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Diffstat (limited to 'src/ciphers/rc6.c')
| -rw-r--r-- | src/ciphers/rc6.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/src/ciphers/rc6.c b/src/ciphers/rc6.c new file mode 100644 index 0000000..ae6f114 --- /dev/null +++ b/src/ciphers/rc6.c @@ -0,0 +1,343 @@ +/* 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.org + */ + +/** + @file rc6.c + RC6 code by Tom St Denis +*/ +#include "tomcrypt.h" + +#ifdef RC6 + +const struct ltc_cipher_descriptor rc6_desc = +{ + "rc6", + 3, + 8, 128, 16, 20, + &rc6_setup, + &rc6_ecb_encrypt, + &rc6_ecb_decrypt, + &rc6_test, + &rc6_done, + &rc6_keysize, + NULL, NULL, NULL, NULL, NULL, NULL, NULL +}; + +static const ulong32 stab[44] = { +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 }; + + /** + Initialize the RC6 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 _rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) +#else +int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) +#endif +{ + ulong32 L[64], S[50], A, B, i, j, v, s, l; + + LTC_ARGCHK(key != NULL); + LTC_ARGCHK(skey != NULL); + + /* test parameters */ + if (num_rounds != 0 && num_rounds != 20) { + return CRYPT_INVALID_ROUNDS; + } + + /* key must be between 64 and 1024 bits */ + if (keylen < 8 || keylen > 128) { + return CRYPT_INVALID_KEYSIZE; + } + + /* 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)) { + L[j++] = BSWAP(A); + A = 0; + } + } + + /* handle odd sized keys */ + if (keylen & 3) { + A <<= (8 * (4 - (keylen&3))); + L[j++] = BSWAP(A); + } + + /* setup the S array */ + XMEMCPY(S, stab, 44 * sizeof(stab[0])); + + /* mix buffer */ + s = 3 * MAX(44, 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 == 44) { i = 0; } + if (++j == l) { j = 0; } + } + + /* copy to key */ + for (i = 0; i < 44; i++) { + skey->rc6.K[i] = S[i]; + } + return CRYPT_OK; +} + +#ifdef LTC_CLEAN_STACK +int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) +{ + int x; + x = _rc6_setup(key, keylen, num_rounds, skey); + burn_stack(sizeof(ulong32) * 122); + return x; +} +#endif + +/** + Encrypts a block of text with RC6 + @param pt The input plaintext (16 bytes) + @param ct The output ciphertext (16 bytes) + @param skey The key as scheduled +*/ +#ifdef LTC_CLEAN_STACK +static void _rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) +#else +void rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) +#endif +{ + ulong32 a,b,c,d,t,u, *K; + int r; + + LTC_ARGCHK(skey != NULL); + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + LOAD32L(a,&pt[0]);LOAD32L(b,&pt[4]);LOAD32L(c,&pt[8]);LOAD32L(d,&pt[12]); + + b += skey->rc6.K[0]; + d += skey->rc6.K[1]; + +#define RND(a,b,c,d) \ + t = (b * (b + b + 1)); t = ROLc(t, 5); \ + u = (d * (d + d + 1)); u = ROLc(u, 5); \ + a = ROL(a^t,u) + K[0]; \ + c = ROL(c^u,t) + K[1]; K += 2; + + K = skey->rc6.K + 2; + for (r = 0; r < 20; r += 4) { + RND(a,b,c,d); + RND(b,c,d,a); + RND(c,d,a,b); + RND(d,a,b,c); + } + +#undef RND + + a += skey->rc6.K[42]; + c += skey->rc6.K[43]; + STORE32L(a,&ct[0]);STORE32L(b,&ct[4]);STORE32L(c,&ct[8]);STORE32L(d,&ct[12]); +} + +#ifdef LTC_CLEAN_STACK +void rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) +{ + _rc6_ecb_encrypt(pt, ct, skey); + burn_stack(sizeof(ulong32) * 6 + sizeof(int)); +} +#endif + +/** + Decrypts a block of text with RC6 + @param ct The input ciphertext (16 bytes) + @param pt The output plaintext (16 bytes) + @param skey The key as scheduled +*/ +#ifdef LTC_CLEAN_STACK +static void _rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) +#else +void rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) +#endif +{ + ulong32 a,b,c,d,t,u, *K; + int r; + + LTC_ARGCHK(skey != NULL); + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + + LOAD32L(a,&ct[0]);LOAD32L(b,&ct[4]);LOAD32L(c,&ct[8]);LOAD32L(d,&ct[12]); + a -= skey->rc6.K[42]; + c -= skey->rc6.K[43]; + +#define RND(a,b,c,d) \ + t = (b * (b + b + 1)); t = ROLc(t, 5); \ + u = (d * (d + d + 1)); u = ROLc(u, 5); \ + c = ROR(c - K[1], t) ^ u; \ + a = ROR(a - K[0], u) ^ t; K -= 2; + + K = skey->rc6.K + 40; + + for (r = 0; r < 20; r += 4) { + RND(d,a,b,c); + RND(c,d,a,b); + RND(b,c,d,a); + RND(a,b,c,d); + } + +#undef RND + + b -= skey->rc6.K[0]; + d -= skey->rc6.K[1]; + STORE32L(a,&pt[0]);STORE32L(b,&pt[4]);STORE32L(c,&pt[8]);STORE32L(d,&pt[12]); +} + +#ifdef LTC_CLEAN_STACK +void rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) +{ + _rc6_ecb_decrypt(ct, pt, skey); + burn_stack(sizeof(ulong32) * 6 + sizeof(int)); +} +#endif + +/** + Performs a self-test of the RC6 block cipher + @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled +*/ +int rc6_test(void) +{ + #ifndef LTC_TEST + return CRYPT_NOP; + #else + static const struct { + int keylen; + unsigned char key[32], pt[16], ct[16]; + } tests[] = { + { + 16, + { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, + 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, + { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, + 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, + { 0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23, + 0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4, 0x3f, 0x18 } + }, + { + 24, + { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, + 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, + 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, + { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, + 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, + { 0x68, 0x83, 0x29, 0xd0, 0x19, 0xe5, 0x05, 0x04, + 0x1e, 0x52, 0xe9, 0x2a, 0xf9, 0x52, 0x91, 0xd4 } + }, + { + 32, + { 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, + 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78, + 0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0, + 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe }, + { 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79, + 0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 }, + { 0xc8, 0x24, 0x18, 0x16, 0xf0, 0xd7, 0xe4, 0x89, + 0x20, 0xad, 0x16, 0xa1, 0x67, 0x4e, 0x5d, 0x48 } + } + }; + unsigned char tmp[2][16]; + int x, y, err; + symmetric_key key; + + for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) { + /* setup key */ + if ((err = rc6_setup(tests[x].key, tests[x].keylen, 0, &key)) != CRYPT_OK) { + return err; + } + + /* encrypt and decrypt */ + rc6_ecb_encrypt(tests[x].pt, tmp[0], &key); + rc6_ecb_decrypt(tmp[0], tmp[1], &key); + + /* compare */ + if (memcmp(tmp[0], tests[x].ct, 16) || memcmp(tmp[1], tests[x].pt, 16)) { +#if 0 + printf("\n\nFailed test %d\n", x); + if (memcmp(tmp[0], tests[x].ct, 16)) { + printf("Ciphertext: "); + for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]); + printf("\nExpected : "); + for (y = 0; y < 16; y++) printf("%02x ", tests[x].ct[y]); + printf("\n"); + } + if (memcmp(tmp[1], tests[x].pt, 16)) { + printf("Plaintext: "); + for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]); + printf("\nExpected : "); + for (y = 0; y < 16; y++) printf("%02x ", tests[x].pt[y]); + printf("\n"); + } +#endif + 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 < 16; y++) tmp[0][y] = 0; + for (y = 0; y < 1000; y++) rc6_ecb_encrypt(tmp[0], tmp[0], &key); + for (y = 0; y < 1000; y++) rc6_ecb_decrypt(tmp[0], tmp[0], &key); + for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; + } + return CRYPT_OK; + #endif +} + +/** Terminate the context + @param skey The scheduled key +*/ +void rc6_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 rc6_keysize(int *keysize) +{ + LTC_ARGCHK(keysize != NULL); + if (*keysize < 8) { + return CRYPT_INVALID_KEYSIZE; + } else if (*keysize > 128) { + *keysize = 128; + } + return CRYPT_OK; +} + +#endif /*RC6*/ + + + +/* $Source: /cvs/libtom/libtomcrypt/src/ciphers/rc6.c,v $ */ +/* $Revision: 1.7 $ */ +/* $Date: 2005/05/05 14:35:58 $ */ |