1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10
11 /**
12 @file rc6.c
13 LTC_RC6 code by Tom St Denis
14 */
15 #include "tomcrypt_private.h"
16
17 #ifdef LTC_RC6
18
19 const struct ltc_cipher_descriptor rc6_desc =
20 {
21 "rc6",
22 3,
23 8, 128, 16, 20,
24 &rc6_setup,
25 &rc6_ecb_encrypt,
26 &rc6_ecb_decrypt,
27 &rc6_test,
28 &rc6_done,
29 &rc6_keysize,
30 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
31 };
32
33 static const ulong32 stab[44] = {
34 0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL,
35 0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL,
36 0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL,
37 0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL,
38 0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL,
39 0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL };
40
41 /**
42 Initialize the LTC_RC6 block cipher
43 @param key The symmetric key you wish to pass
44 @param keylen The key length in bytes
45 @param num_rounds The number of rounds desired (0 for default)
46 @param skey The key in as scheduled by this function.
47 @return CRYPT_OK if successful
48 */
49 #ifdef LTC_CLEAN_STACK
_rc6_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)50 static int _rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
51 #else
52 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
53 #endif
54 {
55 ulong32 L[64], S[50], A, B, i, j, v, s, l;
56
57 LTC_ARGCHK(key != NULL);
58 LTC_ARGCHK(skey != NULL);
59
60 /* test parameters */
61 if (num_rounds != 0 && num_rounds != 20) {
62 return CRYPT_INVALID_ROUNDS;
63 }
64
65 /* key must be between 64 and 1024 bits */
66 if (keylen < 8 || keylen > 128) {
67 return CRYPT_INVALID_KEYSIZE;
68 }
69
70 /* copy the key into the L array */
71 for (A = i = j = 0; i < (ulong32)keylen; ) {
72 A = (A << 8) | ((ulong32)(key[i++] & 255));
73 if (!(i & 3)) {
74 L[j++] = BSWAP(A);
75 A = 0;
76 }
77 }
78
79 /* handle odd sized keys */
80 if (keylen & 3) {
81 A <<= (8 * (4 - (keylen&3)));
82 L[j++] = BSWAP(A);
83 }
84
85 /* setup the S array */
86 XMEMCPY(S, stab, 44 * sizeof(stab[0]));
87
88 /* mix buffer */
89 s = 3 * MAX(44, j);
90 l = j;
91 for (A = B = i = j = v = 0; v < s; v++) {
92 A = S[i] = ROLc(S[i] + A + B, 3);
93 B = L[j] = ROL(L[j] + A + B, (A+B));
94 if (++i == 44) { i = 0; }
95 if (++j == l) { j = 0; }
96 }
97
98 /* copy to key */
99 for (i = 0; i < 44; i++) {
100 skey->rc6.K[i] = S[i];
101 }
102 return CRYPT_OK;
103 }
104
105 #ifdef LTC_CLEAN_STACK
rc6_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)106 int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
107 {
108 int x;
109 x = _rc6_setup(key, keylen, num_rounds, skey);
110 burn_stack(sizeof(ulong32) * 122);
111 return x;
112 }
113 #endif
114
115 /**
116 Encrypts a block of text with LTC_RC6
117 @param pt The input plaintext (16 bytes)
118 @param ct The output ciphertext (16 bytes)
119 @param skey The key as scheduled
120 */
121 #ifdef LTC_CLEAN_STACK
_rc6_ecb_encrypt(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)122 static int _rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
123 #else
124 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
125 #endif
126 {
127 ulong32 a,b,c,d,t,u;
128 const ulong32 *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,const symmetric_key * skey)162 int rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const 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 LTC_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,const symmetric_key * skey)177 static int _rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
178 #else
179 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
180 #endif
181 {
182 ulong32 a,b,c,d,t,u;
183 const ulong32 *K;
184 int r;
185
186 LTC_ARGCHK(skey != NULL);
187 LTC_ARGCHK(pt != NULL);
188 LTC_ARGCHK(ct != NULL);
189
190 LOAD32L(a,&ct[0]);LOAD32L(b,&ct[4]);LOAD32L(c,&ct[8]);LOAD32L(d,&ct[12]);
191 a -= skey->rc6.K[42];
192 c -= skey->rc6.K[43];
193
194 #define RND(a,b,c,d) \
195 t = (b * (b + b + 1)); t = ROLc(t, 5); \
196 u = (d * (d + d + 1)); u = ROLc(u, 5); \
197 c = ROR(c - K[1], t) ^ u; \
198 a = ROR(a - K[0], u) ^ t; K -= 2;
199
200 K = skey->rc6.K + 40;
201
202 for (r = 0; r < 20; r += 4) {
203 RND(d,a,b,c);
204 RND(c,d,a,b);
205 RND(b,c,d,a);
206 RND(a,b,c,d);
207 }
208
209 #undef RND
210
211 b -= skey->rc6.K[0];
212 d -= skey->rc6.K[1];
213 STORE32L(a,&pt[0]);STORE32L(b,&pt[4]);STORE32L(c,&pt[8]);STORE32L(d,&pt[12]);
214
215 return CRYPT_OK;
216 }
217
218 #ifdef LTC_CLEAN_STACK
rc6_ecb_decrypt(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)219 int rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
220 {
221 int err = _rc6_ecb_decrypt(ct, pt, skey);
222 burn_stack(sizeof(ulong32) * 6 + sizeof(int));
223 return err;
224 }
225 #endif
226
227 /**
228 Performs a self-test of the LTC_RC6 block cipher
229 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
230 */
rc6_test(void)231 int rc6_test(void)
232 {
233 #ifndef LTC_TEST
234 return CRYPT_NOP;
235 #else
236 static const struct {
237 int keylen;
238 unsigned char key[32], pt[16], ct[16];
239 } tests[] = {
240 {
241 16,
242 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
243 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
244 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
245 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
246 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
247 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
248 { 0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23,
249 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4, 0x3f, 0x18 }
250 },
251 {
252 24,
253 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
254 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
255 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0,
256 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
257 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
258 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
259 { 0x68, 0x83, 0x29, 0xd0, 0x19, 0xe5, 0x05, 0x04,
260 0x1e, 0x52, 0xe9, 0x2a, 0xf9, 0x52, 0x91, 0xd4 }
261 },
262 {
263 32,
264 { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
265 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
266 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0,
267 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe },
268 { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
269 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
270 { 0xc8, 0x24, 0x18, 0x16, 0xf0, 0xd7, 0xe4, 0x89,
271 0x20, 0xad, 0x16, 0xa1, 0x67, 0x4e, 0x5d, 0x48 }
272 }
273 };
274 unsigned char tmp[2][16];
275 int x, y, err;
276 symmetric_key key;
277
278 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
279 /* setup key */
280 if ((err = rc6_setup(tests[x].key, tests[x].keylen, 0, &key)) != CRYPT_OK) {
281 return err;
282 }
283
284 /* encrypt and decrypt */
285 rc6_ecb_encrypt(tests[x].pt, tmp[0], &key);
286 rc6_ecb_decrypt(tmp[0], tmp[1], &key);
287
288 /* compare */
289 if (compare_testvector(tmp[0], 16, tests[x].ct, 16, "RC6 Encrypt", x) ||
290 compare_testvector(tmp[1], 16, tests[x].pt, 16, "RC6 Decrypt", x)) {
291 return CRYPT_FAIL_TESTVECTOR;
292 }
293
294 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
295 for (y = 0; y < 16; y++) tmp[0][y] = 0;
296 for (y = 0; y < 1000; y++) rc6_ecb_encrypt(tmp[0], tmp[0], &key);
297 for (y = 0; y < 1000; y++) rc6_ecb_decrypt(tmp[0], tmp[0], &key);
298 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
299 }
300 return CRYPT_OK;
301 #endif
302 }
303
304 /** Terminate the context
305 @param skey The scheduled key
306 */
rc6_done(symmetric_key * skey)307 void rc6_done(symmetric_key *skey)
308 {
309 LTC_UNUSED_PARAM(skey);
310 }
311
312 /**
313 Gets suitable key size
314 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
315 @return CRYPT_OK if the input key size is acceptable.
316 */
rc6_keysize(int * keysize)317 int rc6_keysize(int *keysize)
318 {
319 LTC_ARGCHK(keysize != NULL);
320 if (*keysize < 8) {
321 return CRYPT_INVALID_KEYSIZE;
322 }
323 if (*keysize > 128) {
324 *keysize = 128;
325 }
326 return CRYPT_OK;
327 }
328
329 #endif /*LTC_RC6*/
330
331
332
333 /* ref: $Format:%D$ */
334 /* git commit: $Format:%H$ */
335 /* commit time: $Format:%ai$ */
336