2 // MD2Managed.cs - Message Digest 2 Managed Implementation
5 // Sebastien Pouliot (spouliot@motus.com)
7 // (C) 2001-2003 Motus Technologies Inc. (http://www.motus.com)
12 namespace Mono.Security.Cryptography {
15 // a. RFC1319: The MD2 Message-Digest Algorithm
16 // http://www.ietf.org/rfc/rfc1319.txt
18 public class MD2Managed : MD2 {
21 private byte[] checksum;
22 private byte[] buffer;
26 /// Permutation of 0..255 constructed from the digits of pi. It gives a
27 /// "random" nonlinear byte substitution operation.
29 static private byte[] PI_SUBST = {
30 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
31 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
32 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
33 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
34 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
35 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
36 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
37 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
38 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
39 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
40 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
41 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
42 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
43 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
44 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
45 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
46 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
47 31, 26, 219, 153, 141, 51, 159, 17, 131, 20 };
49 private byte[] Padding (int nLength)
52 byte[] padding = new byte [nLength];
53 for (int i = 0; i < padding.Length; i++)
54 padding[i] = (byte) nLength;
60 //--- constructor -----------------------------------------------------------
62 public MD2Managed () : base ()
64 // we allocate the context memory
65 state = new byte [16];
66 checksum = new byte [16];
67 buffer = new byte [16];
68 // the initialize our context
72 public override void Initialize ()
75 Array.Clear (state, 0, 16);
76 Array.Clear (checksum, 0, 16);
77 Array.Clear (buffer, 0, 16);
80 protected override void HashCore (byte[] array, int ibStart, int cbSize)
84 /* Update number of bytes mod 16 */
86 count = (int) (index + cbSize) & 0xf;
88 int partLen = 16 - index;
90 /* Transform as many times as possible. */
91 if (cbSize >= partLen) {
92 // MD2_memcpy((POINTER)&context->buffer[index], (POINTER)input, partLen);
93 Array.Copy (array, ibStart, buffer, index, partLen);
94 // MD2Transform (context->state, context->checksum, context->buffer);
95 MD2Transform (state, checksum, buffer, 0);
97 for (i = partLen; i + 15 < cbSize; i += 16) {
98 // MD2Transform (context->state, context->checksum, &input[i]);
99 MD2Transform (state, checksum, array, i);
107 /* Buffer remaining input */
108 // MD2_memcpy((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen-i);
109 Array.Copy (array, ibStart + i, buffer, index, (cbSize - i));
112 protected override byte[] HashFinal ()
114 // Pad out to multiple of 16.
116 int padLen = 16 - index;
118 // is padding needed ? required if length not a multiple of 16.
120 HashCore (Padding (padLen), 0, padLen);
122 // Extend with checksum
123 HashCore (checksum, 0, 16);
125 // Store state in digest
126 byte[] digest = (byte[]) state.Clone ();
128 // Zeroize sensitive information.
134 //--- private methods ---------------------------------------------------
137 /// MD2 basic transformation. Transforms state and updates checksum
140 private void MD2Transform (byte[] state, byte[] checksum, byte[] block, int index)
142 byte[] x = new byte [48];
144 /* Form encryption block from state, block, state ^ block. */
145 // MD2_memcpy ((POINTER)x, (POINTER)state, 16);
146 Array.Copy (state, 0, x, 0, 16);
147 // MD2_memcpy ((POINTER)x+16, (POINTER)block, 16);
148 Array.Copy (block, index, x, 16, 16);
150 // for (i = 0; i < 16; i++) x[i+32] = state[i] ^ block[i];
151 for (int i = 0; i < 16; i++)
152 x [i+32] = (byte) ((byte) state [i] ^ (byte) block [index + i]);
154 /* Encrypt block (18 rounds). */
156 for (int i = 0; i < 18; i++) {
157 for (int j = 0; j < 48; j++ )
158 t = x [j] ^= PI_SUBST [t];
163 // MD2_memcpy ((POINTER)state, (POINTER)x, 16);
164 Array.Copy (x, 0, state, 0, 16);
166 /* Update checksum. */
168 for (int i = 0; i < 16; i++)
169 t = checksum [i] ^= PI_SUBST [block [index + i] ^ t];
171 /* Zeroize sensitive information. */
172 // MD2_memset ((POINTER)x, 0, sizeof (x));
173 Array.Clear (x, 0, 48);