/* 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, tomstdenis@iahu.ca, http://libtomcrypt.org *//* MD2 (RFC 1319) hash function implementation by Tom St Denis */#include "mycrypt.h"#ifdef MD2const struct _hash_descriptor md2_desc ={    "md2",    7,    16,    16,    /* DER encoding */    { 0x30, 0x20, 0x30, 0x0C, 0x06, 0x08, 0x2A, 0x86,       0x48, 0x86, 0xF7, 0x0D, 0x02, 0x02, 0x05, 0x00,       0x04, 0x10 },    18,    &md2_init,    &md2_process,    &md2_done,    &md2_test};static const unsigned char PI_SUBST[256] = {  41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,  19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,  76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,  138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,  245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,  148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,  39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,  181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,  150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,  112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,  96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,  85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,  234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,  129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,  8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,  203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,  166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,  31, 26, 219, 153, 141, 51, 159, 17, 131, 20};/* adds 16 bytes to the checksum */static void md2_update_chksum(hash_state *md){   int j;   unsigned char L;   L = md->md2.chksum[15];   for (j = 0; j < 16; j++) {/* caution, the RFC says its "C[j] = S[M[i*16+j] xor L]" but the reference source code [and test vectors] say    otherwise.*/       L = (md->md2.chksum[j] ^= PI_SUBST[(int)(md->md2.buf[j] ^ L)] & 255);   }}static void md2_compress(hash_state *md){   int j, k;   unsigned char t;      /* copy block */   for (j = 0; j < 16; j++) {       md->md2.X[16+j] = md->md2.buf[j];       md->md2.X[32+j] = md->md2.X[j] ^ md->md2.X[16+j];   }   t = (unsigned char)0;   /* do 18 rounds */   for (j = 0; j < 18; j++) {       for (k = 0; k < 48; k++) {           t = (md->md2.X[k] ^= PI_SUBST[(int)(t & 255)]);       }       t = (t + (unsigned char)j) & 255;   }}void md2_init(hash_state *md){   _ARGCHK(md != NULL);   /* MD2 uses a zero'ed state... */   zeromem(md->md2.X, sizeof(md->md2.X));   zeromem(md->md2.chksum, sizeof(md->md2.chksum));   zeromem(md->md2.buf, sizeof(md->md2.buf));   md->md2.curlen = 0;}int md2_process(hash_state *md, const unsigned char *buf, unsigned long len){    unsigned long n;    _ARGCHK(md != NULL);    _ARGCHK(buf != NULL);    if (md-> md2 .curlen > sizeof(md-> md2 .buf)) {                                   return CRYPT_INVALID_ARG;                                                               }                                                                                           while (len > 0) {        n = MIN(len, (16 - md->md2.curlen));        memcpy(md->md2.buf + md->md2.curlen, buf, (size_t)n);        md->md2.curlen += n;        buf            += n;        len            -= n;        /* is 16 bytes full? */        if (md->md2.curlen == 16) {            md2_compress(md);            md2_update_chksum(md);            md->md2.curlen = 0;        }    }    return CRYPT_OK;}int md2_done(hash_state * md, unsigned char *hash){    unsigned long i, k;    _ARGCHK(md != NULL);    _ARGCHK(hash != NULL);    if (md->md2.curlen >= sizeof(md->md2.buf)) {       return CRYPT_INVALID_ARG;    }    /* pad the message */    k = 16 - md->md2.curlen;    for (i = md->md2.curlen; i < 16; i++) {        md->md2.buf[i] = (unsigned char)k;    }    /* hash and update */    md2_compress(md);    md2_update_chksum(md);    /* hash checksum */    memcpy(md->md2.buf, md->md2.chksum, 16);    md2_compress(md);    /* output is lower 16 bytes of X */    memcpy(hash, md->md2.X, 16);#ifdef CLEAN_STACK    zeromem(md, sizeof(hash_state));#endif    return CRYPT_OK;}int md2_test(void){ #ifndef LTC_TEST    return CRYPT_NOP; #else       static const struct {        char *msg;        unsigned char md[16];   } tests[] = {      { "",        {0x83,0x50,0xe5,0xa3,0xe2,0x4c,0x15,0x3d,         0xf2,0x27,0x5c,0x9f,0x80,0x69,0x27,0x73        }      },      { "a",        {0x32,0xec,0x01,0xec,0x4a,0x6d,0xac,0x72,         0xc0,0xab,0x96,0xfb,0x34,0xc0,0xb5,0xd1        }      },      { "message digest",        {0xab,0x4f,0x49,0x6b,0xfb,0x2a,0x53,0x0b,         0x21,0x9f,0xf3,0x30,0x31,0xfe,0x06,0xb0        }      },      { "abcdefghijklmnopqrstuvwxyz",        {0x4e,0x8d,0xdf,0xf3,0x65,0x02,0x92,0xab,         0x5a,0x41,0x08,0xc3,0xaa,0x47,0x94,0x0b        }      },      { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",        {0xda,0x33,0xde,0xf2,0xa4,0x2d,0xf1,0x39,         0x75,0x35,0x28,0x46,0xc3,0x03,0x38,0xcd        }      },      { "12345678901234567890123456789012345678901234567890123456789012345678901234567890",        {0xd5,0x97,0x6f,0x79,0xd8,0x3d,0x3a,0x0d,         0xc9,0x80,0x6c,0x3c,0x66,0xf3,0xef,0xd8        }      }   };   int i;   hash_state md;   unsigned char buf[16];   for (i = 0; i < (int)(sizeof(tests) / sizeof(tests[0])); i++) {       md2_init(&md);       md2_process(&md, (unsigned char*)tests[i].msg, (unsigned long)strlen(tests[i].msg));       md2_done(&md, buf);       if (memcmp(buf, tests[i].md, 16) != 0) {          return CRYPT_FAIL_TESTVECTOR;       }   }   return CRYPT_OK;          #endif}#endif