1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11
12 /**
13 @file rc6.c
14 RC6 code by Tom St Denis
15 */
16 #include "tomcrypt.h"
17
18 #ifdef RC6
19
20 const struct ltc_cipher_descriptor rc6_desc =
21 {
22 "rc6",
23 3,
24 8, 128, 16, 20,
25 &rc6_setup,
26 &rc6_ecb_encrypt,
27 &rc6_ecb_decrypt,
28 &rc6_test,
29 &rc6_done,
30 &rc6_keysize,
31 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
32 };
33
34 static const ulong32 stab[44] = {
35 0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL,
36 0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL,
37 0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL,
38 0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL,
39 0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL,
40 0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL };
41
42 /**
43 Initialize the RC6 block cipher
44 @param key The symmetric key you wish to pass
45 @param keylen The key length in bytes
46 @param num_rounds The number of rounds desired (0 for default)
47 @param skey The key in as scheduled by this function.
48 @return CRYPT_OK if successful
49 */
50 #ifdef LTC_CLEAN_STACK
_rc6_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)51 static int _rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
52 #else
53 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
54 #endif
55 {
56 ulong32 L[64], S[50], A, B, i, j, v, s, l;
57
58 LTC_ARGCHK(key != NULL);
59 LTC_ARGCHK(skey != NULL);
60
61 /* test parameters */
62 if (num_rounds != 0 && num_rounds != 20) {
63 return CRYPT_INVALID_ROUNDS;
64 }
65
66 /* key must be between 64 and 1024 bits */
67 if (keylen < 8 || keylen > 128) {
68 return CRYPT_INVALID_KEYSIZE;
69 }
70
71 /* copy the key into the L array */
72 for (A = i = j = 0; i < (ulong32)keylen; ) {
73 A = (A << 8) | ((ulong32)(key[i++] & 255));
74 if (!(i & 3)) {
75 L[j++] = BSWAP(A);
76 A = 0;
77 }
78 }
79
80 /* handle odd sized keys */
81 if (keylen & 3) {
82 A <<= (8 * (4 - (keylen&3)));
83 L[j++] = BSWAP(A);
84 }
85
86 /* setup the S array */
87 XMEMCPY(S, stab, 44 * sizeof(stab[0]));
88
89 /* mix buffer */
90 s = 3 * MAX(44, j);
91 l = j;
92 for (A = B = i = j = v = 0; v < s; v++) {
93 A = S[i] = ROLc(S[i] + A + B, 3);
94 B = L[j] = ROL(L[j] + A + B, (A+B));
95 if (++i == 44) { i = 0; }
96 if (++j == l) { j = 0; }
97 }
98
99 /* copy to key */
100 for (i = 0; i < 44; i++) {
101 skey->rc6.K[i] = S[i];
102 }
103 return CRYPT_OK;
104 }
105
106 #ifdef LTC_CLEAN_STACK
rc6_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)107 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
108 {
109 int x;
110 x = _rc6_setup(key, keylen, num_rounds, skey);
111 burn_stack(sizeof(ulong32) * 122);
112 return x;
113 }
114 #endif
115
116 /**
117 Encrypts a block of text with RC6
118 @param pt The input plaintext (16 bytes)
119 @param ct The output ciphertext (16 bytes)
120 @param skey The key as scheduled
121 */
122 #ifdef LTC_CLEAN_STACK
_rc6_ecb_encrypt(const unsigned char * pt,unsigned char * ct,symmetric_key * skey)123 static int _rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
124 #else
125 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
126 #endif
127 {
128 ulong32 a,b,c,d,t,u, *K;
129 int r;
130
131 LTC_ARGCHK(skey != NULL);
132 LTC_ARGCHK(pt != NULL);
133 LTC_ARGCHK(ct != NULL);
134 LOAD32L(a,&pt[0]);LOAD32L(b,&pt[4]);LOAD32L(c,&pt[8]);LOAD32L(d,&pt[12]);
135
136 b += skey->rc6.K[0];
137 d += skey->rc6.K[1];
138
139 #define RND(a,b,c,d) \
140 t = (b * (b + b + 1)); t = ROLc(t, 5); \
141 u = (d * (d + d + 1)); u = ROLc(u, 5); \
142 a = ROL(a^t,u) + K[0]; \
143 c = ROL(c^u,t) + K[1]; K += 2;
144
145 K = skey->rc6.K + 2;
146 for (r = 0; r < 20; r += 4) {
147 RND(a,b,c,d);
148 RND(b,c,d,a);
149 RND(c,d,a,b);
150 RND(d,a,b,c);
151 }
152
153 #undef RND
154
155 a += skey->rc6.K[42];
156 c += skey->rc6.K[43];
157 STORE32L(a,&ct[0]);STORE32L(b,&ct[4]);STORE32L(c,&ct[8]);STORE32L(d,&ct[12]);
158 return CRYPT_OK;
159 }
160
161 #ifdef LTC_CLEAN_STACK
rc6_ecb_encrypt(const unsigned char * pt,unsigned char * ct,symmetric_key * skey)162 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
163 {
164 int err = _rc6_ecb_encrypt(pt, ct, skey);
165 burn_stack(sizeof(ulong32) * 6 + sizeof(int));
166 return err;
167 }
168 #endif
169
170 /**
171 Decrypts a block of text with RC6
172 @param ct The input ciphertext (16 bytes)
173 @param pt The output plaintext (16 bytes)
174 @param skey The key as scheduled
175 */
176 #ifdef LTC_CLEAN_STACK
_rc6_ecb_decrypt(const unsigned char * ct,unsigned char * pt,symmetric_key * skey)177 static int _rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
178 #else
179 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
180 #endif
181 {
182 ulong32 a,b,c,d,t,u, *K;
183 int r;
184
185 LTC_ARGCHK(skey != NULL);
186 LTC_ARGCHK(pt != NULL);
187 LTC_ARGCHK(ct != NULL);
188
189 LOAD32L(a,&ct[0]);LOAD32L(b,&ct[4]);LOAD32L(c,&ct[8]);LOAD32L(d,&ct[12]);
190 a -= skey->rc6.K[42];
191 c -= skey->rc6.K[43];
192
193 #define RND(a,b,c,d) \
194 t = (b * (b + b + 1)); t = ROLc(t, 5); \
195 u = (d * (d + d + 1)); u = ROLc(u, 5); \
196 c = ROR(c - K[1], t) ^ u; \
197 a = ROR(a - K[0], u) ^ t; K -= 2;
198
199 K = skey->rc6.K + 40;
200
201 for (r = 0; r < 20; r += 4) {
202 RND(d,a,b,c);
203 RND(c,d,a,b);
204 RND(b,c,d,a);
205 RND(a,b,c,d);
206 }
207
208 #undef RND
209
210 b -= skey->rc6.K[0];
211 d -= skey->rc6.K[1];
212 STORE32L(a,&pt[0]);STORE32L(b,&pt[4]);STORE32L(c,&pt[8]);STORE32L(d,&pt[12]);
213
214 return CRYPT_OK;
215 }
216
217 #ifdef LTC_CLEAN_STACK
rc6_ecb_decrypt(const unsigned char * ct,unsigned char * pt,symmetric_key * skey)218 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
219 {
220 int err = _rc6_ecb_decrypt(ct, pt, skey);
221 burn_stack(sizeof(ulong32) * 6 + sizeof(int));
222 return err;
223 }
224 #endif
225
226 /**
227 Performs a self-test of the RC6 block cipher
228 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
229 */
rc6_test(void)230 int rc6_test(void)
231 {
232 #ifndef LTC_TEST
233 return CRYPT_NOP;
234 #else
235 static const struct {
236 int keylen;
237 unsigned char key[32], pt[16], ct[16];
238 } tests[] = {
239 {
240 16,
241 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
242 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
243 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
244 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
245 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
246 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
247 { 0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23,
248 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4, 0x3f, 0x18 }
249 },
250 {
251 24,
252 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
253 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
254 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0,
255 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
256 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
257 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
258 { 0x68, 0x83, 0x29, 0xd0, 0x19, 0xe5, 0x05, 0x04,
259 0x1e, 0x52, 0xe9, 0x2a, 0xf9, 0x52, 0x91, 0xd4 }
260 },
261 {
262 32,
263 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
264 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
265 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0,
266 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe },
267 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
268 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
269 { 0xc8, 0x24, 0x18, 0x16, 0xf0, 0xd7, 0xe4, 0x89,
270 0x20, 0xad, 0x16, 0xa1, 0x67, 0x4e, 0x5d, 0x48 }
271 }
272 };
273 unsigned char tmp[2][16];
274 int x, y, err;
275 symmetric_key key;
276
277 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
278 /* setup key */
279 if ((err = rc6_setup(tests[x].key, tests[x].keylen, 0, &key)) != CRYPT_OK) {
280 return err;
281 }
282
283 /* encrypt and decrypt */
284 rc6_ecb_encrypt(tests[x].pt, tmp[0], &key);
285 rc6_ecb_decrypt(tmp[0], tmp[1], &key);
286
287 /* compare */
288 if (XMEMCMP(tmp[0], tests[x].ct, 16) || XMEMCMP(tmp[1], tests[x].pt, 16)) {
289 #if 0
290 printf("\n\nFailed test %d\n", x);
291 if (XMEMCMP(tmp[0], tests[x].ct, 16)) {
292 printf("Ciphertext: ");
293 for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]);
294 printf("\nExpected : ");
295 for (y = 0; y < 16; y++) printf("%02x ", tests[x].ct[y]);
296 printf("\n");
297 }
298 if (XMEMCMP(tmp[1], tests[x].pt, 16)) {
299 printf("Plaintext: ");
300 for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]);
301 printf("\nExpected : ");
302 for (y = 0; y < 16; y++) printf("%02x ", tests[x].pt[y]);
303 printf("\n");
304 }
305 #endif
306 return CRYPT_FAIL_TESTVECTOR;
307 }
308
309 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
310 for (y = 0; y < 16; y++) tmp[0][y] = 0;
311 for (y = 0; y < 1000; y++) rc6_ecb_encrypt(tmp[0], tmp[0], &key);
312 for (y = 0; y < 1000; y++) rc6_ecb_decrypt(tmp[0], tmp[0], &key);
313 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
314 }
315 return CRYPT_OK;
316 #endif
317 }
318
319 /** Terminate the context
320 @param skey The scheduled key
321 */
rc6_done(symmetric_key * skey)322 void rc6_done(symmetric_key *skey)
323 {
324 }
325
326 /**
327 Gets suitable key size
328 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
329 @return CRYPT_OK if the input key size is acceptable.
330 */
rc6_keysize(int * keysize)331 int rc6_keysize(int *keysize)
332 {
333 LTC_ARGCHK(keysize != NULL);
334 if (*keysize < 8) {
335 return CRYPT_INVALID_KEYSIZE;
336 } else if (*keysize > 128) {
337 *keysize = 128;
338 }
339 return CRYPT_OK;
340 }
341
342 #endif /*RC6*/
343
344
345
346 /* $Source: /cvs/libtom/libtomcrypt/src/ciphers/rc6.c,v $ */
347 /* $Revision: 1.12 $ */
348 /* $Date: 2006/11/08 23:01:06 $ */
349