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
10 /**
11 @file rc5.c
12 LTC_RC5 code by Tom St Denis
13 */
14
15 #include "tomcrypt.h"
16
17 #ifdef LTC_RC5
18
19 const struct ltc_cipher_descriptor rc5_desc =
20 {
21 "rc5",
22 2,
23 8, 128, 8, 12,
24 &rc5_setup,
25 &rc5_ecb_encrypt,
26 &rc5_ecb_decrypt,
27 &rc5_test,
28 &rc5_done,
29 &rc5_keysize,
30 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
31 };
32
33 static const ulong32 stab[50] = {
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, 0xe96a3d2fUL, 0x87a1b6e8UL, 0x25d930a1UL, 0xc410aa5aUL,
40 0x62482413UL, 0x007f9dccUL
41 };
42
43 /**
44 Initialize the LTC_RC5 block cipher
45 @param key The symmetric key you wish to pass
46 @param keylen The key length in bytes
47 @param num_rounds The number of rounds desired (0 for default)
48 @param skey The key in as scheduled by this function.
49 @return CRYPT_OK if successful
50 */
51 #ifdef LTC_CLEAN_STACK
_rc5_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)52 static int _rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
53 #else
54 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
55 #endif
56 {
57 ulong32 L[64], *S, A, B, i, j, v, s, t, l;
58
59 LTC_ARGCHK(skey != NULL);
60 LTC_ARGCHK(key != NULL);
61
62 /* test parameters */
63 if (num_rounds == 0) {
64 num_rounds = rc5_desc.default_rounds;
65 }
66
67 if (num_rounds < 12 || num_rounds > 24) {
68 return CRYPT_INVALID_ROUNDS;
69 }
70
71 /* key must be between 64 and 1024 bits */
72 if (keylen < 8 || keylen > 128) {
73 return CRYPT_INVALID_KEYSIZE;
74 }
75
76 skey->rc5.rounds = num_rounds;
77 S = skey->rc5.K;
78
79 /* copy the key into the L array */
80 for (A = i = j = 0; i < (ulong32)keylen; ) {
81 A = (A << 8) | ((ulong32)(key[i++] & 255));
82 if ((i & 3) == 0) {
83 L[j++] = BSWAP(A);
84 A = 0;
85 }
86 }
87
88 if ((keylen & 3) != 0) {
89 A <<= (ulong32)((8 * (4 - (keylen&3))));
90 L[j++] = BSWAP(A);
91 }
92
93 /* setup the S array */
94 t = (ulong32)(2 * (num_rounds + 1));
95 XMEMCPY(S, stab, t * sizeof(*S));
96
97 /* mix buffer */
98 s = 3 * MAX(t, j);
99 l = j;
100 for (A = B = i = j = v = 0; v < s; v++) {
101 A = S[i] = ROLc(S[i] + A + B, 3);
102 B = L[j] = ROL(L[j] + A + B, (A+B));
103 if (++i == t) { i = 0; }
104 if (++j == l) { j = 0; }
105 }
106 return CRYPT_OK;
107 }
108
109 #ifdef LTC_CLEAN_STACK
rc5_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)110 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
111 {
112 int x;
113 x = _rc5_setup(key, keylen, num_rounds, skey);
114 burn_stack(sizeof(ulong32) * 122 + sizeof(int));
115 return x;
116 }
117 #endif
118
119 /**
120 Encrypts a block of text with LTC_RC5
121 @param pt The input plaintext (8 bytes)
122 @param ct The output ciphertext (8 bytes)
123 @param skey The key as scheduled
124 @return CRYPT_OK if successful
125 */
126 #ifdef LTC_CLEAN_STACK
_rc5_ecb_encrypt(const unsigned char * pt,unsigned char * ct,symmetric_key * skey)127 static int _rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
128 #else
129 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
130 #endif
131 {
132 ulong32 A, B, *K;
133 int r;
134 LTC_ARGCHK(skey != NULL);
135 LTC_ARGCHK(pt != NULL);
136 LTC_ARGCHK(ct != NULL);
137
138 LOAD32L(A, &pt[0]);
139 LOAD32L(B, &pt[4]);
140 A += skey->rc5.K[0];
141 B += skey->rc5.K[1];
142 K = skey->rc5.K + 2;
143
144 if ((skey->rc5.rounds & 1) == 0) {
145 for (r = 0; r < skey->rc5.rounds; r += 2) {
146 A = ROL(A ^ B, B) + K[0];
147 B = ROL(B ^ A, A) + K[1];
148 A = ROL(A ^ B, B) + K[2];
149 B = ROL(B ^ A, A) + K[3];
150 K += 4;
151 }
152 } else {
153 for (r = 0; r < skey->rc5.rounds; r++) {
154 A = ROL(A ^ B, B) + K[0];
155 B = ROL(B ^ A, A) + K[1];
156 K += 2;
157 }
158 }
159 STORE32L(A, &ct[0]);
160 STORE32L(B, &ct[4]);
161
162 return CRYPT_OK;
163 }
164
165 #ifdef LTC_CLEAN_STACK
rc5_ecb_encrypt(const unsigned char * pt,unsigned char * ct,symmetric_key * skey)166 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
167 {
168 int err = _rc5_ecb_encrypt(pt, ct, skey);
169 burn_stack(sizeof(ulong32) * 2 + sizeof(int));
170 return err;
171 }
172 #endif
173
174 /**
175 Decrypts a block of text with LTC_RC5
176 @param ct The input ciphertext (8 bytes)
177 @param pt The output plaintext (8 bytes)
178 @param skey The key as scheduled
179 @return CRYPT_OK if successful
180 */
181 #ifdef LTC_CLEAN_STACK
_rc5_ecb_decrypt(const unsigned char * ct,unsigned char * pt,symmetric_key * skey)182 static int _rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
183 #else
184 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
185 #endif
186 {
187 ulong32 A, B, *K;
188 int r;
189 LTC_ARGCHK(skey != NULL);
190 LTC_ARGCHK(pt != NULL);
191 LTC_ARGCHK(ct != NULL);
192
193 LOAD32L(A, &ct[0]);
194 LOAD32L(B, &ct[4]);
195 K = skey->rc5.K + (skey->rc5.rounds << 1);
196
197 if ((skey->rc5.rounds & 1) == 0) {
198 K -= 2;
199 for (r = skey->rc5.rounds - 1; r >= 0; r -= 2) {
200 B = ROR(B - K[3], A) ^ A;
201 A = ROR(A - K[2], B) ^ B;
202 B = ROR(B - K[1], A) ^ A;
203 A = ROR(A - K[0], B) ^ B;
204 K -= 4;
205 }
206 } else {
207 for (r = skey->rc5.rounds - 1; r >= 0; r--) {
208 B = ROR(B - K[1], A) ^ A;
209 A = ROR(A - K[0], B) ^ B;
210 K -= 2;
211 }
212 }
213 A -= skey->rc5.K[0];
214 B -= skey->rc5.K[1];
215 STORE32L(A, &pt[0]);
216 STORE32L(B, &pt[4]);
217
218 return CRYPT_OK;
219 }
220
221 #ifdef LTC_CLEAN_STACK
rc5_ecb_decrypt(const unsigned char * ct,unsigned char * pt,symmetric_key * skey)222 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
223 {
224 int err = _rc5_ecb_decrypt(ct, pt, skey);
225 burn_stack(sizeof(ulong32) * 2 + sizeof(int));
226 return err;
227 }
228 #endif
229
230 /**
231 Performs a self-test of the LTC_RC5 block cipher
232 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
233 */
rc5_test(void)234 int rc5_test(void)
235 {
236 #ifndef LTC_TEST
237 return CRYPT_NOP;
238 #else
239 static const struct {
240 unsigned char key[16], pt[8], ct[8];
241 } tests[] = {
242 {
243 { 0x91, 0x5f, 0x46, 0x19, 0xbe, 0x41, 0xb2, 0x51,
244 0x63, 0x55, 0xa5, 0x01, 0x10, 0xa9, 0xce, 0x91 },
245 { 0x21, 0xa5, 0xdb, 0xee, 0x15, 0x4b, 0x8f, 0x6d },
246 { 0xf7, 0xc0, 0x13, 0xac, 0x5b, 0x2b, 0x89, 0x52 }
247 },
248 {
249 { 0x78, 0x33, 0x48, 0xe7, 0x5a, 0xeb, 0x0f, 0x2f,
250 0xd7, 0xb1, 0x69, 0xbb, 0x8d, 0xc1, 0x67, 0x87 },
251 { 0xF7, 0xC0, 0x13, 0xAC, 0x5B, 0x2B, 0x89, 0x52 },
252 { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 }
253 },
254 {
255 { 0xDC, 0x49, 0xdb, 0x13, 0x75, 0xa5, 0x58, 0x4f,
256 0x64, 0x85, 0xb4, 0x13, 0xb5, 0xf1, 0x2b, 0xaf },
257 { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 },
258 { 0x65, 0xc1, 0x78, 0xb2, 0x84, 0xd1, 0x97, 0xcc }
259 }
260 };
261 unsigned char tmp[2][8];
262 int x, y, err;
263 symmetric_key key;
264
265 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
266 /* setup key */
267 if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) {
268 return err;
269 }
270
271 /* encrypt and decrypt */
272 rc5_ecb_encrypt(tests[x].pt, tmp[0], &key);
273 rc5_ecb_decrypt(tmp[0], tmp[1], &key);
274
275 /* compare */
276 if (compare_testvector(tmp[0], 8, tests[x].ct, 8, "RC5 Encrypt", x) != 0 ||
277 compare_testvector(tmp[1], 8, tests[x].pt, 8, "RC5 Decrypt", x) != 0) {
278 return CRYPT_FAIL_TESTVECTOR;
279 }
280
281 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
282 for (y = 0; y < 8; y++) tmp[0][y] = 0;
283 for (y = 0; y < 1000; y++) rc5_ecb_encrypt(tmp[0], tmp[0], &key);
284 for (y = 0; y < 1000; y++) rc5_ecb_decrypt(tmp[0], tmp[0], &key);
285 for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
286 }
287 return CRYPT_OK;
288 #endif
289 }
290
291 /** Terminate the context
292 @param skey The scheduled key
293 */
rc5_done(symmetric_key * skey)294 void rc5_done(symmetric_key *skey)
295 {
296 LTC_UNUSED_PARAM(skey);
297 }
298
299 /**
300 Gets suitable key size
301 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
302 @return CRYPT_OK if the input key size is acceptable.
303 */
rc5_keysize(int * keysize)304 int rc5_keysize(int *keysize)
305 {
306 LTC_ARGCHK(keysize != NULL);
307 if (*keysize < 8) {
308 return CRYPT_INVALID_KEYSIZE;
309 } else if (*keysize > 128) {
310 *keysize = 128;
311 }
312 return CRYPT_OK;
313 }
314
315 #endif
316
317
318
319
320 /* ref: $Format:%D$ */
321 /* git commit: $Format:%H$ */
322 /* commit time: $Format:%ai$ */
323