Mercurial > dropbear
view libtomcrypt/src/ciphers/rc5.c @ 493:6cd2152aae0b idle-timeout
Idle-timeout patch from Farrell Aultman, need to figure whether to only
account DATA packets and whether server->client data makes sense too.
author | Matt Johnston <matt@ucc.asn.au> |
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date | Mon, 22 Sep 2008 15:28:52 +0000 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
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/* 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, [email protected], 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 $ */