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.
42 #include "rc5_internal.h"
46 * SILC Crypto API for RC5
49 /* Sets the key for the cipher. */
51 SILC_CIPHER_API_SET_KEY(rc5)
55 SILC_GET_WORD_KEY(key, k, keylen);
56 rc5_set_key((RC5Context *)context, k, keylen);
61 /* Sets the string as a new key for the cipher. The string is first
62 hashed and then used as a new key. */
64 SILC_CIPHER_API_SET_KEY_WITH_STRING(rc5)
69 /* Returns the size of the cipher context. */
71 SILC_CIPHER_API_CONTEXT_LEN(rc5)
73 return sizeof(RC5Context);
76 /* Encrypts with the cipher in CBC mode. Source and destination buffers
77 maybe one and same. */
79 SILC_CIPHER_API_ENCRYPT_CBC(rc5)
84 SILC_CBC_GET_IV(tiv, iv);
86 SILC_CBC_ENC_PRE(tiv, src);
87 rc5_encrypt((RC5Context *)context, tiv, tiv);
88 SILC_CBC_ENC_POST(tiv, dst, src);
90 for (i = 16; i < len; i += 16) {
91 SILC_CBC_ENC_PRE(tiv, src);
92 rc5_encrypt((RC5Context *)context, tiv, tiv);
93 SILC_CBC_ENC_POST(tiv, dst, src);
96 SILC_CBC_PUT_IV(tiv, iv);
101 /* Decrypts with the cipher in CBC mode. Source and destination buffers
102 maybe one and same. */
104 SILC_CIPHER_API_DECRYPT_CBC(rc5)
106 SilcUInt32 tmp[4], tmp2[4], tiv[4];
109 SILC_CBC_GET_IV(tiv, iv);
111 SILC_CBC_DEC_PRE(tmp, src);
112 rc5_decrypt((RC5Context *)context, tmp, tmp2);
113 SILC_CBC_DEC_POST(tmp2, dst, src, tmp, tiv);
115 for (i = 16; i < len; i += 16) {
116 SILC_CBC_DEC_PRE(tmp, src);
117 rc5_decrypt((RC5Context *)context, tmp, tmp2);
118 SILC_CBC_DEC_POST(tmp2, dst, src, tmp, tiv);
121 SILC_CBC_PUT_IV(tiv, iv);
127 #define RC5E(i, A, B) \
129 A = rotl(A, B) + S[i]; \
131 B = rotl(B, A) + S[i + 1];
134 #define RC5D(i, A, B) \
136 B = rotr(B, A) ^ A; \
142 int rc5_set_key(RC5Context *ctx, const SilcUInt32 in_key[], int key_len)
144 u32 i, j, k, A, B, L[c];
145 u32 *out_key = ctx->out_key;
147 if (key_len < b || key_len > (2 * b))
151 for (i = 0; i < key_len / w; i++)
154 /* init key array (S) */
155 out_key[0] = 0xb7e15163;
156 for (i = 1; i < t; i++)
157 out_key[i] = out_key[i - 1] + 0x9e3779b9;
159 /* mix L and key array (S) */
161 for (k = i = j = 0; k < (3 * t); k++) {
162 A = rotl(out_key[i] + (A + B), 3);
164 B = rotl(L[j] + B, B);
174 /* Encrypts *one* block at a time. */
176 int rc5_encrypt(RC5Context *ctx, u32 *in, u32 *out)
179 u32 *S = ctx->out_key;
184 RC5E(2, A, B); RC5E(4, A, B);
185 RC5E(6, A, B); RC5E(8, A, B);
186 RC5E(10, A, B); RC5E(12, A, B);
187 RC5E(14, A, B); RC5E(16, A, B);
188 RC5E(18, A, B); RC5E(20, A, B);
189 RC5E(22, A, B); RC5E(24, A, B);
190 RC5E(26, A, B); RC5E(28, A, B);
191 RC5E(30, A, B); RC5E(32, A, B);
199 /* Decrypts *one* block at a time. */
201 int rc5_decrypt(RC5Context *ctx, u32 *in, u32 *out)
204 u32 *S = ctx->out_key;
209 RC5D(32, A, B); RC5D(30, A, B);
210 RC5D(28, A, B); RC5D(26, A, B);
211 RC5D(24, A, B); RC5D(22, A, B);
212 RC5D(20, A, B); RC5D(18, A, B);
213 RC5D(16, A, B); RC5D(14, A, B);
214 RC5D(12, A, B); RC5D(10, A, B);
215 RC5D(8, A, B); RC5D(6, A, B);
216 RC5D(4, A, B); RC5D(2, A, B);