Annotation of quake2/qcommon/md4.c, revision 1.1.1.1

1.1       root        1: /* GLOBAL.H - RSAREF types and constants */
                      2: 
                      3: #include <string.h>
                      4: 
                      5: /* POINTER defines a generic pointer type */
                      6: typedef unsigned char *POINTER;
                      7: 
                      8: /* UINT2 defines a two byte word */
                      9: typedef unsigned short int UINT2;
                     10: 
                     11: /* UINT4 defines a four byte word */
                     12: typedef unsigned long int UINT4;
                     13: 
                     14:   
                     15: /* MD4.H - header file for MD4C.C */
                     16: 
                     17: /* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. 
                     18: 
                     19: All rights reserved.
                     20:   
                     21: License to copy and use this software is granted provided that it is identified as the �RSA Data Security, Inc. MD4 Message-Digest Algorithm� in all material mentioning or referencing this software or this function.
                     22: License is also granted to make and use derivative works provided that such works are identified as �derived from the RSA Data Security, Inc. MD4 Message-Digest Algorithm� in all material mentioning or referencing the derived work.
                     23: RSA Data Security, Inc. makes no representations concerning either the merchantability of this software or the suitability of this software for any particular purpose. It is provided �as is� without express or implied warranty of any kind.
                     24:   
                     25: These notices must be retained in any copies of any part of this documentation and/or software. */
                     26: 
                     27: /* MD4 context. */
                     28: typedef struct {
                     29:        UINT4 state[4];                         /* state (ABCD) */
                     30:        UINT4 count[2];                         /* number of bits, modulo 2^64 (lsb first) */
                     31:        unsigned char buffer[64];                       /* input buffer */
                     32: } MD4_CTX;
                     33: 
                     34: void MD4Init (MD4_CTX *);
                     35: void MD4Update (MD4_CTX *, unsigned char *, unsigned int);
                     36: void MD4Final (unsigned char [16], MD4_CTX *);
                     37:   
                     38: 
                     39:   
                     40: /* MD4C.C - RSA Data Security, Inc., MD4 message-digest algorithm */
                     41: /* Copyright (C) 1990-2, RSA Data Security, Inc. All rights reserved.
                     42:   
                     43: License to copy and use this software is granted provided that it is identified as the
                     44: RSA Data Security, Inc. MD4 Message-Digest Algorithm
                     45:  in all material mentioning or referencing this software or this function.
                     46: License is also granted to make and use derivative works provided that such works are identified as 
                     47: derived from the RSA Data Security, Inc. MD4 Message-Digest Algorithm
                     48: in all material mentioning or referencing the derived work.
                     49: RSA Data Security, Inc. makes no representations concerning either the merchantability of this software or the suitability of this software for any particular purpose. It is provided
                     50: as is without express or implied warranty of any kind.
                     51:   
                     52: These notices must be retained in any copies of any part of this documentation and/or software. */
                     53: 
                     54: /* Constants for MD4Transform routine.  */
                     55: #define S11 3
                     56: #define S12 7
                     57: #define S13 11
                     58: #define S14 19
                     59: #define S21 3
                     60: #define S22 5
                     61: #define S23 9
                     62: #define S24 13
                     63: #define S31 3
                     64: #define S32 9
                     65: #define S33 11
                     66: #define S34 15
                     67: 
                     68: static void MD4Transform (UINT4 [4], unsigned char [64]);
                     69: static void Encode (unsigned char *, UINT4 *, unsigned int);
                     70: static void Decode (UINT4 *, unsigned char *, unsigned int);
                     71: 
                     72: static unsigned char PADDING[64] = {
                     73: 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
                     74: };
                     75: 
                     76: /* F, G and H are basic MD4 functions. */
                     77: #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
                     78: #define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
                     79: #define H(x, y, z) ((x) ^ (y) ^ (z))
                     80: 
                     81: /* ROTATE_LEFT rotates x left n bits. */
                     82: #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
                     83: 
                     84: /* FF, GG and HH are transformations for rounds 1, 2 and 3 */
                     85: /* Rotation is separate from addition to prevent recomputation */
                     86: #define FF(a, b, c, d, x, s) {(a) += F ((b), (c), (d)) + (x); (a) = ROTATE_LEFT ((a), (s));}
                     87: 
                     88: #define GG(a, b, c, d, x, s) {(a) += G ((b), (c), (d)) + (x) + (UINT4)0x5a827999; (a) = ROTATE_LEFT ((a), (s));}
                     89: 
                     90: #define HH(a, b, c, d, x, s) {(a) += H ((b), (c), (d)) + (x) + (UINT4)0x6ed9eba1; (a) = ROTATE_LEFT ((a), (s));}
                     91: 
                     92: 
                     93: /* MD4 initialization. Begins an MD4 operation, writing a new context. */
                     94: void MD4Init (MD4_CTX *context)
                     95: {
                     96:        context->count[0] = context->count[1] = 0;
                     97: 
                     98: /* Load magic initialization constants.*/
                     99: context->state[0] = 0x67452301;
                    100: context->state[1] = 0xefcdab89;
                    101: context->state[2] = 0x98badcfe;
                    102: context->state[3] = 0x10325476;
                    103: }
                    104: 
                    105: /* MD4 block update operation. Continues an MD4 message-digest operation, processing another message block, and updating the context. */
                    106: void MD4Update (MD4_CTX *context, unsigned char *input, unsigned int inputLen)
                    107: {
                    108:        unsigned int i, index, partLen;
                    109: 
                    110:        /* Compute number of bytes mod 64 */
                    111:        index = (unsigned int)((context->count[0] >> 3) & 0x3F);
                    112: 
                    113:        /* Update number of bits */
                    114:        if ((context->count[0] += ((UINT4)inputLen << 3))< ((UINT4)inputLen << 3))
                    115:                context->count[1]++;
                    116: 
                    117:        context->count[1] += ((UINT4)inputLen >> 29);
                    118: 
                    119:        partLen = 64 - index;
                    120: 
                    121:        /* Transform as many times as possible.*/
                    122:        if (inputLen >= partLen)
                    123:        {
                    124:                memcpy((POINTER)&context->buffer[index], (POINTER)input, partLen);
                    125:                MD4Transform (context->state, context->buffer);
                    126: 
                    127:                for (i = partLen; i + 63 < inputLen; i += 64)
                    128:                        MD4Transform (context->state, &input[i]);
                    129: 
                    130:                index = 0;
                    131:        }
                    132:        else
                    133:                i = 0;
                    134: 
                    135:        /* Buffer remaining input */
                    136:        memcpy ((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen-i);
                    137: }
                    138: 
                    139: 
                    140: /* MD4 finalization. Ends an MD4 message-digest operation, writing the the message digest and zeroizing the context. */
                    141: void MD4Final (unsigned char digest[16], MD4_CTX *context)
                    142: {
                    143:        unsigned char bits[8];
                    144:        unsigned int index, padLen;
                    145: 
                    146:        /* Save number of bits */
                    147:        Encode (bits, context->count, 8);
                    148: 
                    149:        /* Pad out to 56 mod 64.*/
                    150:        index = (unsigned int)((context->count[0] >> 3) & 0x3f);
                    151:        padLen = (index < 56) ? (56 - index) : (120 - index);
                    152:        MD4Update (context, PADDING, padLen);
                    153: 
                    154:        /* Append length (before padding) */
                    155:        MD4Update (context, bits, 8);
                    156:        
                    157:        /* Store state in digest */
                    158:        Encode (digest, context->state, 16);
                    159: 
                    160:        /* Zeroize sensitive information.*/
                    161:        memset ((POINTER)context, 0, sizeof (*context));
                    162: }
                    163: 
                    164: 
                    165: /* MD4 basic transformation. Transforms state based on block. */
                    166: static void MD4Transform (UINT4 state[4], unsigned char block[64])
                    167: {
                    168:        UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
                    169: 
                    170:        Decode (x, block, 64);
                    171: 
                    172: /* Round 1 */
                    173: FF (a, b, c, d, x[ 0], S11);                           /* 1 */
                    174: FF (d, a, b, c, x[ 1], S12);                           /* 2 */
                    175: FF (c, d, a, b, x[ 2], S13);                           /* 3 */
                    176: FF (b, c, d, a, x[ 3], S14);                           /* 4 */
                    177: FF (a, b, c, d, x[ 4], S11);                           /* 5 */
                    178: FF (d, a, b, c, x[ 5], S12);                           /* 6 */
                    179: FF (c, d, a, b, x[ 6], S13);                           /* 7 */
                    180: FF (b, c, d, a, x[ 7], S14);                           /* 8 */
                    181: FF (a, b, c, d, x[ 8], S11);                           /* 9 */
                    182: FF (d, a, b, c, x[ 9], S12);                           /* 10 */
                    183: FF (c, d, a, b, x[10], S13);                   /* 11 */
                    184: FF (b, c, d, a, x[11], S14);                   /* 12 */
                    185: FF (a, b, c, d, x[12], S11);                   /* 13 */
                    186: FF (d, a, b, c, x[13], S12);                   /* 14 */
                    187: FF (c, d, a, b, x[14], S13);                   /* 15 */
                    188: FF (b, c, d, a, x[15], S14);                   /* 16 */
                    189: 
                    190: /* Round 2 */
                    191: GG (a, b, c, d, x[ 0], S21);                   /* 17 */
                    192: GG (d, a, b, c, x[ 4], S22);                   /* 18 */
                    193: GG (c, d, a, b, x[ 8], S23);                   /* 19 */
                    194: GG (b, c, d, a, x[12], S24);                   /* 20 */
                    195: GG (a, b, c, d, x[ 1], S21);                   /* 21 */
                    196: GG (d, a, b, c, x[ 5], S22);                   /* 22 */
                    197: GG (c, d, a, b, x[ 9], S23);                   /* 23 */
                    198: GG (b, c, d, a, x[13], S24);                   /* 24 */
                    199: GG (a, b, c, d, x[ 2], S21);                   /* 25 */
                    200: GG (d, a, b, c, x[ 6], S22);                   /* 26 */
                    201: GG (c, d, a, b, x[10], S23);                   /* 27 */
                    202: GG (b, c, d, a, x[14], S24);                   /* 28 */
                    203: GG (a, b, c, d, x[ 3], S21);                   /* 29 */
                    204: GG (d, a, b, c, x[ 7], S22);                   /* 30 */
                    205: GG (c, d, a, b, x[11], S23);                   /* 31 */
                    206: GG (b, c, d, a, x[15], S24);                   /* 32 */
                    207: 
                    208: /* Round 3 */
                    209: HH (a, b, c, d, x[ 0], S31);                           /* 33 */
                    210: HH (d, a, b, c, x[ 8], S32);                   /* 34 */
                    211: HH (c, d, a, b, x[ 4], S33);                   /* 35 */
                    212: HH (b, c, d, a, x[12], S34);                   /* 36 */
                    213: HH (a, b, c, d, x[ 2], S31);                   /* 37 */
                    214: HH (d, a, b, c, x[10], S32);                   /* 38 */
                    215: HH (c, d, a, b, x[ 6], S33);                   /* 39 */
                    216: HH (b, c, d, a, x[14], S34);                   /* 40 */
                    217: HH (a, b, c, d, x[ 1], S31);                   /* 41 */
                    218: HH (d, a, b, c, x[ 9], S32);                   /* 42 */
                    219: HH (c, d, a, b, x[ 5], S33);                   /* 43 */
                    220: HH (b, c, d, a, x[13], S34);                   /* 44 */
                    221: HH (a, b, c, d, x[ 3], S31);                   /* 45 */
                    222: HH (d, a, b, c, x[11], S32);                   /* 46 */
                    223: HH (c, d, a, b, x[ 7], S33);                   /* 47 */
                    224: HH (b, c, d, a, x[15], S34);                   /* 48 */
                    225: 
                    226: state[0] += a;
                    227: state[1] += b;
                    228: state[2] += c;
                    229: state[3] += d;
                    230: 
                    231:        /* Zeroize sensitive information.*/
                    232:        memset ((POINTER)x, 0, sizeof (x));
                    233: }
                    234: 
                    235: 
                    236: /* Encodes input (UINT4) into output (unsigned char). Assumes len is a multiple of 4. */
                    237: static void Encode (unsigned char *output, UINT4 *input, unsigned int len)
                    238: {
                    239:        unsigned int i, j;
                    240: 
                    241:        for (i = 0, j = 0; j < len; i++, j += 4) {
                    242:                output[j] = (unsigned char)(input[i] & 0xff);
                    243:                output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
                    244:                output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
                    245:                output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
                    246:        }
                    247: }
                    248: 
                    249: 
                    250: /* Decodes input (unsigned char) into output (UINT4). Assumes len is a multiple of 4. */
                    251: static void Decode (UINT4 *output, unsigned char *input, unsigned int len)
                    252: {
                    253: unsigned int i, j;
                    254: 
                    255: for (i = 0, j = 0; j < len; i++, j += 4)
                    256:        output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) | (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
                    257: }
                    258: 
                    259: //===================================================================
                    260: 
                    261: unsigned Com_BlockChecksum (void *buffer, int length)
                    262: {
                    263:        int                     digest[4];
                    264:        unsigned        val;
                    265:        MD4_CTX         ctx;
                    266: 
                    267:        MD4Init (&ctx);
                    268:        MD4Update (&ctx, (unsigned char *)buffer, length);
                    269:        MD4Final ( (unsigned char *)digest, &ctx);
                    270:        
                    271:        val = digest[0] ^ digest[1] ^ digest[2] ^ digest[3];
                    272: 
                    273:        return val;
                    274: }

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