4 * Copyright (c) 1999 Pekka Riikonen <priikone@poseidon.pspt.fi>
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish, dis-
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14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
19 * ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
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21 * ITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
25 * Except as contained in this notice, the name of the authors shall
26 * not be used in advertising or otherwise to promote the sale, use or
27 * other dealings in this Software without prior written authorization from
33 * Based on RC5 reference code and on description of Bruce Schneier's
34 * Applied Cryptography.
36 * This implementation has a word size of 32 bits, a rounds of 16 and
37 * variable key length from 128 and 192 up to 256 bits.
41 #include "silcincludes.h"
45 #define RC5E(i, A, B) \
47 A = rotl(A, B) + S[i]; \
49 B = rotl(B, A) + S[i + 1];
52 #define RC5D(i, A, B) \
60 int rc5_set_key(RC5Context *ctx, char *key, int key_len)
62 u32 *in_key = (u32 *)key;
63 u32 i, j, k, A, B, L[c];
64 u32 *out_key = ctx->out_key;
66 if (key_len < b || key_len > (2 * b))
72 for (i = 0; i < key_len / w; i++)
75 /* init key array (S) */
76 out_key[0] = 0xb7e15163;
77 for (i = 1; i < t; i++)
78 out_key[i] = out_key[i - 1] + 0x9e3779b9;
80 /* mix L and key array (S) */
82 for (k = i = j = 0; k < (3 * t); k++) {
83 A = rotl(out_key[i] + (A + B), 3);
85 B = rotl(L[j] + B, B);
95 /* Encrypts *one* block at a time. */
97 int rc5_encrypt(RC5Context *ctx, u32 *in, u32 *out)
100 u32 *S = ctx->out_key;
105 RC5E(2, A, B); RC5E(4, A, B);
106 RC5E(6, A, B); RC5E(8, A, B);
107 RC5E(10, A, B); RC5E(12, A, B);
108 RC5E(14, A, B); RC5E(16, A, B);
109 RC5E(18, A, B); RC5E(20, A, B);
110 RC5E(22, A, B); RC5E(24, A, B);
111 RC5E(26, A, B); RC5E(28, A, B);
112 RC5E(30, A, B); RC5E(32, A, B);
120 /* Decrypts *one* block at a time. */
122 int rc5_decrypt(RC5Context *ctx, u32 *in, u32 *out)
125 u32 *S = ctx->out_key;
130 RC5D(32, A, B); RC5D(30, A, B);
131 RC5D(28, A, B); RC5D(26, A, B);
132 RC5D(24, A, B); RC5D(22, A, B);
133 RC5D(20, A, B); RC5D(18, A, B);
134 RC5D(16, A, B); RC5D(14, A, B);
135 RC5D(12, A, B); RC5D(10, A, B);
136 RC5D(8, A, B); RC5D(6, A, B);
137 RC5D(4, A, B); RC5D(2, A, B);