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ffmpeg/libavutil/des.c
Reimar Döffinger 2e9ad69aaf Add support for DES en- and decryption.
Originally committed as revision 10810 to svn://svn.ffmpeg.org/ffmpeg/trunk
2007-10-19 09:31:41 +00:00

331 lines
14 KiB
C

/*
* 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>
#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