des.c

这是由Rinick编写的加解密函数库。最近找了不少关于加解密的C源码

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [e-mail], http://libtomcrypt.org
 */
#include "tomcrypt.h"

/** 
  @file des.c
  DES code submitted by Dobes Vandermeer 
*/

#ifdef DES

#define EN0 0 
#define DE1 1

const struct ltc_cipher_descriptor des_desc =
{
    "des",
    13,
    8, 8, 8, 16,
    &des_setup,
    &des_ecb_encrypt,
    &des_ecb_decrypt,
    &des_test,
    &des_done,
    &des_keysize,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

const struct ltc_cipher_descriptor des3_desc =
{
    "3des",
    14,
    24, 24, 8, 16,
    &des3_setup,
    &des3_ecb_encrypt,
    &des3_ecb_decrypt,
    &des3_test,
    &des3_done,
    &des3_keysize,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

static const ulong32 bytebit[8] =
{
    0200, 0100, 040, 020, 010, 04, 02, 01 
};

static const ulong32 bigbyte[24] =
{
    0x800000UL,  0x400000UL,  0x200000UL,  0x100000UL,
    0x80000UL,   0x40000UL,   0x20000UL,   0x10000UL,
    0x8000UL,    0x4000UL,    0x2000UL,    0x1000UL,
    0x800UL,     0x400UL,     0x200UL,     0x100UL,
    0x80UL,      0x40UL,      0x20UL,      0x10UL,
    0x8UL,       0x4UL,       0x2UL,       0x1L 
};

/* Use the key schedule specific in the standard (ANSI X3.92-1981) */

static const unsigned char pc1[56] = {
    56, 48, 40, 32, 24, 16,  8,  0, 57, 49, 41, 33, 25, 17,  
     9,  1, 58, 50, 42, 34, 26, 18, 10,  2, 59, 51, 43, 35, 
    62, 54, 46, 38, 30, 22, 14,  6, 61, 53, 45, 37, 29, 21,
    13,  5, 60, 52, 44, 36, 28, 20, 12,  4, 27, 19, 11,  3 
};

static const unsigned char totrot[16] = {
    1,   2,  4,  6,
    8,  10, 12, 14, 
    15, 17, 19, 21, 
    23, 25, 27, 28
};

static const unsigned char pc2[48] = {
    13, 16, 10, 23,  0,  4,      2, 27, 14,  5, 20,  9,
    22, 18, 11,  3, 25,  7,     15,  6, 26, 19, 12,  1,
    40, 51, 30, 36, 46, 54,     29, 39, 50, 44, 32, 47,
    43, 48, 38, 55, 33, 52,     45, 41, 49, 35, 28, 31
};


static const ulong32 SP1[64] =
{
    0x01010400UL, 0x00000000UL, 0x00010000UL, 0x01010404UL,
    0x01010004UL, 0x00010404UL, 0x00000004UL, 0x00010000UL,
    0x00000400UL, 0x01010400UL, 0x01010404UL, 0x00000400UL,
    0x01000404UL, 0x01010004UL, 0x01000000UL, 0x00000004UL,
    0x00000404UL, 0x01000400UL, 0x01000400UL, 0x00010400UL,
    0x00010400UL, 0x01010000UL, 0x01010000UL, 0x01000404UL,
    0x00010004UL, 0x01000004UL, 0x01000004UL, 0x00010004UL,
    0x00000000UL, 0x00000404UL, 0x00010404UL, 0x01000000UL,
    0x00010000UL, 0x01010404UL, 0x00000004UL, 0x01010000UL,
    0x01010400UL, 0x01000000UL, 0x01000000UL, 0x00000400UL,
    0x01010004UL, 0x00010000UL, 0x00010400UL, 0x01000004UL,
    0x00000400UL, 0x00000004UL, 0x01000404UL, 0x00010404UL,
    0x01010404UL, 0x00010004UL, 0x01010000UL, 0x01000404UL,
    0x01000004UL, 0x00000404UL, 0x00010404UL, 0x01010400UL,
    0x00000404UL, 0x01000400UL, 0x01000400UL, 0x00000000UL,
    0x00010004UL, 0x00010400UL, 0x00000000UL, 0x01010004UL
};

static const ulong32 SP2[64] =
{
    0x80108020UL, 0x80008000UL, 0x00008000UL, 0x00108020UL,
    0x00100000UL, 0x00000020UL, 0x80100020UL, 0x80008020UL,
    0x80000020UL, 0x80108020UL, 0x80108000UL, 0x80000000UL,
    0x80008000UL, 0x00100000UL, 0x00000020UL, 0x80100020UL,
    0x00108000UL, 0x00100020UL, 0x80008020UL, 0x00000000UL,
    0x80000000UL, 0x00008000UL, 0x00108020UL, 0x80100000UL,
    0x00100020UL, 0x80000020UL, 0x00000000UL, 0x00108000UL,
    0x00008020UL, 0x80108000UL, 0x80100000UL, 0x00008020UL,
    0x00000000UL, 0x00108020UL, 0x80100020UL, 0x00100000UL,
    0x80008020UL, 0x80100000UL, 0x80108000UL, 0x00008000UL,
    0x80100000UL, 0x80008000UL, 0x00000020UL, 0x80108020UL,
    0x00108020UL, 0x00000020UL, 0x00008000UL, 0x80000000UL,
    0x00008020UL, 0x80108000UL, 0x00100000UL, 0x80000020UL,
    0x00100020UL, 0x80008020UL, 0x80000020UL, 0x00100020UL,
    0x00108000UL, 0x00000000UL, 0x80008000UL, 0x00008020UL,
    0x80000000UL, 0x80100020UL, 0x80108020UL, 0x00108000UL
};

static const ulong32 SP3[64] =
{
    0x00000208UL, 0x08020200UL, 0x00000000UL, 0x08020008UL,
    0x08000200UL, 0x00000000UL, 0x00020208UL, 0x08000200UL,
    0x00020008UL, 0x08000008UL, 0x08000008UL, 0x00020000UL,
    0x08020208UL, 0x00020008UL, 0x08020000UL, 0x00000208UL,
    0x08000000UL, 0x00000008UL, 0x08020200UL, 0x00000200UL,
    0x00020200UL, 0x08020000UL, 0x08020008UL, 0x00020208UL,
    0x08000208UL, 0x00020200UL, 0x00020000UL, 0x08000208UL,
    0x00000008UL, 0x08020208UL, 0x00000200UL, 0x08000000UL,
    0x08020200UL, 0x08000000UL, 0x00020008UL, 0x00000208UL,
    0x00020000UL, 0x08020200UL, 0x08000200UL, 0x00000000UL,
    0x00000200UL, 0x00020008UL, 0x08020208UL, 0x08000200UL,
    0x08000008UL, 0x00000200UL, 0x00000000UL, 0x08020008UL,
    0x08000208UL, 0x00020000UL, 0x08000000UL, 0x08020208UL,
    0x00000008UL, 0x00020208UL, 0x00020200UL, 0x08000008UL,