000,
    0x00008020, 0x80108000, 0x80100000, 0x00008020,
    0x00000000, 0x00108020, 0x80100020, 0x00100000,
    0x80008020, 0x80100000, 0x80108000, 0x00008000,
    0x80100000, 0x80008000, 0x00000020, 0x80108020,
    0x00108020, 0x00000020, 0x00008000, 0x80000000,
    0x00008020, 0x80108000, 0x00100000, 0x80000020,
    0x00100020, 0x80008020, 0x80000020, 0x00100020,
    0x00108000, 0x00000000, 0x80008000, 0x00008020,
    0x80000000, 0x80100020, 0x80108020, 0x00108000
};

static const uint32_t SB3[64] =
{
    0x00000208, 0x08020200, 0x00000000, 0x08020008,
    0x08000200, 0x00000000, 0x00020208, 0x08000200,
    0x00020008, 0x08000008, 0x08000008, 0x00020000,
    0x08020208, 0x00020008, 0x08020000, 0x00000208,
    0x08000000, 0x00000008, 0x08020200, 0x00000200,
    0x00020200, 0x08020000, 0x08020008, 0x00020208,
    0x08000208, 0x00020200, 0x00020000, 0x08000208,
    0x00000008, 0x08020208, 0x00000200, 0x08000000,
    0x08020200, 0x08000000, 0x00020008, 0x00000208,
    0x00020000, 0x08020200, 0x08000200, 0x00000000,
    0x00000200, 0x00020008, 0x08020208, 0x08000200,
    0x08000008, 0x00000200, 0x00000000, 0x08020008,
    0x08000208, 0x00020000, 0x08000000, 0x08020208,
    0x00000008, 0x00020208, 0x00020200, 0x08000008,
    0x08020000, 0x08000208, 0x00000208, 0x08020000,
    0x00020208, 0x00000008, 0x08020008, 0x00020200
};

static const uint32_t SB4[64] =
{
    0x00802001, 0x00002081, 0x00002081, 0x00000080,
    0x00802080, 0x00800081, 0x00800001, 0x00002001,
    0x00000000, 0x00802000, 0x00802000, 0x00802081,
    0x00000081, 0x00000000, 0x00800080, 0x00800001,
    0x00000001, 0x00002000, 0x00800000, 0x00802001,
    0x00000080, 0x00800000, 0x00002001, 0x00002080,
    0x00800081, 0x00000001, 0x00002080, 0x00800080,
    0x00002000, 0x00802080, 0x00802081, 0x00000081,
    0x00800080, 0x00800001, 0x00802000, 0x00802081,
    0x00000081, 0x00000000, 0x00000000, 0x00802000,
    0x00002080, 0x00800080, 0x00800081, 0x00000001,
    0x00802001, 0x00002081, 0x00002081, 0x00000080,
    0x00802081, 0x00000081, 0x00000001, 0x00002000,
    0x00800001, 0x00002001, 0x00802080, 0x00800081,
    0x00002001, 0x00002080, 0x00800000, 0x00802001,
    0x00000080, 0x00800000, 0x00002000, 0x00802080
};

static const uint32_t SB5[64] =
{
    0x00000100, 0x02080100, 0x02080000, 0x42000100,
    0x00080000, 0x00000100, 0x40000000, 0x02080000,
    0x40080100, 0x00080000, 0x02000100, 0x40080100,
    0x42000100, 0x42080000, 0x00080100, 0x40000000,
    0x02000000, 0x40080000, 0x40080000, 0x00000000,
    0x40000100, 0x42080100, 0x42080100, 0x02000100,
    0x42080000, 0x40000100, 0x00000000, 0x42000000,
    0x02080100, 0x02000000, 0x42000000, 0x00080100,
    0x00080000, 0x42000100, 0x00000100, 0x02000000,
    0x40000000, 0x02080000, 0x42000100, 0x40080100,
    0x02000100, 0x40000000, 0x42080000, 0x02080100,
    0x40080100, 0x00000100, 0x02000000, 0x42080000,
    0x42080100, 0x00080100, 0x42000000, 0x42080100,
    0x02080000, 0x00000000, 0x40080000, 0x42000000,
    0x00080100, 0x02000100, 0x40000100, 0x00080000,
    0x00000000, 0x40080000, 0x02080100, 0x40000100
};

static const uint32_t SB6[64] =
{
    0x20000010, 0x20400000, 0x00004000, 0x20404010,
    0x20400000, 0x00000010, 0x20404010, 0x00400000,
    0x20004000, 0x00404010, 0x00400000, 0x20000010,
    0x00400010, 0x20004000, 0x20000000, 0x00004010,
    0x00000000, 0x00400010, 0x20004010, 0x00004000,
    0x00404000, 0x20004010, 0x00000010, 0x20400010,
    0x20400010, 0x00000000, 0x00404010, 0x20404000,
    0x00004010, 0x00404000, 0x20404000, 0x20000000,
    0x20004000, 0x00000010, 0x20400010, 0x00404000,
    0x20404010, 0x00400000, 0x00004010, 0x20000010,
    0x00400000, 0x20004000, 0x20000000, 0x00004010,
    0x20000010, 0x20404010, 0x00404000, 0x20400000,
    0x00404010, 0x20404000, 0x00000000, 0x20400010,
    0x00000010, 0x00004000, 0x20400000, 0x00404010,
    0x00004000, 0x00400010, 0x20004010, 0x00000000,
    0x20404000, 0x20000000, 0x00400010, 0x20004010
};

static const uint32_t SB7[64] =
{
    0x00200000, 0x04200002, 0x04000802, 0x00000000,
    0x00000800, 0x04000802, 0x00200802, 0x04200800,
    0x04200802, 0x00200000, 0x00000000, 0x04000002,
    0x00000002, 0x04000000, 0x04200002, 0x00000802,
    0x04000800, 0x00200802, 0x00200002, 0x04000800,
    0x04000002, 0x04200000, 0x04200800, 0x00200002,
    0x04200000, 0x00000800, 0x00000802, 0x04200802,
    0x00200800, 0x00000002, 0x04000000, 0x00200800,
    0x04000000, 0x00200800, 0x00200000, 0x04000802,
    0x04000802, 0x04200002, 0x04200002, 0x00000002,
    0x00200002, 0x04000000, 0x04000800, 0x00200000,
    0x04200800, 0x00000802, 0x00200802, 0x04200800,
    0x00000802, 0x04000002, 0x04200802, 0x04200000,
    0x00200800, 0x00000000, 0x00000002, 0x04200802,
    0x00000000, 0x00200802, 0x04200000, 0x00000800,
    0x04000002, 0x04000800, 0x00000800, 0x00200002
};

static const uint32_t SB8[64] =
{
    0x10001040, 0x00001000, 0x00040000, 0x10041040,
    0x10000000, 0x10001040, 0x00000040, 0x10000000,
    0x00040040, 0x10040000, 0x10041040, 0x00041000,
    0x10041000, 0x00041040, 0x00001000, 0x00000040,
    0x10040000, 0x10000040, 0x10001000, 0x00001040,
    0x00041000, 0x00040040, 0x10040040, 0x10041000,
    0x00001040, 0x00000000, 0x00000000, 0x10040040,
    0x10000040, 0x10001000, 0x00041040, 0x00040000,
    0x00041040, 0x00040000, 0x10041000, 0x00001000,
    0x00000040, 0x10040040, 0x00001000, 0x00041040,
    0x10001000, 0x00000040, 0x10000040, 0x10040000,
    0x10040040, 0x10000000, 0x00040000, 0x10001040,
    0x00000000, 0x10041040, 0x00040040, 0x10000040,
    0x10040000, 0x10001000, 0x10001040, 0x00000000,
    0x10041040, 0x00041000, 0x00041000, 0x00001040,
    0x00001040, 0x00040040, 0x10000000, 0x10041000
};

/*
 * PC1: left and right halves bit-swap
 */
static const uint32_t LHs[16] =
{
    0x00000000, 0x00000001, 0x00000100, 0x00000101,
    0x00010000, 0x00010001, 0x00010100, 0x00010101,
    0x01000000, 0x01000001, 0x01000100, 0x01000101,
    0x01010000, 0x01010001, 0x01010100, 0x01010101
};

static const uint32_t RHs[16] =
{
    0x00000000, 0x01000000, 0x00010000, 0x01010000,
    0x00000100, 0x01000100, 0x00010100, 0x01010100,
    0x00000001, 0x01000001, 0x00010001, 0x01010001,
    0x00000101, 0x01000101, 0x00010101, 0x01010101,
};

/*
 * Initial Permutation macro
 */
#define DES_IP(X, Y)                                                       \
    do                                                                    \
    {                                                                     \
        T = (((X) >>  4) ^ (Y)) & 0x0F0F0F0F; (Y) ^= T; (X) ^= (T <<  4); \
        T = (((X) >> 16) ^ (Y)) & 0x0000FFFF; (Y) ^= T; (X) ^= (T << 16); \
        T = (((Y) >>  2) ^ (X)) & 0x33333333; (X) ^= T; (Y) ^= (T <<  2); \
        T = (((Y) >>  8) ^ (X)) & 0x00FF00FF; (X) ^= T; (Y) ^= (T <<  8); \
        (Y) = (((Y) << 1) | ((Y) >> 31)) & 0xFFFFFFFF;                    \
        T = ((X) ^ (Y)) & 0xAAAAAAAA; (Y) ^= T; (X) ^= T;                 \
        (X) = (((X) << 1) | ((X) >> 31)) & 0xFFFFFFFF;                    \
    } while (0)

/*
 * Final Permutation macro
 */
#define DES_FP(X, Y)                                                       \
    do                                                                    \
    {                                                                     \
        (X) = (((X) << 31) | ((X) >> 1)) & 0xFFFFFFFF;                    \
        T = ((X) ^ (Y)) & 0xAAAAAAAA; (X) ^= T; (Y) ^= T;                 \
        (Y) = (((Y) << 31) | ((Y) >> 1)) & 0xFFFFFFFF;                    \
        T = (((Y) >>  8) ^ (X)) & 0x00FF00FF; (X) ^= T; (Y) ^= (T <<  8); \
        T = (((Y) >>  2) ^ (X)) & 0x33333333; (X) ^= T; (Y) ^= (T <<  2); \
        T = (((X) >> 16) ^ (Y)) & 0x0000FFFF; (Y) ^= T; (X) ^= (T << 16); \
        T = (((X) >>  4) ^ (Y)) & 0x0F0F0F0F; (Y) ^= T; (X) ^= (T <<  4); \
    } while (0)

/*
 * DES round macro
 */
#define DES_ROUND(X, Y)                              \
    do                                              \
    {                                               \
        T = *SK++ ^ (X);                            \
        (Y) ^= SB8[(T) & 0x3F] ^            \
               SB6[(T >>  8) & 0x3F] ^            \
               SB4[(T >> 16) & 0x3F] ^            \
               SB2[(T >> 24) & 0x3F];             \
                                                    \
        T = *SK++ ^ (((X) << 28) | ((X) >> 4));     \
        (Y) ^= SB7[(T) & 0x3F] ^            \
               SB5[(T >>  8) & 0x3F] ^            \
               SB3[(T >> 16) & 0x3F] ^            \
               SB1[(T >> 24) & 0x3F];             \
    } while (0)

#define SWAP(a, b)                                       \
    do                                                  \
    {                                                   \
        uint32_t t = (a); (a) = (b); (b) = t; t = 0;    \
    } while (0)

void mbedtls_des_init(mbedtls_des_context *ctx)
{
    memset(ctx, 0, sizeof(mbedtls_des_context));
}

void mbedtls_des_free(mbedtls_des_context *ctx)
{
    if (ctx == NULL) {
        return;
    }

    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_des_context));
}

void mbedtls_des3_init(mbedtls_des3_context *ctx)
{
    memset(ctx, 0, sizeof(mbedtls_des3_context));
}

void mbedtls_des3_free(mbedtls_des3_context *ctx)
{
    if (ctx == NULL) {
        return;
    }

    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_des3_context));
}

static const unsigned char odd_parity_table[128] = { 1,  2,  4,  7,  8,
                                                     11, 13, 14, 16, 19, 21, 22, 25, 26, 28, 31, 32,
                                                     35, 37, 38, 41, 42, 44,
                                                     47, 49, 50, 52, 55, 56, 59, 61, 62, 64, 67, 69,
                                                     70, 73, 74, 76, 79, 81,
                                                     82, 84, 87, 88, 91, 93, 94, 97, 98, 100, 103,
                                                     104, 107, 109, 110, 112,
                                                     115, 117, 118, 121, 122, 124, 127, 128, 131,
                                                     133, 134, 137, 138, 140,
                                                     143, 145, 146, 148, 151, 152, 155, 157, 158,
                                                     161, 162, 164, 167, 168,
                                                     171, 173, 174, 176, 179, 181, 182, 185, 186,
                                                     188, 191, 193, 194, 196,
                                                     199, 200, 203, 205, 206, 208, 211, 213, 214,
                                                     217, 218, 220, 223, 224,
                                                     227, 229, 230, 233, 234, 236, 239, 241, 242,
                                                     244, 247, 248, 251, 253,
                                                     254 };

void mbedtls_des_key_set_parity(unsigned char key[MBEDTLS_DES_KEY_SIZE])
{
    int i;

    for (i = 0; i < MBEDTLS_DES_KEY_SIZE; i++) {
        key[i] = odd_parity_table[key[i] / 2];
    }
}

/*
 * Check the given key's parity, returns 1 on failure, 0 on SUCCESS
 */
int mbedtls_des_key_check_key_parity(const unsigned char key[MBEDTLS_DES_KEY_SIZE])
{
    int i;

    for (i = 0; i < MBEDTLS_DES_KEY_SIZE; i++) {
        if (key[i] != odd_parity_table[key[i] / 2]) {
            return 1;
        }
    }

    return 0;
}

/*
 * Table of weak and semi-weak keys
 *
 * Source: http://en.wikipedia.org/wiki/Weak_key
 *
 * Weak:
 * Alternating ones + zeros (0x0101010101010101)
 * Alternating 'F' + 'E' (0xFEFEFEFEFEFEFEFE)
 * '0xE0E0E0E0F1F1F1F1'
 * '0x1F1F1F1F0E0E0E0E'
 *
 * Semi-weak:
 * 0x011F011F010E010E and 0x1F011F010E010E01
 * 0x01E001E001F101F1 and 0xE001E001F101F101
 * 0x01FE01FE01FE01FE and 0xFE01FE01FE01FE01
 * 0x1FE01FE00EF10EF1 and 0xE01FE01FF10EF10E
 * 0x1FFE1FFE0EFE0EFE and 0xFE1FFE1FFE0EFE0E
 * 0xE0FEE0FEF1FEF1FE and 0xFEE0FEE0FEF1FEF1
 *
 */

#define WEAK_KEY_COUNT 16

static const unsigned char weak_key_table[WEAK_KEY_COUNT][MBEDTLS_DES_KEY_SIZE] =
{
    { 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01 },
    { 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE },
    { 0x1F, 0x1F, 0x1F, 0x1F, 0x0E, 0x0E, 0x0E, 0x0E },
    { 0xE0, 0xE0, 0xE0, 0xE0, 0xF1, 0xF1, 0xF1, 0xF1 },

    { 0x01, 0x1F, 0x01, 0x1F, 0x01, 0x0E, 0x01, 0x0E },
    { 0x1F, 0x01, 0x1F, 0x01, 0x0E, 0x01, 0x0E, 0x01 },
    { 0x01, 0xE0, 0x01, 0xE0, 0x01, 0xF1, 0x01, 0xF1 },
    { 0xE0, 0x01, 0xE0, 0x01, 0xF1, 0x01, 0xF1, 0x01 },
    { 0x01, 0xFE, 0x01, 0xFE, 0x01, 0xFE, 0x01, 0xFE },
    { 0xFE, 0x01, 0xFE, 0x01, 0xFE, 0x01, 0xFE, 0x01 },
    { 0x1F, 0xE0, 0x1F, 0xE0, 0x0E, 0xF1, 0x0E, 0xF1 },
    { 0xE0, 0x1F, 0xE0, 0x1F, 0xF1, 0x0E, 0xF1, 0x0E },
    { 0x1F, 0xFE, 0x1F, 0xFE, 0x0E, 0xFE, 0x0E, 0xFE },
    { 0xFE, 0x1F, 0xFE, 0x1F, 0xFE, 0x0E, 0xFE, 0x0E },
    { 0xE0, 0xFE, 0xE0, 0xFE, 0xF1, 0xFE, 0xF1, 0xFE },
    { 0xFE, 0xE0, 0xFE, 0xE0, 0xFE, 0xF1, 0xFE, 0xF1 }
};

int mbedtls_des_key_check_weak(const unsigned char key[MBEDTLS_DES_KEY_SIZE])
{
    int i;

    for (i = 0; i < WEAK_KEY_COUNT; i++) {
        if (memcmp(weak_key_table[i], key, MBEDTLS_DES_KEY_SIZE) == 0) {
            return 1;
        }
    }

    return 0;
}

#if !defined(MBEDTLS_DES_SETKEY_ALT)
void mbedtls_des_setkey(uint32_t SK[32], const unsigned char key[MBEDTLS_DES_KEY_SIZE])
{
    int i;
    uint32_t X, Y, T;

    X = MBEDTLS_GET_UINT32_BE(key, 0);
    Y = MBEDTLS_GET_UINT32_BE(key, 4);

    /*
     * Permuted Choice 1
     */
    T =  ((Y >>  4) ^ X) & 0x0F0F0F0F;  X ^= T; Y ^= (T <<  4);
    T =  ((Y) ^ X) & 0x10101010;  X ^= T; Y ^= (T);

    X =   (LHs[(X) & 0xF] << 3) | (LHs[(X >>  8) & 0xF] << 2)
        | (LHs[(X >> 16) & 0xF] << 1) | (LHs[(X >> 24) & 0xF])
        | (LHs[(X >>  5) & 0xF] << 7) | (LHs[(X >> 13) & 0xF] << 6)
        | (LHs[(X >> 21) & 0xF] << 5) | (LHs[(X >> 29) & 0xF] << 4);

    Y =   (RHs[(Y >>  1) & 0xF] << 3) | (RHs[(Y >>  9) & 0xF] << 2)
        | (RHs[(Y >> 17) & 0xF] << 1) | (RHs[(Y >> 25) & 0xF])
        | (RHs[(Y >>  4) & 0xF] << 7) | (RHs[(Y >> 12) & 0xF] << 6)
        | (RHs[(Y >> 20) & 0xF] << 5) | (RHs[(Y >> 28) & 0xF] << 4);

    X &= 0x0FFFFFFF;
    Y &= 0x0FFFFFFF;

    /*
     * calculate subkeys
     */
    for (i = 0; i < 16; i++) {
        if (i < 2 || i == 8 || i == 15) {
            X = ((X <<  1) | (X >> 27)) & 0x0FFFFFFF;
            Y = ((Y <<  1) | (Y >> 27)) & 0x0FFFFFFF;
        } else {
            X = ((X <<  2) | (X >> 26)) & 0x0FFFFFFF;
            Y = ((Y <<  2) | (Y >> 26)) & 0x0FFFFFFF;
        }

        *SK++ =   ((X <<  4) & 0x24000000) | ((X << 28) & 0x10000000)
                | ((X << 14) & 0x08000000) | ((X << 18) & 0x02080000)
                | ((X <<  6) & 0x01000000) | ((X <<  9) & 0x00200000)
                | ((X >>  1) & 0x00100000) | ((X << 10) & 0x00040000)
                | ((X <<  2) & 0x00020000) | ((X >> 10) & 0x00010000)
                | ((Y >> 13) & 0x00002000) | ((Y >>  4) & 0x00001000)
                | ((Y <<  6) & 0x00000800) | ((Y >>  1) & 0x00000400)
                | ((Y >> 14) & 0x00000200) | ((Y) & 0x00000100)
                | ((Y >>  5) & 0x00000020) | ((Y >> 10) & 0x00000010)
                | ((Y >>  3) & 0x00000008) | ((Y >> 18) & 0x00000004)
                | ((Y >> 26) & 0x00000002) | ((Y >> 24) & 0x00000001);

        *SK++ =   ((X << 15) & 0x20000000) | ((X << 17) & 0x10000000)
                | ((X << 10) & 0x08000000) | ((X << 22) & 0x04000000)
                | ((X >>  2) & 0x02000000) | ((X <<  1) & 0x01000000)
                | ((X << 16) & 0x00200000) | ((X << 11) & 0x00100000)
                | ((X <<  3) & 0x00080000) | ((X >>  6) & 0x00040000)
                | ((X << 15) & 0x00020000) | ((X >>  4) & 0x00010000)
                | ((Y >>  2) & 0x00002000) | ((Y <<  8) & 0x00001000)
                | ((Y >> 14) & 0x00000808) | ((Y >>  9) & 0x00000400)
                | ((Y) & 0x00000200) | ((Y <<  7) & 0x00000100)
                | ((Y >>  7) & 0x00000020) | ((Y >>  3) & 0x00000011)
                | ((Y <<  2) & 0x00000004) | ((Y >> 21) & 0x00000002);
    }
}
#endif /* !MBEDTLS_DES_SETKEY_ALT */

/*
 * DES key schedule (56-bit, encryption)
 */
int mbedtls_des_setkey_enc(mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE])
{
    mbedtls_des_setkey(ctx->sk, key);

    return 0;
}

/*
 * DES key schedule (56-bit, decryption)
 */
int mbedtls_des_setkey_dec(mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE])
{
    int i;

    mbedtls_des_setkey(ctx->sk, key);

    for (i = 0; i < 16; i += 2) {
        SWAP(ctx->sk[i], ctx->sk[30 - i]);
        SWAP(ctx->sk[i + 1], ctx->sk[31 - i]);
    }

    return 0;
}

static void des3_set2key(uint32_t esk[96],
                         uint32_t dsk[96],
                         const unsigned char key[MBEDTLS_DES_KEY_SIZE*2])
{
    int i;

    mbedtls_des_setkey(esk, key);
    mbedtls_des_setkey(dsk + 32, key + 8);

    for (i = 0; i < 32; i += 2) {
        dsk[i] = esk[30 - i];
        dsk[i +  1] = esk[31 - i];

        esk[i + 32] = dsk[62 - i];
        esk[i + 33] = dsk[63 - i];

        esk[i + 64] = esk[i];
        esk[i + 65] = esk[i + 1];

        dsk[i + 64] = dsk[i];
        dsk[i + 65] = dsk[i + 1];
    }
}

/*
 * Triple-DES key schedule (112-bit, encryption)
 */
int mbedtls_des3_set2key_enc(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2])
{
    uint32_t sk[96];

    des3_set2key(ctx->sk, sk, key);
    mbedtls_platform_zeroize(sk,  sizeof(sk));

    return 0;
}

/*
 * Triple-DES key schedule (112-bit, decryption)
 */
int mbedtls_des3_set2key_dec(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2])
{
    uint32_t sk[96];

    des3_set2key(sk, ctx->sk, key);
    mbedtls_platform_zeroize(sk,  sizeof(sk));

    return 0;
}

static void des3_set3key(uint32_t esk[96],
                         uint32_t dsk[96],
                         const unsigned char key[24])
{
    int i;

    mbedtls_des_setkey(esk, key);
    mbedtls_des_setkey(dsk + 32, key +  8);
    mbedtls_des_setkey(esk + 64, key + 16);

    for (i = 0; i < 32; i += 2) {
        dsk[i] = esk[94 - i];
        dsk[i +  1] = esk[95 - i];

        esk[i + 32] = dsk[62 - i];
        esk[i + 33] = dsk[63 - i];

        dsk[i + 64] = esk[30 - i];
        dsk[i + 65] = esk[31 - i];
    }
}

/*
 * Triple-DES key schedule (168-bit, encryption)
 */
int mbedtls_des3_set3key_enc(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3])
{
    uint32_t sk[96];

    des3_set3key(ctx->sk, sk, key);
    mbedtls_platform_zeroize(sk,  sizeof(sk));

    return 0;
}

/*
 * Triple-DES key schedule (168-bit, decryption)
 */
int mbedtls_des3_set3key_dec(mbedtls_des3_context *ctx,
                             const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3])
{
    uint32_t sk[96];

    des3_set3key(sk, ctx->sk, key);
    mbedtls_platform_zeroize(sk,  sizeof(sk));

    return 0;
}

/*
 * DES-ECB block encryption/decryption
 */
#if !defined(MBEDTLS_DES_CRYPT_ECB_ALT)
int mbedtls_des_crypt_ecb(mbedtls_des_context *ctx,
                          const unsigned char input[8],
                          unsigned char output[8])
{
    int i;
    uint32_t X, Y, T, *SK;

    SK = ctx->sk;

    X = MBEDTLS_GET_UINT32_BE(input, 0);
    Y = MBEDTLS_GET_UINT32_BE(input, 4);

    DES_IP(X, Y);

    for (i = 0; i < 8; i++) {
        DES_ROUND(Y, X);
        DES_ROUND(X, Y);
    }

    DES_FP(Y, X);

    MBEDTLS_PUT_UINT32_BE(Y, output, 0);
    MBEDTLS_PUT_UINT32_BE(X, output, 4);

    return 0;
}
#endif /* !MBEDTLS_DES_CRYPT_ECB_ALT */

#if defined(MBEDTLS_CIPHER_MODE_CBC)
/*
 * DES-CBC buffer encryption/decryption
 */
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)
{
    int i;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char temp[8];

    if (length % 8) {
        return MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH;
    }

    if (mode == MBEDTLS_DES_ENCRYPT) {
        while (length > 0) {
            for (i = 0; i < 8; i++) {
                output[i] = (unsigned char) (input[i] ^ iv[i]);
            }

            ret = mbedtls_des_crypt_ecb(ctx, output, output);
            if (ret != 0) {
                goto exit;
            }
            memcpy(iv, output, 8);

            input  += 8;
            output += 8;
            length -= 8;
        }
    } else { /* MBEDTLS_DES_DECRYPT */
        while (length > 0) {
            memcpy(temp, input, 8);
            ret = mbedtls_des_crypt_ecb(ctx, input, output);
            if (ret != 0) {
                goto exit;
            }

            for (i = 0; i < 8; i++) {
                output[i] = (unsigned char) (output[i] ^ iv[i]);
            }

            memcpy(iv, temp, 8);

            input  += 8;
            output += 8;
            length -= 8;
        }
    }
    ret = 0;

exit:
    return ret;
}
#endif /* MBEDTLS_CIPHER_MODE_CBC */

/*
 * 3DES-ECB block encryption/decryption
 */
#if !defined(MBEDTLS_DES3_CRYPT_ECB_ALT)
int mbedtls_des3_crypt_ecb(mbedtls_des3_context *ctx,
                           const unsigned char input[8],
                           unsigned char output[8])
{
    int i;
    uint32_t X, Y, T, *SK;

    SK = ctx->sk;

    X = MBEDTLS_GET_UINT32_BE(input, 0);
    Y = MBEDTLS_GET_UINT32_BE(input, 4);

    DES_IP(X, Y);

    for (i = 0; i < 8; i++) {
        DES_ROUND(Y, X);
        DES_ROUND(X, Y);
    }

    for (i = 0; i < 8; i++) {
        DES_ROUND(X, Y);
        DES_ROUND(Y, X);
    }

    for (i = 0; i < 8; i++) {
        DES_ROUND(Y, X);
        DES_ROUND(X, Y);
    }

    DES_FP(Y, X);

    MBEDTLS_PUT_UINT32_BE(Y, output, 0);
    MBEDTLS_PUT_UINT32_BE(X, output, 4);

    return 0;
}
#endif /* !MBEDTLS_DES3_CRYPT_ECB_ALT */

#if defined(MBEDTLS_CIPHER_MODE_CBC)
/*
 * 3DES-CBC buffer encryption/decryption
 */
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)
{
    int i;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char temp[8];

    if (length % 8) {
        return MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH;
    }

    if (mode == MBEDTLS_DES_ENCRYPT) {
        while (length > 0) {
            for (i = 0; i < 8; i++) {
                output[i] = (unsigned char) (input[i] ^ iv[i]);
            }

            ret = mbedtls_des3_crypt_ecb(ctx, output, output);
            if (ret != 0) {
                goto exit;
            }
            memcpy(iv, output, 8);

            input  += 8;
            output += 8;
            length -= 8;
        }
    } else { /* MBEDTLS_DES_DECRYPT */
        while (length > 0) {
            memcpy(temp, input, 8);
            ret = mbedtls_des3_crypt_ecb(ctx, input, output);
            if (ret != 0) {
                goto exit;
            }

            for (i = 0; i < 8; i++) {
                output[i] = (unsigned char) (output[i] ^ iv[i]);
            }

            memcpy(iv, temp, 8);

            input  += 8;
            output += 8;
            length -= 8;
        }
    }
    ret = 0;

exit:
    return ret;
}
#endif /* MBEDTLS_CIPHER_MODE_CBC */

#endif /* !MBEDTLS_DES_ALT */

#if defined(MBEDTLS_SELF_TEST)
/*
 * DES and 3DES test vectors from:
 *
 * http://csrc.nist.gov/groups/STM/cavp/documents/des/tripledes-vectors.zip
 */
static const unsigned char des3_test_keys[24] =
{
    0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF,
    0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01,
    0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23
};

static const unsigned char des3_test_buf[8] =
{
    0x4E, 0x6F, 0x77, 0x20, 0x69, 0x73, 0x20, 0x74
};

static const unsigned char des3_test_ecb_dec[3][8] =
{
    { 0x37, 0x2B, 0x98, 0xBF, 0x52, 0x65, 0xB0, 0x59 },
    { 0xC2, 0x10, 0x19, 0x9C, 0x38, 0x5A, 0x65, 0xA1 },
    { 0xA2, 0x70, 0x56, 0x68, 0x69, 0xE5, 0x15, 0x1D }
};

static const unsigned char des3_test_ecb_enc[3][8] =
{
    { 0x1C, 0xD5, 0x97, 0xEA, 0x84, 0x26, 0x73, 0xFB },
    { 0xB3, 0x92, 0x4D, 0xF3, 0xC5, 0xB5, 0x42, 0x93 },
    { 0xDA, 0x37, 0x64, 0x41, 0xBA, 0x6F, 0x62, 0x6F }
};

#if defined(MBEDTLS_CIPHER_MODE_CBC)
static const unsigned char des3_test_iv[8] =
{
    0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF,
};

static const unsigned char des3_test_cbc_dec[3][8] =
{
    { 0x58, 0xD9, 0x48, 0xEF, 0x85, 0x14, 0x65, 0x9A },
    { 0x5F, 0xC8, 0x78, 0xD4, 0xD7, 0x92, 0xD9, 0x54 },
    { 0x25, 0xF9, 0x75, 0x85, 0xA8, 0x1E, 0x48, 0xBF }
};

static const unsigned char des3_test_cbc_enc[3][8] =
{
    { 0x91, 0x1C, 0x6D, 0xCF, 0x48, 0xA7, 0xC3, 0x4D },
    { 0x60, 0x1A, 0x76, 0x8F, 0xA1, 0xF9, 0x66, 0xF1 },
    { 0xA1, 0x50, 0x0F, 0x99, 0xB2, 0xCD, 0x64, 0x76 }
};
#endif /* MBEDTLS_CIPHER_MODE_CBC */

/*
 * Checkup routine
 */
int mbedtls_des_self_test(int verbose)
{
    int i, j, u, v, ret = 0;
    mbedtls_des_context ctx;
    mbedtls_des3_context ctx3;
    unsigned char buf[8];
#if defined(MBEDTLS_CIPHER_MODE_CBC)
    unsigned char prv[8];
    unsigned char iv[8];
#endif

    mbedtls_des_init(&ctx);
    mbedtls_des3_init(&ctx3);
    /*
     * ECB mode
     */
    for (i = 0; i < 6; i++) {
        u = i >> 1;
        v = i  & 1;

        if (verbose != 0) {
            mbedtls_printf("  DES%c-ECB-%3d (%s): ",
                           (u == 0) ? ' ' : '3', 56 + u * 56,
                           (v == MBEDTLS_DES_DECRYPT) ? "dec" : "enc");
        }

        memcpy(buf, des3_test_buf, 8);

        switch (i) {
            case 0:
                ret = mbedtls_des_setkey_dec(&ctx, des3_test_keys);
                break;

            case 1:
                ret = mbedtls_des_setkey_enc(&ctx, des3_test_keys);
                break;

            case 2:
                ret = mbedtls_des3_set2key_dec(&ctx3, des3_test_keys);
                break;

            case 3:
                ret = mbedtls_des3_set2key_enc(&ctx3, des3_test_keys);
                break;

            case 4:
                ret = mbedtls_des3_set3key_dec(&ctx3, des3_test_keys);
                break;

            case 5:
                ret = mbedtls_des3_set3key_enc(&ctx3, des3_test_keys);
                break;

            default:
                return 1;
        }
        if (ret != 0) {
            goto exit;
        }

        for (j = 0; j < 100; j++) {
            if (u == 0) {
                ret = mbedtls_des_crypt_ecb(&ctx, buf, buf);
            } else {
                ret = mbedtls_des3_crypt_ecb(&ctx3, buf, buf);
            }
            if (ret != 0) {
                goto exit;
            }
        }

        if ((v == MBEDTLS_DES_DECRYPT &&
             memcmp(buf, des3_test_ecb_dec[u], 8) != 0) ||
            (v != MBEDTLS_DES_DECRYPT &&
             memcmp(buf, des3_test_ecb_enc[u], 8) != 0)) {
            if (verbose != 0) {
                mbedtls_printf("failed\n");
            }

            ret = 1;
            goto exit;
        }

        if (verbose != 0) {
            mbedtls_printf("passed\n");
        }
    }

    if (verbose != 0) {
        mbedtls_printf("\n");
    }

#if defined(MBEDTLS_CIPHER_MODE_CBC)
    /*
     * CBC mode
     */
    for (i = 0; i < 6; i++) {
        u = i >> 1;
        v = i  & 1;

        if (verbose != 0) {
            mbedtls_printf("  DES%c-CBC-%3d (%s): ",
                           (u == 0) ? ' ' : '3', 56 + u * 56,
                           (v == MBEDTLS_DES_DECRYPT) ? "dec" : "enc");
        }

        memcpy(iv,  des3_test_iv,  8);
        memcpy(prv, des3_test_iv,  8);
        memcpy(buf, des3_test_buf, 8);

        switch (i) {
            case 0:
                ret = mbedtls_des_setkey_dec(&ctx, des3_test_keys);
                break;

            case 1:
                ret = mbedtls_des_setkey_enc(&ctx, des3_test_keys);
                break;

            case 2:
                ret = mbedtls_des3_set2key_dec(&ctx3, des3_test_keys);
                break;

            case 3:
                ret = mbedtls_des3_set2key_enc(&ctx3, des3_test_keys);
                break;

            case 4:
                ret = mbedtls_des3_set3key_dec(&ctx3, des3_test_keys);
                break;

            case 5:
                ret = mbedtls_des3_set3key_enc(&ctx3, des3_test_keys);
                break;

            default:
                return 1;
        }
        if (ret != 0) {
            goto exit;
        }

        if (v == MBEDTLS_DES_DECRYPT) {
            for (j = 0; j < 100; j++) {
                if (u == 0) {
                    ret = mbedtls_des_crypt_cbc(&ctx, v, 8, iv, buf, buf);
                } else {
                    ret = mbedtls_des3_crypt_cbc(&ctx3, v, 8, iv, buf, buf);
                }
                if (ret != 0) {
                    goto exit;
                }
            }
        } else {
            for (j = 0; j < 100; j++) {
                unsigned char tmp[8];

                if (u == 0) {
                    ret = mbedtls_des_crypt_cbc(&ctx, v, 8, iv, buf, buf);
                } else {
                    ret = mbedtls_des3_crypt_cbc(&ctx3, v, 8, iv, buf, buf);
                }
                if (ret != 0) {
                    goto exit;
                }

                memcpy(tmp, prv, 8);
                memcpy(prv, buf, 8);
                memcpy(buf, tmp, 8);
            }

            memcpy(buf, prv, 8);
        }

        if ((v == MBEDTLS_DES_DECRYPT &&
             memcmp(buf, des3_test_cbc_dec[u], 8) != 0) ||
            (v != MBEDTLS_DES_DECRYPT &&
             memcmp(buf, des3_test_cbc_enc[u], 8) != 0)) {
            if (verbose != 0) {
                mbedtls_printf("failed\n");
            }

            ret = 1;
            goto exit;
        }

        if (verbose != 0) {
            mbedtls_printf("passed\n");
        }
    }
#endif /* MBEDTLS_CIPHER_MODE_CBC */

    if (verbose != 0) {
        mbedtls_printf("\n");
    }

exit:
    mbedtls_des_free(&ctx);
    mbedtls_des3_free(&ctx3);

    if (ret != 0) {
        ret = 1;
    }
    return ret;
}

#endif /* MBEDTLS_SELF_TEST */

#endif /* MBEDTLS_DES_C */