des.c 14.4 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
/*
 * DES encryption/decryption
 * Copyright (c) 2007 Reimar Doeffinger
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <inttypes.h>
22
#include "common.h"
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331
#include "des.h"

#define T(a, b, c, d, e, f, g, h) 64-a,64-b,64-c,64-d,64-e,64-f,64-g,64-h
static const uint8_t IP_shuffle[] = {
    T(58, 50, 42, 34, 26, 18, 10, 2),
    T(60, 52, 44, 36, 28, 20, 12, 4),
    T(62, 54, 46, 38, 30, 22, 14, 6),
    T(64, 56, 48, 40, 32, 24, 16, 8),
    T(57, 49, 41, 33, 25, 17,  9, 1),
    T(59, 51, 43, 35, 27, 19, 11, 3),
    T(61, 53, 45, 37, 29, 21, 13, 5),
    T(63, 55, 47, 39, 31, 23, 15, 7)
};
#undef T

#define T(a, b, c, d) 32-a,32-b,32-c,32-d
static const uint8_t P_shuffle[] = {
    T(16,  7, 20, 21),
    T(29, 12, 28, 17),
    T( 1, 15, 23, 26),
    T( 5, 18, 31, 10),
    T( 2,  8, 24, 14),
    T(32, 27,  3,  9),
    T(19, 13, 30,  6),
    T(22, 11,  4, 25)
};
#undef T

#define T(a, b, c, d, e, f, g) 64-a,64-b,64-c,64-d,64-e,64-f,64-g
static const uint8_t PC1_shuffle[] = {
    T(57, 49, 41, 33, 25, 17,  9),
    T( 1, 58, 50, 42, 34, 26, 18),
    T(10,  2, 59, 51, 43, 35, 27),
    T(19, 11,  3, 60, 52, 44, 36),
    T(63, 55, 47, 39, 31, 23, 15),
    T( 7, 62, 54, 46, 38, 30, 22),
    T(14,  6, 61, 53, 45, 37, 29),
    T(21, 13,  5, 28, 20, 12,  4)
};
#undef T

#define T(a, b, c, d, e, f) 56-a,56-b,56-c,56-d,56-e,56-f
static const uint8_t PC2_shuffle[] = {
    T(14, 17, 11, 24,  1,  5),
    T( 3, 28, 15,  6, 21, 10),
    T(23, 19, 12,  4, 26,  8),
    T(16,  7, 27, 20, 13,  2),
    T(41, 52, 31, 37, 47, 55),
    T(30, 40, 51, 45, 33, 48),
    T(44, 49, 39, 56, 34, 53),
    T(46, 42, 50, 36, 29, 32)
};
#undef T

#ifdef CONFIG_SMALL
static const uint8_t S_boxes[8][32] = {
    {
    0x0e, 0xf4, 0x7d, 0x41, 0xe2, 0x2f, 0xdb, 0x18, 0xa3, 0x6a, 0xc6, 0xbc, 0x95, 0x59, 0x30, 0x87,
    0xf4, 0xc1, 0x8e, 0x28, 0x4d, 0x96, 0x12, 0x7b, 0x5f, 0xbc, 0x39, 0xe7, 0xa3, 0x0a, 0x65, 0xd0,
    }, {
    0x3f, 0xd1, 0x48, 0x7e, 0xf6, 0x2b, 0x83, 0xe4, 0xc9, 0x07, 0x12, 0xad, 0x6c, 0x90, 0xb5, 0x5a,
    0xd0, 0x8e, 0xa7, 0x1b, 0x3a, 0xf4, 0x4d, 0x21, 0xb5, 0x68, 0x7c, 0xc6, 0x09, 0x53, 0xe2, 0x9f,
    }, {
    0xda, 0x70, 0x09, 0x9e, 0x36, 0x43, 0x6f, 0xa5, 0x21, 0x8d, 0x5c, 0xe7, 0xcb, 0xb4, 0xf2, 0x18,
    0x1d, 0xa6, 0xd4, 0x09, 0x68, 0x9f, 0x83, 0x70, 0x4b, 0xf1, 0xe2, 0x3c, 0xb5, 0x5a, 0x2e, 0xc7,
    }, {
    0xd7, 0x8d, 0xbe, 0x53, 0x60, 0xf6, 0x09, 0x3a, 0x41, 0x72, 0x28, 0xc5, 0x1b, 0xac, 0xe4, 0x9f,
    0x3a, 0xf6, 0x09, 0x60, 0xac, 0x1b, 0xd7, 0x8d, 0x9f, 0x41, 0x53, 0xbe, 0xc5, 0x72, 0x28, 0xe4,
    }, {
    0xe2, 0xbc, 0x24, 0xc1, 0x47, 0x7a, 0xdb, 0x16, 0x58, 0x05, 0xf3, 0xaf, 0x3d, 0x90, 0x8e, 0x69,
    0xb4, 0x82, 0xc1, 0x7b, 0x1a, 0xed, 0x27, 0xd8, 0x6f, 0xf9, 0x0c, 0x95, 0xa6, 0x43, 0x50, 0x3e,
    }, {
    0xac, 0xf1, 0x4a, 0x2f, 0x79, 0xc2, 0x96, 0x58, 0x60, 0x1d, 0xd3, 0xe4, 0x0e, 0xb7, 0x35, 0x8b,
    0x49, 0x3e, 0x2f, 0xc5, 0x92, 0x58, 0xfc, 0xa3, 0xb7, 0xe0, 0x14, 0x7a, 0x61, 0x0d, 0x8b, 0xd6,
    }, {
    0xd4, 0x0b, 0xb2, 0x7e, 0x4f, 0x90, 0x18, 0xad, 0xe3, 0x3c, 0x59, 0xc7, 0x25, 0xfa, 0x86, 0x61,
    0x61, 0xb4, 0xdb, 0x8d, 0x1c, 0x43, 0xa7, 0x7e, 0x9a, 0x5f, 0x06, 0xf8, 0xe0, 0x25, 0x39, 0xc2,
    }, {
    0x1d, 0xf2, 0xd8, 0x84, 0xa6, 0x3f, 0x7b, 0x41, 0xca, 0x59, 0x63, 0xbe, 0x05, 0xe0, 0x9c, 0x27,
    0x27, 0x1b, 0xe4, 0x71, 0x49, 0xac, 0x8e, 0xd2, 0xf0, 0xc6, 0x9a, 0x0d, 0x3f, 0x53, 0x65, 0xb8,
    }
};
#else
/**
 * This table contains the results of applying both the S-box and P-shuffle.
 * It can be regenerated by compiling this file with -DCONFIG_SMALL -DTEST -DGENTABLES
 */
static const uint32_t S_boxes_P_shuffle[8][64] = {
    {
    0x00808200, 0x00000000, 0x00008000, 0x00808202, 0x00808002, 0x00008202, 0x00000002, 0x00008000,
    0x00000200, 0x00808200, 0x00808202, 0x00000200, 0x00800202, 0x00808002, 0x00800000, 0x00000002,
    0x00000202, 0x00800200, 0x00800200, 0x00008200, 0x00008200, 0x00808000, 0x00808000, 0x00800202,
    0x00008002, 0x00800002, 0x00800002, 0x00008002, 0x00000000, 0x00000202, 0x00008202, 0x00800000,
    0x00008000, 0x00808202, 0x00000002, 0x00808000, 0x00808200, 0x00800000, 0x00800000, 0x00000200,
    0x00808002, 0x00008000, 0x00008200, 0x00800002, 0x00000200, 0x00000002, 0x00800202, 0x00008202,
    0x00808202, 0x00008002, 0x00808000, 0x00800202, 0x00800002, 0x00000202, 0x00008202, 0x00808200,
    0x00000202, 0x00800200, 0x00800200, 0x00000000, 0x00008002, 0x00008200, 0x00000000, 0x00808002,
    },
    {
    0x40084010, 0x40004000, 0x00004000, 0x00084010, 0x00080000, 0x00000010, 0x40080010, 0x40004010,
    0x40000010, 0x40084010, 0x40084000, 0x40000000, 0x40004000, 0x00080000, 0x00000010, 0x40080010,
    0x00084000, 0x00080010, 0x40004010, 0x00000000, 0x40000000, 0x00004000, 0x00084010, 0x40080000,
    0x00080010, 0x40000010, 0x00000000, 0x00084000, 0x00004010, 0x40084000, 0x40080000, 0x00004010,
    0x00000000, 0x00084010, 0x40080010, 0x00080000, 0x40004010, 0x40080000, 0x40084000, 0x00004000,
    0x40080000, 0x40004000, 0x00000010, 0x40084010, 0x00084010, 0x00000010, 0x00004000, 0x40000000,
    0x00004010, 0x40084000, 0x00080000, 0x40000010, 0x00080010, 0x40004010, 0x40000010, 0x00080010,
    0x00084000, 0x00000000, 0x40004000, 0x00004010, 0x40000000, 0x40080010, 0x40084010, 0x00084000,
    },
    {
    0x00000104, 0x04010100, 0x00000000, 0x04010004, 0x04000100, 0x00000000, 0x00010104, 0x04000100,
    0x00010004, 0x04000004, 0x04000004, 0x00010000, 0x04010104, 0x00010004, 0x04010000, 0x00000104,
    0x04000000, 0x00000004, 0x04010100, 0x00000100, 0x00010100, 0x04010000, 0x04010004, 0x00010104,
    0x04000104, 0x00010100, 0x00010000, 0x04000104, 0x00000004, 0x04010104, 0x00000100, 0x04000000,
    0x04010100, 0x04000000, 0x00010004, 0x00000104, 0x00010000, 0x04010100, 0x04000100, 0x00000000,
    0x00000100, 0x00010004, 0x04010104, 0x04000100, 0x04000004, 0x00000100, 0x00000000, 0x04010004,
    0x04000104, 0x00010000, 0x04000000, 0x04010104, 0x00000004, 0x00010104, 0x00010100, 0x04000004,
    0x04010000, 0x04000104, 0x00000104, 0x04010000, 0x00010104, 0x00000004, 0x04010004, 0x00010100,
    },
    {
    0x80401000, 0x80001040, 0x80001040, 0x00000040, 0x00401040, 0x80400040, 0x80400000, 0x80001000,
    0x00000000, 0x00401000, 0x00401000, 0x80401040, 0x80000040, 0x00000000, 0x00400040, 0x80400000,
    0x80000000, 0x00001000, 0x00400000, 0x80401000, 0x00000040, 0x00400000, 0x80001000, 0x00001040,
    0x80400040, 0x80000000, 0x00001040, 0x00400040, 0x00001000, 0x00401040, 0x80401040, 0x80000040,
    0x00400040, 0x80400000, 0x00401000, 0x80401040, 0x80000040, 0x00000000, 0x00000000, 0x00401000,
    0x00001040, 0x00400040, 0x80400040, 0x80000000, 0x80401000, 0x80001040, 0x80001040, 0x00000040,
    0x80401040, 0x80000040, 0x80000000, 0x00001000, 0x80400000, 0x80001000, 0x00401040, 0x80400040,
    0x80001000, 0x00001040, 0x00400000, 0x80401000, 0x00000040, 0x00400000, 0x00001000, 0x00401040,
    },
    {
    0x00000080, 0x01040080, 0x01040000, 0x21000080, 0x00040000, 0x00000080, 0x20000000, 0x01040000,
    0x20040080, 0x00040000, 0x01000080, 0x20040080, 0x21000080, 0x21040000, 0x00040080, 0x20000000,
    0x01000000, 0x20040000, 0x20040000, 0x00000000, 0x20000080, 0x21040080, 0x21040080, 0x01000080,
    0x21040000, 0x20000080, 0x00000000, 0x21000000, 0x01040080, 0x01000000, 0x21000000, 0x00040080,
    0x00040000, 0x21000080, 0x00000080, 0x01000000, 0x20000000, 0x01040000, 0x21000080, 0x20040080,
    0x01000080, 0x20000000, 0x21040000, 0x01040080, 0x20040080, 0x00000080, 0x01000000, 0x21040000,
    0x21040080, 0x00040080, 0x21000000, 0x21040080, 0x01040000, 0x00000000, 0x20040000, 0x21000000,
    0x00040080, 0x01000080, 0x20000080, 0x00040000, 0x00000000, 0x20040000, 0x01040080, 0x20000080,
    },
    {
    0x10000008, 0x10200000, 0x00002000, 0x10202008, 0x10200000, 0x00000008, 0x10202008, 0x00200000,
    0x10002000, 0x00202008, 0x00200000, 0x10000008, 0x00200008, 0x10002000, 0x10000000, 0x00002008,
    0x00000000, 0x00200008, 0x10002008, 0x00002000, 0x00202000, 0x10002008, 0x00000008, 0x10200008,
    0x10200008, 0x00000000, 0x00202008, 0x10202000, 0x00002008, 0x00202000, 0x10202000, 0x10000000,
    0x10002000, 0x00000008, 0x10200008, 0x00202000, 0x10202008, 0x00200000, 0x00002008, 0x10000008,
    0x00200000, 0x10002000, 0x10000000, 0x00002008, 0x10000008, 0x10202008, 0x00202000, 0x10200000,
    0x00202008, 0x10202000, 0x00000000, 0x10200008, 0x00000008, 0x00002000, 0x10200000, 0x00202008,
    0x00002000, 0x00200008, 0x10002008, 0x00000000, 0x10202000, 0x10000000, 0x00200008, 0x10002008,
    },
    {
    0x00100000, 0x02100001, 0x02000401, 0x00000000, 0x00000400, 0x02000401, 0x00100401, 0x02100400,
    0x02100401, 0x00100000, 0x00000000, 0x02000001, 0x00000001, 0x02000000, 0x02100001, 0x00000401,
    0x02000400, 0x00100401, 0x00100001, 0x02000400, 0x02000001, 0x02100000, 0x02100400, 0x00100001,
    0x02100000, 0x00000400, 0x00000401, 0x02100401, 0x00100400, 0x00000001, 0x02000000, 0x00100400,
    0x02000000, 0x00100400, 0x00100000, 0x02000401, 0x02000401, 0x02100001, 0x02100001, 0x00000001,
    0x00100001, 0x02000000, 0x02000400, 0x00100000, 0x02100400, 0x00000401, 0x00100401, 0x02100400,
    0x00000401, 0x02000001, 0x02100401, 0x02100000, 0x00100400, 0x00000000, 0x00000001, 0x02100401,
    0x00000000, 0x00100401, 0x02100000, 0x00000400, 0x02000001, 0x02000400, 0x00000400, 0x00100001,
    },
    {
    0x08000820, 0x00000800, 0x00020000, 0x08020820, 0x08000000, 0x08000820, 0x00000020, 0x08000000,
    0x00020020, 0x08020000, 0x08020820, 0x00020800, 0x08020800, 0x00020820, 0x00000800, 0x00000020,
    0x08020000, 0x08000020, 0x08000800, 0x00000820, 0x00020800, 0x00020020, 0x08020020, 0x08020800,
    0x00000820, 0x00000000, 0x00000000, 0x08020020, 0x08000020, 0x08000800, 0x00020820, 0x00020000,
    0x00020820, 0x00020000, 0x08020800, 0x00000800, 0x00000020, 0x08020020, 0x00000800, 0x00020820,
    0x08000800, 0x00000020, 0x08000020, 0x08020000, 0x08020020, 0x08000000, 0x00020000, 0x08000820,
    0x00000000, 0x08020820, 0x00020020, 0x08000020, 0x08020000, 0x08000800, 0x08000820, 0x00000000,
    0x08020820, 0x00020800, 0x00020800, 0x00000820, 0x00000820, 0x00020020, 0x08000000, 0x08020800,
    },
};
#endif

static uint64_t shuffle(uint64_t in, const uint8_t *shuffle, int shuffle_len) {
    int i;
    uint64_t res = 0;
    for (i = 0; i < shuffle_len; i++)
        res += res + ((in >> *shuffle++) & 1);
    return res;
}

static uint64_t shuffle_inv(uint64_t in, const uint8_t *shuffle, int shuffle_len) {
    int i;
    uint64_t res = 0;
    shuffle += shuffle_len - 1;
    for (i = 0; i < shuffle_len; i++) {
        res |= (in & 1) << *shuffle--;
        in >>= 1;
    }
    return res;
}

static uint32_t f_func(uint32_t r, uint64_t k) {
    int i;
    uint32_t out = 0;
    // rotate to get first part of E-shuffle in the lowest 6 bits
    r = (r << 1) | (r >> 31);
    // apply S-boxes, those compress the data again from 8 * 6 to 8 * 4 bits
    for (i = 7; i >= 0; i--) {
        uint8_t tmp = (r ^ k) & 0x3f;
#ifdef CONFIG_SMALL
        uint8_t v = S_boxes[i][tmp >> 1];
        if (tmp & 1) v >>= 4;
        out = (out >> 4) | (v << 28);
#else
        out |= S_boxes_P_shuffle[i][tmp];
#endif
        // get next 6 bits of E-shuffle and round key k into the lowest bits
        r = (r >> 4) | (r << 28);
        k >>= 6;
    }
#ifdef CONFIG_SMALL
    out = shuffle(out, P_shuffle, sizeof(P_shuffle));
#endif
    return out;
}

/**
 * \brief rotate the two halves of the expanded 56 bit key each 1 bit left
 *
 * Note: the specification calls this "shift", so I kept it although
 * it is confusing.
 */
static uint64_t key_shift_left(uint64_t CDn) {
    uint64_t carries = (CDn >> 27) & 0x10000001;
    CDn <<= 1;
    CDn &= ~0x10000001;
    CDn |= carries;
    return CDn;
}

uint64_t ff_des_encdec(uint64_t in, uint64_t key, int decrypt) {
    int i;
    uint64_t K[16];
    // discard parity bits from key and shuffle it into C and D parts
    uint64_t CDn = shuffle(key, PC1_shuffle, sizeof(PC1_shuffle));
    // generate round keys
    for (i = 0; i < 16; i++) {
        CDn = key_shift_left(CDn);
        if (i > 1 && i != 8 && i != 15)
            CDn = key_shift_left(CDn);
        K[i] = shuffle(CDn, PC2_shuffle, sizeof(PC2_shuffle));
    }
    // used to apply round keys in reverse order for decryption
    decrypt = decrypt ? 15 : 0;
    // shuffle irrelevant to security but to ease hardware implementations
    in = shuffle(in, IP_shuffle, sizeof(IP_shuffle));
    for (i = 0; i < 16; i++) {
        uint32_t f_res;
        f_res = f_func(in, K[decrypt ^ i]);
        in = (in << 32) | (in >> 32);
        in ^= f_res;
    }
    in = (in << 32) | (in >> 32);
    // reverse shuffle used to ease hardware implementations
    in = shuffle_inv(in, IP_shuffle, sizeof(IP_shuffle));
    return in;
}

#ifdef TEST
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
static uint64_t rand64(void) {
    uint64_t r = rand();
    r = (r << 32) | rand();
    return r;
}

int main(void) {
    int i, j;
    struct timeval tv;
    uint64_t key;
    uint64_t data;
    uint64_t ct;
    gettimeofday(&tv, NULL);
    srand(tv.tv_sec * 1000 * 1000 + tv.tv_usec);
    key = 0x123456789abcdef0ULL;
    data = 0xfedcba9876543210ULL;
    if (ff_des_encdec(data, key, 0) != 0x4ab65b3d4b061518ULL) {
        printf("Test 1 failed\n");
        return 1;
    }
    for (i = 0; i < 1000000; i++) {
        key = rand64();
        data = rand64();
        ct = ff_des_encdec(data, key, 0);
        if (ff_des_encdec(ct, key, 1) != data) {
            printf("Test 2 failed\n");
            return 1;
        }
    }
#ifdef GENTABLES
    printf("static const uint32_t S_boxes_P_shuffle[8][64] = {\n");
    for (i = 0; i < 8; i++) {
        printf("    {");
        for (j = 0; j < 64; j++) {
            uint32_t v = S_boxes[i][j >> 1];
            v = j & 1 ? v >> 4 : v & 0xf;
            v <<= 28 - 4 * i;
            v = shuffle(v, P_shuffle, sizeof(P_shuffle));
            printf((j & 7) == 0 ? "\n    " : " ");
            printf("0x%08X,", v);
        }
        printf("\n    },\n");
    }
    printf("};\n");
#endif
    return 0;
}
#endif