1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
6 * The library is free for all purposes without any express
12 LTC_RC5 code by Tom St Denis
19 const struct ltc_cipher_descriptor rc5_desc =
30 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
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
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
51 #ifdef LTC_CLEAN_STACK
52 static int _rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
54 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
57 ulong32 L[64], *S, A, B, i, j, v, s, t, l;
59 LTC_ARGCHK(skey != NULL);
60 LTC_ARGCHK(key != NULL);
63 if (num_rounds == 0) {
64 num_rounds = rc5_desc.default_rounds;
67 if (num_rounds < 12 || num_rounds > 24) {
68 return CRYPT_INVALID_ROUNDS;
71 /* key must be between 64 and 1024 bits */
72 if (keylen < 8 || keylen > 128) {
73 return CRYPT_INVALID_KEYSIZE;
76 skey->rc5.rounds = num_rounds;
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));
88 if ((keylen & 3) != 0) {
89 A <<= (ulong32)((8 * (4 - (keylen&3))));
93 /* setup the S array */
94 t = (ulong32)(2 * (num_rounds + 1));
95 XMEMCPY(S, stab, t * sizeof(*S));
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; }
109 #ifdef LTC_CLEAN_STACK
110 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
113 x = _rc5_setup(key, keylen, num_rounds, skey);
114 burn_stack(sizeof(ulong32) * 122 + sizeof(int));
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
126 #ifdef LTC_CLEAN_STACK
127 static int _rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
129 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
134 LTC_ARGCHK(skey != NULL);
135 LTC_ARGCHK(pt != NULL);
136 LTC_ARGCHK(ct != NULL);
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];
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];
165 #ifdef LTC_CLEAN_STACK
166 int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
168 int err = _rc5_ecb_encrypt(pt, ct, skey);
169 burn_stack(sizeof(ulong32) * 2 + sizeof(int));
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
181 #ifdef LTC_CLEAN_STACK
182 static int _rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
184 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
189 LTC_ARGCHK(skey != NULL);
190 LTC_ARGCHK(pt != NULL);
191 LTC_ARGCHK(ct != NULL);
195 K = skey->rc5.K + (skey->rc5.rounds << 1);
197 if ((skey->rc5.rounds & 1) == 0) {
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;
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;
221 #ifdef LTC_CLEAN_STACK
222 int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
224 int err = _rc5_ecb_decrypt(ct, pt, skey);
225 burn_stack(sizeof(ulong32) * 2 + sizeof(int));
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
239 static const struct {
240 unsigned char key[16], pt[8], ct[8];
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 }
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 }
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 }
261 unsigned char tmp[2][8];
265 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
267 if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) {
271 /* encrypt and decrypt */
272 rc5_ecb_encrypt(tests[x].pt, tmp[0], &key);
273 rc5_ecb_decrypt(tmp[0], tmp[1], &key);
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;
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;
291 /** Terminate the context
292 @param skey The scheduled key
294 void rc5_done(symmetric_key *skey)
296 LTC_UNUSED_PARAM(skey);
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.
304 int rc5_keysize(int *keysize)
306 LTC_ARGCHK(keysize != NULL);
308 return CRYPT_INVALID_KEYSIZE;
309 } else if (*keysize > 128) {
320 /* ref: $Format:%D$ */
321 /* git commit: $Format:%H$ */
322 /* commit time: $Format:%ai$ */