Annotation of rsaref/source/md5c.c, revision 1.1

1.1     ! root        1: /* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
        !             2:  */
        !             3: 
        !             4: /* Copyright (C) 1991, RSA Data Security, Inc. All rights reserved.
        !             5: 
        !             6:    License to copy and use this software is granted provided that it
        !             7:    is identified as the "RSA Data Security, Inc. MD5 Message-Digest
        !             8:    Algorithm" in all material mentioning or referencing this software
        !             9:    or this function.
        !            10: 
        !            11:    License is also granted to make and use derivative works provided
        !            12:    that such works are identified as "derived from the RSA Data
        !            13:    Security, Inc. MD5 Message-Digest Algorithm" in all material
        !            14:    mentioning or referencing the derived work.  
        !            15:                                                                     
        !            16:    RSA Data Security, Inc. makes no representations concerning either
        !            17:    the merchantability of this software or the suitability of this
        !            18:    software for any particular purpose. It is provided "as is"
        !            19:    without express or implied warranty of any kind.  
        !            20:                                                                     
        !            21:    These notices must be retained in any copies of any part of this
        !            22:    documentation and/or software.  
        !            23:  */
        !            24: 
        !            25: #include "global.h"
        !            26: #include "md5.h"
        !            27: 
        !            28: /* Constants for MD5Transform routine.
        !            29:  */
        !            30: #define S11 7
        !            31: #define S12 12
        !            32: #define S13 17
        !            33: #define S14 22
        !            34: #define S21 5
        !            35: #define S22 9
        !            36: #define S23 14
        !            37: #define S24 20
        !            38: #define S31 4
        !            39: #define S32 11
        !            40: #define S33 16
        !            41: #define S34 23
        !            42: #define S41 6
        !            43: #define S42 10
        !            44: #define S43 15
        !            45: #define S44 21
        !            46: 
        !            47: static void MD5Transform PROTO_LIST ((UINT4 [4], unsigned char [64]));
        !            48: static void Encode PROTO_LIST ((unsigned char *, UINT4 *, unsigned int));
        !            49: static void Decode PROTO_LIST ((UINT4 *, unsigned char *, unsigned int));
        !            50: static void MD5_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int));
        !            51: static void MD5_memset PROTO_LIST ((POINTER, int, unsigned int));
        !            52: 
        !            53: static unsigned char PADDING[64] = {
        !            54:   0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        !            55:   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        !            56:   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
        !            57: };
        !            58: 
        !            59: /* F, G, H and I are basic MD5 functions.
        !            60:  */
        !            61: #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
        !            62: #define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
        !            63: #define H(x, y, z) ((x) ^ (y) ^ (z))
        !            64: #define I(x, y, z) ((y) ^ ((x) | (~z)))
        !            65: 
        !            66: /* ROTATE_LEFT rotates x left n bits.
        !            67:  */
        !            68: #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
        !            69: 
        !            70: /* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
        !            71:    Rotation is separate from addition to prevent recomputation.
        !            72:  */
        !            73: #define FF(a, b, c, d, x, s, ac) { \
        !            74:     (a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
        !            75:     (a) = ROTATE_LEFT ((a), (s)); \
        !            76:     (a) += (b); \
        !            77:   }
        !            78: #define GG(a, b, c, d, x, s, ac) { \
        !            79:     (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
        !            80:     (a) = ROTATE_LEFT ((a), (s)); \
        !            81:     (a) += (b); \
        !            82:   }
        !            83: #define HH(a, b, c, d, x, s, ac) { \
        !            84:     (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
        !            85:     (a) = ROTATE_LEFT ((a), (s)); \
        !            86:     (a) += (b); \
        !            87:   }
        !            88: #define II(a, b, c, d, x, s, ac) { \
        !            89:     (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
        !            90:     (a) = ROTATE_LEFT ((a), (s)); \
        !            91:     (a) += (b); \
        !            92:   }
        !            93: 
        !            94: /* MD5 initialization. Begins an MD5 operation, writing a new context.
        !            95:  */
        !            96: void MD5Init (context)
        !            97: MD5_CTX *context;                                                /* context */
        !            98: {
        !            99:   context->count[0] = context->count[1] = 0;
        !           100: 
        !           101:   /* Load magic initialization constants.
        !           102:    */
        !           103:   context->state[0] = 0x67452301;
        !           104:   context->state[1] = 0xefcdab89;
        !           105:   context->state[2] = 0x98badcfe;
        !           106:   context->state[3] = 0x10325476;
        !           107: }
        !           108: 
        !           109: /* MD5 block update operation. Continues an MD5 message-digest operation,
        !           110:      processing another message block, and updating the context.
        !           111:  */
        !           112: void MD5Update (context, input, inputLen)
        !           113: MD5_CTX *context;                                                /* context */
        !           114: unsigned char *input;                                        /* input block */
        !           115: unsigned int inputLen;                             /* length of input block */
        !           116: {
        !           117:   unsigned int i, index, partLen;
        !           118: 
        !           119:   /* Compute number of bytes mod 64 */
        !           120:   index = (unsigned int)((context->count[0] >> 3) & 0x3F);
        !           121: 
        !           122:   /* Update number of bits */
        !           123:   if ((context->count[0] += ((UINT4)inputLen << 3)) < ((UINT4)inputLen << 3))
        !           124:     context->count[1]++;
        !           125:   context->count[1] += ((UINT4)inputLen >> 29);
        !           126:   
        !           127:   partLen = 64 - index;
        !           128:   
        !           129:   /* Transform as many times as possible.
        !           130:    */
        !           131:   if (inputLen >= partLen) {
        !           132:     MD5_memcpy ((POINTER)&context->buffer[index], (POINTER)input, partLen);
        !           133:     MD5Transform (context->state, context->buffer);
        !           134:   
        !           135:     for (i = partLen; i + 63 < inputLen; i += 64)
        !           136:       MD5Transform (context->state, &input[i]);
        !           137:     
        !           138:     index = 0;
        !           139:   }
        !           140:   else
        !           141:     i = 0;
        !           142:   
        !           143:   /* Buffer remaining input */
        !           144:   MD5_memcpy 
        !           145:     ((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen-i);
        !           146: }
        !           147: 
        !           148: /* MD5 finalization. Ends an MD5 message-digest operation, writing the
        !           149:      the message digest and zeroizing the context.
        !           150:  */
        !           151: void MD5Final (digest, context)
        !           152: unsigned char digest[16];                                 /* message digest */
        !           153: MD5_CTX *context;                                                /* context */
        !           154: {
        !           155:   unsigned char bits[8];
        !           156:   unsigned int index, padLen;
        !           157: 
        !           158:   /* Save number of bits */
        !           159:   Encode (bits, context->count, 8);
        !           160: 
        !           161:   /* Pad out to 56 mod 64.
        !           162:    */
        !           163:   index = (unsigned int)((context->count[0] >> 3) & 0x3f);
        !           164:   padLen = (index < 56) ? (56 - index) : (120 - index);
        !           165:   MD5Update (context, PADDING, padLen);
        !           166:   
        !           167:   /* Append length (before padding) */
        !           168:   MD5Update (context, bits, 8);
        !           169: 
        !           170:   /* Store state in digest */
        !           171:   Encode (digest, context->state, 16);
        !           172:   
        !           173:   /* Zeroize sensitive information.
        !           174:    */
        !           175:   MD5_memset ((POINTER)context, 0, sizeof (*context));
        !           176: }
        !           177: 
        !           178: /* MD5 basic transformation. Transforms state based on block.
        !           179:  */
        !           180: static void MD5Transform (state, block)
        !           181: UINT4 state[4];
        !           182: unsigned char block[64];
        !           183: {
        !           184:   UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
        !           185:   
        !           186:   Decode (x, block, 64);
        !           187: 
        !           188:   /* Round 1 */
        !           189:   FF ( a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
        !           190:   FF ( d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
        !           191:   FF ( c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
        !           192:   FF ( b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
        !           193:   FF ( a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
        !           194:   FF ( d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
        !           195:   FF ( c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
        !           196:   FF ( b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
        !           197:   FF ( a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
        !           198:   FF ( d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
        !           199:   FF ( c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
        !           200:   FF ( b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
        !           201:   FF ( a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
        !           202:   FF ( d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
        !           203:   FF ( c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
        !           204:   FF ( b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
        !           205: 
        !           206:   /* Round 2 */
        !           207:   GG ( a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
        !           208:   GG ( d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
        !           209:   GG ( c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
        !           210:   GG ( b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
        !           211:   GG ( a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
        !           212:   GG ( d, a, b, c, x[10], S22,  0x2441453); /* 22 */
        !           213:   GG ( c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
        !           214:   GG ( b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
        !           215:   GG ( a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
        !           216:   GG ( d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
        !           217:   GG ( c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
        !           218:   GG ( b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
        !           219:   GG ( a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
        !           220:   GG ( d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
        !           221:   GG ( c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
        !           222:   GG ( b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
        !           223: 
        !           224:   /* Round 3 */
        !           225:   HH ( a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
        !           226:   HH ( d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
        !           227:   HH ( c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
        !           228:   HH ( b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
        !           229:   HH ( a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
        !           230:   HH ( d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
        !           231:   HH ( c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
        !           232:   HH ( b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
        !           233:   HH ( a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
        !           234:   HH ( d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
        !           235:   HH ( c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
        !           236:   HH ( b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
        !           237:   HH ( a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
        !           238:   HH ( d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
        !           239:   HH ( c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
        !           240:   HH ( b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
        !           241: 
        !           242:   /* Round 4 */
        !           243:   II ( a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
        !           244:   II ( d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
        !           245:   II ( c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
        !           246:   II ( b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
        !           247:   II ( a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
        !           248:   II ( d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
        !           249:   II ( c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
        !           250:   II ( b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
        !           251:   II ( a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
        !           252:   II ( d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
        !           253:   II ( c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
        !           254:   II ( b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
        !           255:   II ( a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
        !           256:   II ( d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
        !           257:   II ( c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
        !           258:   II ( b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
        !           259: 
        !           260:   state[0] += a;
        !           261:   state[1] += b;
        !           262:   state[2] += c;
        !           263:   state[3] += d;
        !           264:   
        !           265:   /* Zeroize sensitive information.
        !           266:    */
        !           267:   MD5_memset ((POINTER)x, 0, sizeof (x));
        !           268: }
        !           269: 
        !           270: /* Encodes input (UINT4) into output (unsigned char). Assumes len is
        !           271:      a multiple of 4.
        !           272:  */
        !           273: static void Encode (output, input, len)
        !           274: unsigned char *output;
        !           275: UINT4 *input;
        !           276: unsigned int len;
        !           277: {
        !           278:   unsigned int i, j;
        !           279: 
        !           280:   for (i = 0, j = 0; j < len; i++, j += 4) {
        !           281:     output[j] = (unsigned char)(input[i] & 0xff);
        !           282:     output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
        !           283:     output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
        !           284:     output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
        !           285:   }
        !           286: }
        !           287: 
        !           288: /* Decodes input (unsigned char) into output (UINT4). Assumes len is
        !           289:      a multiple of 4.
        !           290:  */
        !           291: static void Decode (output, input, len)
        !           292: UINT4 *output;
        !           293: unsigned char *input;
        !           294: unsigned int len;
        !           295: {
        !           296:   unsigned int i, j;
        !           297: 
        !           298:   for (i = 0, j = 0; j < len; i++, j += 4)
        !           299:     output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
        !           300:       (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
        !           301: }
        !           302: 
        !           303: /* Note: Replace "for loop" with standard memcpy if possible.
        !           304:  */
        !           305: static void MD5_memcpy (output, input, len)
        !           306: POINTER output;
        !           307: POINTER input;
        !           308: unsigned int len;
        !           309: {
        !           310:   unsigned int i;
        !           311:   
        !           312:   for (i = 0; i < len; i++)
        !           313:     output[i] = input[i];
        !           314: }
        !           315: 
        !           316: /* Note: Replace "for loop" with standard memset if possible.
        !           317:  */
        !           318: static void MD5_memset (output, value, len)
        !           319: POINTER output;
        !           320: int value;
        !           321: unsigned int len;
        !           322: {
        !           323:   unsigned int i;
        !           324:   
        !           325:   for (i = 0; i < len; i++)
        !           326:     ((char *)output)[i] = (char)value;
        !           327: }

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