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Diffstat (limited to 'libtomcrypt/src/ciphers/rc5.c')
| -rw-r--r-- | libtomcrypt/src/ciphers/rc5.c | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/libtomcrypt/src/ciphers/rc5.c b/libtomcrypt/src/ciphers/rc5.c new file mode 100644 index 0000000..2d5fdb8 --- /dev/null +++ b/libtomcrypt/src/ciphers/rc5.c @@ -0,0 +1,322 @@ +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com + */ + +/** + @file rc5.c + RC5 code by Tom St Denis +*/ + +#include "tomcrypt.h" + +#ifdef RC5 + +const struct ltc_cipher_descriptor rc5_desc = +{ + "rc5", + 2, + 8, 128, 8, 12, + &rc5_setup, + &rc5_ecb_encrypt, + &rc5_ecb_decrypt, + &rc5_test, + &rc5_done, + &rc5_keysize, + NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL +}; + +static const ulong32 stab[50] = { +0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL, +0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL, +0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL, +0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL, +0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL, +0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL, 0xe96a3d2fUL, 0x87a1b6e8UL, 0x25d930a1UL, 0xc410aa5aUL, +0x62482413UL, 0x007f9dccUL +}; + + /** + Initialize the RC5 block cipher + @param key The symmetric key you wish to pass + @param keylen The key length in bytes + @param num_rounds The number of rounds desired (0 for default) + @param skey The key in as scheduled by this function. + @return CRYPT_OK if successful + */ +#ifdef LTC_CLEAN_STACK +static int _rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) +#else +int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) +#endif +{ + ulong32 L[64], *S, A, B, i, j, v, s, t, l; + + LTC_ARGCHK(skey != NULL); + LTC_ARGCHK(key != NULL); + + /* test parameters */ + if (num_rounds == 0) { + num_rounds = rc5_desc.default_rounds; + } + + if (num_rounds < 12 || num_rounds > 24) { + return CRYPT_INVALID_ROUNDS; + } + + /* key must be between 64 and 1024 bits */ + if (keylen < 8 || keylen > 128) { + return CRYPT_INVALID_KEYSIZE; + } + + skey->rc5.rounds = num_rounds; + S = skey->rc5.K; + + /* copy the key into the L array */ + for (A = i = j = 0; i < (ulong32)keylen; ) { + A = (A << 8) | ((ulong32)(key[i++] & 255)); + if ((i & 3) == 0) { + L[j++] = BSWAP(A); + A = 0; + } + } + + if ((keylen & 3) != 0) { + A <<= (ulong32)((8 * (4 - (keylen&3)))); + L[j++] = BSWAP(A); + } + + /* setup the S array */ + t = (ulong32)(2 * (num_rounds + 1)); + XMEMCPY(S, stab, t * sizeof(*S)); + + /* mix buffer */ + s = 3 * MAX(t, j); + l = j; + for (A = B = i = j = v = 0; v < s; v++) { + A = S[i] = ROLc(S[i] + A + B, 3); + B = L[j] = ROL(L[j] + A + B, (A+B)); + if (++i == t) { i = 0; } + if (++j == l) { j = 0; } + } + return CRYPT_OK; +} + +#ifdef LTC_CLEAN_STACK +int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) +{ + int x; + x = _rc5_setup(key, keylen, num_rounds, skey); + burn_stack(sizeof(ulong32) * 122 + sizeof(int)); + return x; +} +#endif + +/** + Encrypts a block of text with RC5 + @param pt The input plaintext (8 bytes) + @param ct The output ciphertext (8 bytes) + @param skey The key as scheduled + @return CRYPT_OK if successful +*/ +#ifdef LTC_CLEAN_STACK +static int _rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) +#else +int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) +#endif +{ + ulong32 A, B, *K; + int r; + LTC_ARGCHK(skey != NULL); + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + + LOAD32L(A, &pt[0]); + LOAD32L(B, &pt[4]); + A += skey->rc5.K[0]; + B += skey->rc5.K[1]; + K = skey->rc5.K + 2; + + if ((skey->rc5.rounds & 1) == 0) { + for (r = 0; r < skey->rc5.rounds; r += 2) { + A = ROL(A ^ B, B) + K[0]; + B = ROL(B ^ A, A) + K[1]; + A = ROL(A ^ B, B) + K[2]; + B = ROL(B ^ A, A) + K[3]; + K += 4; + } + } else { + for (r = 0; r < skey->rc5.rounds; r++) { + A = ROL(A ^ B, B) + K[0]; + B = ROL(B ^ A, A) + K[1]; + K += 2; + } + } + STORE32L(A, &ct[0]); + STORE32L(B, &ct[4]); + + return CRYPT_OK; +} + +#ifdef LTC_CLEAN_STACK +int rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) +{ + int err = _rc5_ecb_encrypt(pt, ct, skey); + burn_stack(sizeof(ulong32) * 2 + sizeof(int)); + return err; +} +#endif + +/** + Decrypts a block of text with RC5 + @param ct The input ciphertext (8 bytes) + @param pt The output plaintext (8 bytes) + @param skey The key as scheduled + @return CRYPT_OK if successful +*/ +#ifdef LTC_CLEAN_STACK +static int _rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) +#else +int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) +#endif +{ + ulong32 A, B, *K; + int r; + LTC_ARGCHK(skey != NULL); + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + + LOAD32L(A, &ct[0]); + LOAD32L(B, &ct[4]); + K = skey->rc5.K + (skey->rc5.rounds << 1); + + if ((skey->rc5.rounds & 1) == 0) { + K -= 2; + for (r = skey->rc5.rounds - 1; r >= 0; r -= 2) { + B = ROR(B - K[3], A) ^ A; + A = ROR(A - K[2], B) ^ B; + B = ROR(B - K[1], A) ^ A; + A = ROR(A - K[0], B) ^ B; + K -= 4; + } + } else { + for (r = skey->rc5.rounds - 1; r >= 0; r--) { + B = ROR(B - K[1], A) ^ A; + A = ROR(A - K[0], B) ^ B; + K -= 2; + } + } + A -= skey->rc5.K[0]; + B -= skey->rc5.K[1]; + STORE32L(A, &pt[0]); + STORE32L(B, &pt[4]); + + return CRYPT_OK; +} + +#ifdef LTC_CLEAN_STACK +int rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) +{ + int err = _rc5_ecb_decrypt(ct, pt, skey); + burn_stack(sizeof(ulong32) * 2 + sizeof(int)); + return err; +} +#endif + +/** + Performs a self-test of the RC5 block cipher + @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled +*/ +int rc5_test(void) +{ + #ifndef LTC_TEST + return CRYPT_NOP; + #else + static const struct { + unsigned char key[16], pt[8], ct[8]; + } tests[] = { + { + { 0x91, 0x5f, 0x46, 0x19, 0xbe, 0x41, 0xb2, 0x51, + 0x63, 0x55, 0xa5, 0x01, 0x10, 0xa9, 0xce, 0x91 }, + { 0x21, 0xa5, 0xdb, 0xee, 0x15, 0x4b, 0x8f, 0x6d }, + { 0xf7, 0xc0, 0x13, 0xac, 0x5b, 0x2b, 0x89, 0x52 } + }, + { + { 0x78, 0x33, 0x48, 0xe7, 0x5a, 0xeb, 0x0f, 0x2f, + 0xd7, 0xb1, 0x69, 0xbb, 0x8d, 0xc1, 0x67, 0x87 }, + { 0xF7, 0xC0, 0x13, 0xAC, 0x5B, 0x2B, 0x89, 0x52 }, + { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 } + }, + { + { 0xDC, 0x49, 0xdb, 0x13, 0x75, 0xa5, 0x58, 0x4f, + 0x64, 0x85, 0xb4, 0x13, 0xb5, 0xf1, 0x2b, 0xaf }, + { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 }, + { 0x65, 0xc1, 0x78, 0xb2, 0x84, 0xd1, 0x97, 0xcc } + } + }; + unsigned char tmp[2][8]; + int x, y, err; + symmetric_key key; + + for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) { + /* setup key */ + if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) { + return err; + } + + /* encrypt and decrypt */ + rc5_ecb_encrypt(tests[x].pt, tmp[0], &key); + rc5_ecb_decrypt(tmp[0], tmp[1], &key); + + /* compare */ + if (XMEMCMP(tmp[0], tests[x].ct, 8) != 0 || XMEMCMP(tmp[1], tests[x].pt, 8) != 0) { + return CRYPT_FAIL_TESTVECTOR; + } + + /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */ + for (y = 0; y < 8; y++) tmp[0][y] = 0; + for (y = 0; y < 1000; y++) rc5_ecb_encrypt(tmp[0], tmp[0], &key); + for (y = 0; y < 1000; y++) rc5_ecb_decrypt(tmp[0], tmp[0], &key); + for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; + } + return CRYPT_OK; + #endif +} + +/** Terminate the context + @param skey The scheduled key +*/ +void rc5_done(symmetric_key *skey) +{ +} + +/** + Gets suitable key size + @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable. + @return CRYPT_OK if the input key size is acceptable. +*/ +int rc5_keysize(int *keysize) +{ + LTC_ARGCHK(keysize != NULL); + if (*keysize < 8) { + return CRYPT_INVALID_KEYSIZE; + } else if (*keysize > 128) { + *keysize = 128; + } + return CRYPT_OK; +} + +#endif + + + + +/* $Source: /cvs/libtom/libtomcrypt/src/ciphers/rc5.c,v $ */ +/* $Revision: 1.12 $ */ +/* $Date: 2006/11/08 23:01:06 $ */ |