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1.1 root 1: /* MD2C.C - RSA Data Security, Inc., MD2 message-digest algorithm
2: */
3:
4: /* Copyright (C) 1990, RSA Data Security, Inc. All rights reserved.
5:
6: License to copy and use this software is granted for
7: non-commercial Internet Privacy-Enhanced Mail provided that it is
8: identified as the "RSA Data Security, Inc. MD2 Message Digest
9: Algorithm" in all material mentioning or referencing this software
10: or this function.
11:
12: RSA Data Security, Inc. makes no representations concerning either
13: the merchantability of this software or the suitability of this
14: software for any particular purpose. It is provided "as is"
15: without express or implied warranty of any kind.
16:
17: These notices must be retained in any copies of any part of this
18: documentation and/or software.
19: */
20:
21: #include "global.h"
22: #include "md2.h"
23:
24: static void MD2Transform PROTO_LIST
25: ((unsigned char [16], unsigned char [16], unsigned char [16]));
26: static void MD2_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int));
27: static void MD2_memset PROTO_LIST ((POINTER, int, unsigned int));
28:
29: /* Permutation of 0..255 constructed from the digits of pi. It gives a
30: "random" nonlinear byte substitution operation.
31: */
32: static unsigned char PI_SUBST[256] = {
33: 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
34: 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
35: 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
36: 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
37: 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
38: 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
39: 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
40: 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
41: 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
42: 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
43: 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
44: 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
45: 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
46: 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
47: 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
48: 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
49: 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
50: 31, 26, 219, 153, 141, 51, 159, 17, 131, 20
51: };
52:
53: static unsigned char *PADDING[] = {
54: (unsigned char *)"", (unsigned char *)"\001", (unsigned char *)"\002\002",
55: (unsigned char *)"\003\003\003", (unsigned char *)"\004\004\004\004",
56: (unsigned char *)"\005\005\005\005\005",
57: (unsigned char *)"\006\006\006\006\006\006",
58: (unsigned char *)"\007\007\007\007\007\007\007",
59: (unsigned char *)"\010\010\010\010\010\010\010\010",
60: (unsigned char *)"\011\011\011\011\011\011\011\011\011",
61: (unsigned char *)"\012\012\012\012\012\012\012\012\012\012",
62: (unsigned char *)"\013\013\013\013\013\013\013\013\013\013\013",
63: (unsigned char *)"\014\014\014\014\014\014\014\014\014\014\014\014",
64: (unsigned char *)"\015\015\015\015\015\015\015\015\015\015\015\015\015",
65: (unsigned char *)"\016\016\016\016\016\016\016\016\016\016\016\016\016\016",
66: (unsigned char *)
67: "\017\017\017\017\017\017\017\017\017\017\017\017\017\017\017",
68: (unsigned char *)
69: "\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020"
70: };
71:
72: /* MD2 initialization. Begins an MD2 operation, writing a new context.
73: */
74: void MD2Init (context)
75: MD2_CTX *context; /* context */
76: {
77: context->count = 0;
78: MD2_memset ((POINTER)context->state, 0, sizeof (context->state));
79: MD2_memset ((POINTER)context->checksum, 0, sizeof (context->checksum));
80: }
81:
82: /* MD2 block update operation. Continues an MD2 message-digest operation,
83: processing another message block, and updating the context.
84: */
85: void MD2Update (context, input, inputLen)
86: MD2_CTX *context; /* context */
87: unsigned char *input; /* input block */
88: unsigned int inputLen; /* length of input block */
89: {
90: unsigned int i, index, partLen;
91:
92: /* Update number of bytes mod 16 */
93: index = context->count;
94: context->count = (index + inputLen) & 0xf;
95:
96: partLen = 16 - index;
97:
98: /* Transform as many times as possible.
99: */
100: if (inputLen >= partLen) {
101: MD2_memcpy ((POINTER)&context->buffer[index], (POINTER)input, partLen);
102: MD2Transform (context->state, context->checksum, context->buffer);
103:
104: for (i = partLen; i + 15 < inputLen; i += 16)
105: MD2Transform (context->state, context->checksum, &input[i]);
106:
107: index = 0;
108: }
109: else
110: i = 0;
111:
112: /* Buffer remaining input */
113: MD2_memcpy
114: ((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen-i);
115: }
116:
117: /* MD2 finalization. Ends an MD2 message-digest operation, writing the
118: message digest and zeroizing the context.
119: */
120: void MD2Final (digest, context)
121: unsigned char digest[16]; /* message digest */
122: MD2_CTX *context; /* context */
123: {
124: unsigned int index, padLen;
125:
126: /* Pad out to multiple of 16.
127: */
128: index = context->count;
129: padLen = 16 - index;
130: MD2Update (context, PADDING[padLen], padLen);
131:
132: /* Extend with checksum */
133: MD2Update (context, context->checksum, 16);
134:
135: /* Store state in digest */
136: MD2_memcpy ((POINTER)digest, (POINTER)context->state, 16);
137:
138: /* Zeroize sensitive information.
139: */
140: MD2_memset ((POINTER)context, 0, sizeof (*context));
141: }
142:
143: /* MD2 basic transformation. Transforms state and updates checksum
144: based on block.
145: */
146: static void MD2Transform (state, checksum, block)
147: unsigned char state[16];
148: unsigned char checksum[16];
149: unsigned char block[16];
150: {
151: unsigned int i, j, t;
152: unsigned char x[48];
153:
154: /* Form encryption block from state, block, state ^ block.
155: */
156: for (i = 0; i < 16; i++) {
157: x[i] = state[i];
158: x[i+16] = block[i];
159: x[i+32] = state[i] ^ block[i];
160: }
161:
162: /* Encrypt block (18 rounds).
163: */
164: t = 0;
165: for (i = 0; i < 18; i++) {
166: for (j = 0; j < 48; j++)
167: t = x[j] ^= PI_SUBST[t];
168: t = (t + i) & 0xff;
169: }
170:
171: /* Save new state */
172: for (i = 0; i < 16; i++)
173: state[i] = x[i];
174:
175: /* Update checksum.
176: */
177: t = checksum[15];
178: for (i = 0; i < 16; i++)
179: t = checksum[i] ^= PI_SUBST[block[i] ^ t];
180:
181: /* Zeroize sensitive information.
182: */
183: MD2_memset ((POINTER)x, 0, sizeof (x));
184: }
185:
186: /* Note: Replace "for loop" with standard memcpy if possible.
187: */
188: static void MD2_memcpy (output, input, len)
189: POINTER output;
190: POINTER input;
191: unsigned int len;
192: {
193: unsigned int i;
194:
195: for (i = 0; i < len; i++)
196: output[i] = input[i];
197: }
198:
199: /* Note: Replace "for loop" with standard memset if possible.
200: */
201: static void MD2_memset (output, value, len)
202: POINTER output;
203: int value;
204: unsigned int len;
205: {
206: unsigned int i;
207:
208: for (i = 0; i < len; i++)
209: ((char *)output)[i] = (char)value;
210: }
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