5 const struct _cipher_descriptor xtea_desc =
17 int xtea_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
19 unsigned long x, sum, K[4];
22 _ARGCHK(skey != NULL);
26 return CRYPT_INVALID_KEYSIZE;
29 if (num_rounds != 0 && num_rounds != 32) {
30 return CRYPT_INVALID_ROUNDS;
37 LOAD32L(K[3], key+12);
39 for (x = sum = 0; x < 32; x++) {
40 skey->xtea.A[x] = (sum + K[sum&3]) & 0xFFFFFFFFUL;
41 sum = (sum + 0x9E3779B9UL) & 0xFFFFFFFFUL;
42 skey->xtea.B[x] = (sum + K[(sum>>11)&3]) & 0xFFFFFFFFUL;
46 zeromem(&K, sizeof(K));
52 void xtea_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key)
63 for (r = 0; r < 32; r += 4) {
64 y = (y + ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r])) & 0xFFFFFFFFUL;
65 z = (z + ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r])) & 0xFFFFFFFFUL;
67 y = (y + ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r+1])) & 0xFFFFFFFFUL;
68 z = (z + ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r+1])) & 0xFFFFFFFFUL;
70 y = (y + ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r+2])) & 0xFFFFFFFFUL;
71 z = (z + ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r+2])) & 0xFFFFFFFFUL;
73 y = (y + ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r+3])) & 0xFFFFFFFFUL;
74 z = (z + ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r+3])) & 0xFFFFFFFFUL;
80 void xtea_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key)
91 for (r = 31; r >= 0; r -= 4) {
92 z = (z - ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r])) & 0xFFFFFFFFUL;
93 y = (y - ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r])) & 0xFFFFFFFFUL;
95 z = (z - ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r-1])) & 0xFFFFFFFFUL;
96 y = (y - ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r-1])) & 0xFFFFFFFFUL;
98 z = (z - ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r-2])) & 0xFFFFFFFFUL;
99 y = (y - ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r-2])) & 0xFFFFFFFFUL;
101 z = (z - ((((y<<4)^(y>>5)) + y) ^ key->xtea.B[r-3])) & 0xFFFFFFFFUL;
102 y = (y - ((((z<<4)^(z>>5)) + z) ^ key->xtea.A[r-3])) & 0xFFFFFFFFUL;
113 static const unsigned char key[16] =
114 { 0x78, 0x56, 0x34, 0x12, 0xf0, 0xcd, 0xcb, 0x9a,
115 0x48, 0x37, 0x26, 0x15, 0xc0, 0xbf, 0xae, 0x9d };
116 static const unsigned char pt[8] =
117 { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 };
118 static const unsigned char ct[8] =
119 { 0x75, 0xd7, 0xc5, 0xbf, 0xcf, 0x58, 0xc9, 0x3f };
120 unsigned char tmp[2][8];
124 if ((err = xtea_setup(key, 16, 0, &skey)) != CRYPT_OK) {
127 xtea_ecb_encrypt(pt, tmp[0], &skey);
128 xtea_ecb_decrypt(tmp[0], tmp[1], &skey);
130 if (memcmp(tmp[0], ct, 8) != 0 || memcmp(tmp[1], pt, 8) != 0) {
131 return CRYPT_FAIL_TESTVECTOR;
138 int xtea_keysize(int *desired_keysize)
140 _ARGCHK(desired_keysize != NULL);
141 if (*desired_keysize < 16) {
142 return CRYPT_INVALID_KEYSIZE;
144 *desired_keysize = 16;