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 rc5.c
13 LTC_RC5 code by Tom St Denis
14 */
15
16 #include "tomcrypt_private.h"
17
18 #ifdef LTC_RC5
19
20 const struct ltc_cipher_descriptor rc5_desc =
21 {
22 "rc5",
23 2,
24 8, 128, 8, 12,
25 &rc5_setup,
26 &rc5_ecb_encrypt,
27 &rc5_ecb_decrypt,
28 &rc5_test,
29 &rc5_done,
30 &rc5_keysize,
31 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
32 };
33
34 static const ulong32 stab[50] = {
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, 0xe96a3d2fUL, 0x87a1b6e8UL, 0x25d930a1UL, 0xc410aa5aUL,
41 0x62482413UL, 0x007f9dccUL
42 };
43
44 /**
45 Initialize the LTC_RC5 block cipher
46 @param key The symmetric key you wish to pass
47 @param keylen The key length in bytes
48 @param num_rounds The number of rounds desired (0 for default)
49 @param skey The key in as scheduled by this function.
50 @return CRYPT_OK if successful
51 */
52 #ifdef LTC_CLEAN_STACK
_rc5_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)53 static int _rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
54 #else
55 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
56 #endif
57 {
58 ulong32 L[64], *S, A, B, i, j, v, s, t, l;
59
60 LTC_ARGCHK(skey != NULL);
61 LTC_ARGCHK(key != NULL);
62
63 /* test parameters */
64 if (num_rounds == 0) {
65 num_rounds = rc5_desc.default_rounds;
66 }
67
68 if (num_rounds < 12 || num_rounds > 24) {
69 return CRYPT_INVALID_ROUNDS;
70 }
71
72 /* key must be between 64 and 1024 bits */
73 if (keylen < 8 || keylen > 128) {
74 return CRYPT_INVALID_KEYSIZE;
75 }
76
77 skey->rc5.rounds = num_rounds;
78 S = skey->rc5.K;
79
80 /* copy the key into the L array */
81 for (A = i = j = 0; i < (ulong32)keylen; ) {
82 A = (A << 8) | ((ulong32)(key[i++] & 255));
83 if ((i & 3) == 0) {
84 L[j++] = BSWAP(A);
85 A = 0;
86 }
87 }
88
89 if ((keylen & 3) != 0) {
90 A <<= (ulong32)((8 * (4 - (keylen&3))));
91 L[j++] = BSWAP(A);
92 }
93
94 /* setup the S array */
95 t = (ulong32)(2 * (num_rounds + 1));
96 XMEMCPY(S, stab, t * sizeof(*S));
97
98 /* mix buffer */
99 s = 3 * MAX(t, j);
100 l = j;
101 for (A = B = i = j = v = 0; v < s; v++) {
102 A = S[i] = ROLc(S[i] + A + B, 3);
103 B = L[j] = ROL(L[j] + A + B, (A+B));
104 if (++i == t) { i = 0; }
105 if (++j == l) { j = 0; }
106 }
107 return CRYPT_OK;
108 }
109
110 #ifdef LTC_CLEAN_STACK
rc5_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)111 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
112 {
113 int x;
114 x = _rc5_setup(key, keylen, num_rounds, skey);
115 burn_stack(sizeof(ulong32) * 122 + sizeof(int));
116 return x;
117 }
118 #endif
119
120 /**
121 Encrypts a block of text with LTC_RC5
122 @param pt The input plaintext (8 bytes)
123 @param ct The output ciphertext (8 bytes)
124 @param skey The key as scheduled
125 @return CRYPT_OK if successful
126 */
127 #ifdef LTC_CLEAN_STACK
_rc5_ecb_encrypt(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)128 static int _rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
129 #else
130 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
131 #endif
132 {
133 ulong32 A, B;
134 const ulong32 *K;
135 int r;
136 LTC_ARGCHK(skey != NULL);
137 LTC_ARGCHK(pt != NULL);
138 LTC_ARGCHK(ct != NULL);
139
140 LOAD32L(A, &pt[0]);
141 LOAD32L(B, &pt[4]);
142 A += skey->rc5.K[0];
143 B += skey->rc5.K[1];
144 K = skey->rc5.K + 2;
145
146 if ((skey->rc5.rounds & 1) == 0) {
147 for (r = 0; r < skey->rc5.rounds; r += 2) {
148 A = ROL(A ^ B, B) + K[0];
149 B = ROL(B ^ A, A) + K[1];
150 A = ROL(A ^ B, B) + K[2];
151 B = ROL(B ^ A, A) + K[3];
152 K += 4;
153 }
154 } else {
155 for (r = 0; r < skey->rc5.rounds; r++) {
156 A = ROL(A ^ B, B) + K[0];
157 B = ROL(B ^ A, A) + K[1];
158 K += 2;
159 }
160 }
161 STORE32L(A, &ct[0]);
162 STORE32L(B, &ct[4]);
163
164 return CRYPT_OK;
165 }
166
167 #ifdef LTC_CLEAN_STACK
rc5_ecb_encrypt(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)168 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
169 {
170 int err = _rc5_ecb_encrypt(pt, ct, skey);
171 burn_stack(sizeof(ulong32) * 2 + sizeof(int));
172 return err;
173 }
174 #endif
175
176 /**
177 Decrypts a block of text with LTC_RC5
178 @param ct The input ciphertext (8 bytes)
179 @param pt The output plaintext (8 bytes)
180 @param skey The key as scheduled
181 @return CRYPT_OK if successful
182 */
183 #ifdef LTC_CLEAN_STACK
_rc5_ecb_decrypt(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)184 static int _rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
185 #else
186 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
187 #endif
188 {
189 ulong32 A, B;
190 const ulong32 *K;
191 int r;
192 LTC_ARGCHK(skey != NULL);
193 LTC_ARGCHK(pt != NULL);
194 LTC_ARGCHK(ct != NULL);
195
196 LOAD32L(A, &ct[0]);
197 LOAD32L(B, &ct[4]);
198 K = skey->rc5.K + (skey->rc5.rounds << 1);
199
200 if ((skey->rc5.rounds & 1) == 0) {
201 K -= 2;
202 for (r = skey->rc5.rounds - 1; r >= 0; r -= 2) {
203 B = ROR(B - K[3], A) ^ A;
204 A = ROR(A - K[2], B) ^ B;
205 B = ROR(B - K[1], A) ^ A;
206 A = ROR(A - K[0], B) ^ B;
207 K -= 4;
208 }
209 } else {
210 for (r = skey->rc5.rounds - 1; r >= 0; r--) {
211 B = ROR(B - K[1], A) ^ A;
212 A = ROR(A - K[0], B) ^ B;
213 K -= 2;
214 }
215 }
216 A -= skey->rc5.K[0];
217 B -= skey->rc5.K[1];
218 STORE32L(A, &pt[0]);
219 STORE32L(B, &pt[4]);
220
221 return CRYPT_OK;
222 }
223
224 #ifdef LTC_CLEAN_STACK
rc5_ecb_decrypt(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)225 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
226 {
227 int err = _rc5_ecb_decrypt(ct, pt, skey);
228 burn_stack(sizeof(ulong32) * 2 + sizeof(int));
229 return err;
230 }
231 #endif
232
233 /**
234 Performs a self-test of the LTC_RC5 block cipher
235 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
236 */
rc5_test(void)237 int rc5_test(void)
238 {
239 #ifndef LTC_TEST
240 return CRYPT_NOP;
241 #else
242 static const struct {
243 unsigned char key[16], pt[8], ct[8];
244 } tests[] = {
245 {
246 { 0x91, 0x5f, 0x46, 0x19, 0xbe, 0x41, 0xb2, 0x51,
247 0x63, 0x55, 0xa5, 0x01, 0x10, 0xa9, 0xce, 0x91 },
248 { 0x21, 0xa5, 0xdb, 0xee, 0x15, 0x4b, 0x8f, 0x6d },
249 { 0xf7, 0xc0, 0x13, 0xac, 0x5b, 0x2b, 0x89, 0x52 }
250 },
251 {
252 { 0x78, 0x33, 0x48, 0xe7, 0x5a, 0xeb, 0x0f, 0x2f,
253 0xd7, 0xb1, 0x69, 0xbb, 0x8d, 0xc1, 0x67, 0x87 },
254 { 0xF7, 0xC0, 0x13, 0xAC, 0x5B, 0x2B, 0x89, 0x52 },
255 { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 }
256 },
257 {
258 { 0xDC, 0x49, 0xdb, 0x13, 0x75, 0xa5, 0x58, 0x4f,
259 0x64, 0x85, 0xb4, 0x13, 0xb5, 0xf1, 0x2b, 0xaf },
260 { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 },
261 { 0x65, 0xc1, 0x78, 0xb2, 0x84, 0xd1, 0x97, 0xcc }
262 }
263 };
264 unsigned char tmp[2][8];
265 int x, y, err;
266 symmetric_key key;
267
268 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
269 /* setup key */
270 if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) {
271 return err;
272 }
273
274 /* encrypt and decrypt */
275 rc5_ecb_encrypt(tests[x].pt, tmp[0], &key);
276 rc5_ecb_decrypt(tmp[0], tmp[1], &key);
277
278 /* compare */
279 if (compare_testvector(tmp[0], 8, tests[x].ct, 8, "RC5 Encrypt", x) != 0 ||
280 compare_testvector(tmp[1], 8, tests[x].pt, 8, "RC5 Decrypt", x) != 0) {
281 return CRYPT_FAIL_TESTVECTOR;
282 }
283
284 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
285 for (y = 0; y < 8; y++) tmp[0][y] = 0;
286 for (y = 0; y < 1000; y++) rc5_ecb_encrypt(tmp[0], tmp[0], &key);
287 for (y = 0; y < 1000; y++) rc5_ecb_decrypt(tmp[0], tmp[0], &key);
288 for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
289 }
290 return CRYPT_OK;
291 #endif
292 }
293
294 /** Terminate the context
295 @param skey The scheduled key
296 */
rc5_done(symmetric_key * skey)297 void rc5_done(symmetric_key *skey)
298 {
299 LTC_UNUSED_PARAM(skey);
300 }
301
302 /**
303 Gets suitable key size
304 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
305 @return CRYPT_OK if the input key size is acceptable.
306 */
rc5_keysize(int * keysize)307 int rc5_keysize(int *keysize)
308 {
309 LTC_ARGCHK(keysize != NULL);
310 if (*keysize < 8) {
311 return CRYPT_INVALID_KEYSIZE;
312 }
313 if (*keysize > 128) {
314 *keysize = 128;
315 }
316 return CRYPT_OK;
317 }
318
319 #endif
320
321
322
323
324 /* ref: $Format:%D$ */
325 /* git commit: $Format:%H$ */
326 /* commit time: $Format:%ai$ */
327