299 lines
8.5 KiB
C
299 lines
8.5 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*
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* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
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*/
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/* RC6 code by Tom St Denis */
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#include "mycrypt.h"
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#ifdef RC6
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const struct _cipher_descriptor rc6_desc =
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{
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"rc6",
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3,
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8, 128, 16, 20,
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&rc6_setup,
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&rc6_ecb_encrypt,
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&rc6_ecb_decrypt,
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&rc6_test,
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&rc6_keysize
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};
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static const ulong32 stab[44] = {
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0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL,
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0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL,
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0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL,
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0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL,
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0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL,
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0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL };
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#ifdef CLEAN_STACK
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static int _rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
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#else
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int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
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#endif
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{
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ulong32 L[64], S[50], A, B, i, j, v, s, l;
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_ARGCHK(key != NULL);
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_ARGCHK(skey != NULL);
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/* test parameters */
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if (num_rounds != 0 && num_rounds != 20) {
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return CRYPT_INVALID_ROUNDS;
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}
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/* key must be between 64 and 1024 bits */
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if (keylen < 8 || keylen > 128) {
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return CRYPT_INVALID_KEYSIZE;
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}
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/* copy the key into the L array */
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for (A = i = j = 0; i < (ulong32)keylen; ) {
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A = (A << 8) | ((ulong32)(key[i++] & 255));
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if (!(i & 3)) {
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L[j++] = BSWAP(A);
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A = 0;
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}
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}
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/* handle odd sized keys */
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if (keylen & 3) {
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A <<= (8 * (4 - (keylen&3)));
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L[j++] = BSWAP(A);
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}
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/* setup the S array */
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XMEMCPY(S, stab, 44 * sizeof(stab[0]));
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/* mix buffer */
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s = 3 * MAX(44, j);
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l = j;
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for (A = B = i = j = v = 0; v < s; v++) {
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A = S[i] = ROL(S[i] + A + B, 3);
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B = L[j] = ROL(L[j] + A + B, (A+B));
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if (++i == 44) { i = 0; }
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if (++j == l) { j = 0; }
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}
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/* copy to key */
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for (i = 0; i < 44; i++) {
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skey->rc6.K[i] = S[i];
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}
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return CRYPT_OK;
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}
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#ifdef CLEAN_STACK
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int rc6_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
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{
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int x;
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x = _rc6_setup(key, keylen, num_rounds, skey);
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burn_stack(sizeof(ulong32) * 122);
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return x;
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}
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#endif
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#ifdef CLEAN_STACK
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static void _rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
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#else
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void rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
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#endif
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{
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ulong32 a,b,c,d,t,u, *K;
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int r;
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_ARGCHK(key != NULL);
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_ARGCHK(pt != NULL);
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_ARGCHK(ct != NULL);
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LOAD32L(a,&pt[0]);LOAD32L(b,&pt[4]);LOAD32L(c,&pt[8]);LOAD32L(d,&pt[12]);
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b += key->rc6.K[0];
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d += key->rc6.K[1];
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#define RND(a,b,c,d) \
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t = (b * (b + b + 1)); t = ROL(t, 5); \
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u = (d * (d + d + 1)); u = ROL(u, 5); \
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a = ROL(a^t,u) + K[0]; \
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c = ROL(c^u,t) + K[1]; K += 2;
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K = key->rc6.K + 2;
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for (r = 0; r < 20; r += 4) {
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RND(a,b,c,d);
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RND(b,c,d,a);
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RND(c,d,a,b);
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RND(d,a,b,c);
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}
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#undef RND
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a += key->rc6.K[42];
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c += key->rc6.K[43];
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STORE32L(a,&ct[0]);STORE32L(b,&ct[4]);STORE32L(c,&ct[8]);STORE32L(d,&ct[12]);
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}
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#ifdef CLEAN_STACK
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void rc6_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
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{
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_rc6_ecb_encrypt(pt, ct, key);
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burn_stack(sizeof(ulong32) * 6 + sizeof(int));
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}
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#endif
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#ifdef CLEAN_STACK
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static void _rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
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#else
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void rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
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#endif
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{
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ulong32 a,b,c,d,t,u, *K;
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int r;
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_ARGCHK(key != NULL);
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_ARGCHK(pt != NULL);
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_ARGCHK(ct != NULL);
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LOAD32L(a,&ct[0]);LOAD32L(b,&ct[4]);LOAD32L(c,&ct[8]);LOAD32L(d,&ct[12]);
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a -= key->rc6.K[42];
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c -= key->rc6.K[43];
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#define RND(a,b,c,d) \
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t = (b * (b + b + 1)); t = ROL(t, 5); \
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u = (d * (d + d + 1)); u = ROL(u, 5); \
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c = ROR(c - K[1], t) ^ u; \
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a = ROR(a - K[0], u) ^ t; K -= 2;
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K = key->rc6.K + 40;
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for (r = 0; r < 20; r += 4) {
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RND(d,a,b,c);
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RND(c,d,a,b);
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RND(b,c,d,a);
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RND(a,b,c,d);
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}
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#undef RND
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b -= key->rc6.K[0];
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d -= key->rc6.K[1];
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STORE32L(a,&pt[0]);STORE32L(b,&pt[4]);STORE32L(c,&pt[8]);STORE32L(d,&pt[12]);
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}
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#ifdef CLEAN_STACK
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void rc6_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
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{
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_rc6_ecb_decrypt(ct, pt, key);
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burn_stack(sizeof(ulong32) * 6 + sizeof(int));
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}
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#endif
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int rc6_test(void)
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{
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#ifndef LTC_TEST
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return CRYPT_NOP;
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#else
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static const struct {
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int keylen;
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unsigned char key[32], pt[16], ct[16];
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} tests[] = {
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{
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16,
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{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
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0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
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0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
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{ 0x52, 0x4e, 0x19, 0x2f, 0x47, 0x15, 0xc6, 0x23,
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0x1f, 0x51, 0xf6, 0x36, 0x7e, 0xa4, 0x3f, 0x18 }
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},
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{
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24,
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{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
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0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
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0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
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{ 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
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0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
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{ 0x68, 0x83, 0x29, 0xd0, 0x19, 0xe5, 0x05, 0x04,
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0x1e, 0x52, 0xe9, 0x2a, 0xf9, 0x52, 0x91, 0xd4 }
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},
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{
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32,
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{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
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0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67, 0x78,
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0x89, 0x9a, 0xab, 0xbc, 0xcd, 0xde, 0xef, 0xf0,
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0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe },
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{ 0x02, 0x13, 0x24, 0x35, 0x46, 0x57, 0x68, 0x79,
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0x8a, 0x9b, 0xac, 0xbd, 0xce, 0xdf, 0xe0, 0xf1 },
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{ 0xc8, 0x24, 0x18, 0x16, 0xf0, 0xd7, 0xe4, 0x89,
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0x20, 0xad, 0x16, 0xa1, 0x67, 0x4e, 0x5d, 0x48 }
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}
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};
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unsigned char tmp[2][16];
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int x, y, err;
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symmetric_key key;
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for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
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/* setup key */
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if ((err = rc6_setup(tests[x].key, tests[x].keylen, 0, &key)) != CRYPT_OK) {
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return err;
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}
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/* encrypt and decrypt */
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rc6_ecb_encrypt(tests[x].pt, tmp[0], &key);
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rc6_ecb_decrypt(tmp[0], tmp[1], &key);
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/* compare */
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if (memcmp(tmp[0], tests[x].ct, 16) || memcmp(tmp[1], tests[x].pt, 16)) {
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#if 0
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printf("\n\nFailed test %d\n", x);
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if (memcmp(tmp[0], tests[x].ct, 16)) {
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printf("Ciphertext: ");
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for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]);
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printf("\nExpected : ");
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for (y = 0; y < 16; y++) printf("%02x ", tests[x].ct[y]);
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printf("\n");
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}
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if (memcmp(tmp[1], tests[x].pt, 16)) {
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printf("Plaintext: ");
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for (y = 0; y < 16; y++) printf("%02x ", tmp[0][y]);
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printf("\nExpected : ");
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for (y = 0; y < 16; y++) printf("%02x ", tests[x].pt[y]);
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printf("\n");
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}
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#endif
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return CRYPT_FAIL_TESTVECTOR;
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}
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/* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
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for (y = 0; y < 16; y++) tmp[0][y] = 0;
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for (y = 0; y < 1000; y++) rc6_ecb_encrypt(tmp[0], tmp[0], &key);
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for (y = 0; y < 1000; y++) rc6_ecb_decrypt(tmp[0], tmp[0], &key);
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for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
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}
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return CRYPT_OK;
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#endif
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}
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int rc6_keysize(int *desired_keysize)
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{
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_ARGCHK(desired_keysize != NULL);
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if (*desired_keysize < 8) {
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return CRYPT_INVALID_KEYSIZE;
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} else if (*desired_keysize > 128) {
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*desired_keysize = 128;
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}
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return CRYPT_OK;
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}
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#endif /*RC6*/
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