void encrypt(WORD *plainTxt, WORD *cipherTxt) {
WORD A = plainTxt[0] + S[0];
WORD B = plainTxt[1] + S[1];
int i;
for (i = 1; i <= r; i++) {
A = ROTATE_L(A^B, B) + S[2*i];
B = ROTATE_L(B^A, A) + S[2*i+1];
}
cipherTxt[0] = A;
cipherTxt[1] = B;
}
void setup(unsigned char *K) {
WORD C, D, L[c]; /* L will be zeroed */
int u = w/8; /* u = number of bytes per word */
int i, j, h;
// Copy secret key into L
//for(i = b-1, L[c-1]=0; i != -1; --i)
for(i = b-1; i != -1; --i)
L[i/u] = (L[i/u] << 8) + K[i];
//L[i/u] = ROTATE_L(L[i/u], 8) + K[i];
// Initialize Array S
for (S[0] = P, i = 1; i < t; ++i)
S[i] = S[i-1] + Q;
// Mix in Secret Key
for (i=j=h=C=D=0; h < 3*t; ++h, i=(i+1)%t, j=(j+1)%c) {
C = S[i] = ROTATE_L(S[i] + (C + D), 3);
D = L[j] = ROTATE_L(L[j] + (C + D), (C+D));
}
}
int main(int argc, unsigned char **argv) {
char byte;
int cnt, i, j;
WORD plainTxt[2] = {0,0};
WORD cipherTxt[2] = {0,0};
#ifdef DEBUG
(isBigEndian()) ? printf("*** Big Endian ***\n") :
printf("*** Little Endian ***\n\n");
#endif
// Some basic error checking
if (argc < 2) {
printf("Key not supplied... Exiting!\n");
exit(1);
}
if (strlen(argv[1]) > 2*b) {
printf("Key exceeded %d hex characters... Exiting!\n", 2*b);
exit(1);
}
setHexKey(argv[1]);
#if DEBUG
printf("[HEX KEY] 0x: ");
for (i=0; i < b; i++) {
printf("%02x ", K[i]);
}
puts("\n");
#endif
setup(K);
cnt = i = j = 0;
while ( (byte = getchar()) != EOF ) {
++cnt;
// i in interval [0,3]; Alternate plainTxt index, j, every 4 characters
if (i == 4) {
i = 0;
j = (j == 0) ? 1 : 0;
}
plainTxt[j] += (unsigned int)ROTATE_L(byte, i*8);
// Encrypt after every 8 characters
if (cnt % 8 == 0) {
encrypt(plainTxt, cipherTxt);
printf("[CIPHER HEX] %.8X %.8X\n", cipherTxt[0], cipherTxt[1]);
#if 1 // Decryption
decrypt(cipherTxt, plainTxt);
printf("[PLAIN HEX ] %.8X %.8X\n\n", plainTxt[0], plainTxt[1]);
#endif
plainTxt[0] = 0;
plainTxt[1] = 0;
}
++i;
}
// Encrypt any remaining characters
if (cnt % 8 != 0) {
encrypt(plainTxt, cipherTxt);
printf("[CIPHER HEX] %.8X %.8X\n", cipherTxt[0], cipherTxt[1]);
decrypt(cipherTxt, plainTxt);
printf("[PLAIN HEX ] %.8X %.8X\n\n", plainTxt[0], plainTxt[1]);
}
#if DEBUG
printf("[cnt = %d : cnt (mod 8) = %d ]\n", cnt, cnt%8);
#endif
return 0;
}
(x2) = (x2) ^ (round_key)[2]; \
(x3) = (x3) ^ (round_key)[3]
void serpent_key_expand(uint32_t* key, uint32_t key_length, uint32_t* round_key){
uint32_t i;
if (key_length < SERPENT_KEY_MAX_NB_BIT){
key[key_length >> 5] &= ~(0xffffffff << (key_length & 0x0000001f));
key[key_length >> 5] |= 0x00000001 << (key_length & 0x0000001f);
for (i = (key_length >> 5) + 1; i < SERPENT_KEY_MAX_NB_DWORD; i++){
key[i] = 0;
}
}
round_key[0] = ROTATE_L(key[0] ^ key[3] ^ key[5] ^ key[7] ^ SERPENT_GOLDEN_RATIO ^ 0, 11);
round_key[1] = ROTATE_L(key[1] ^ key[4] ^ key[6] ^ round_key[0] ^ SERPENT_GOLDEN_RATIO ^ 1, 11);
round_key[2] = ROTATE_L(key[2] ^ key[5] ^ key[7] ^ round_key[1] ^ SERPENT_GOLDEN_RATIO ^ 2, 11);
round_key[3] = ROTATE_L(key[3] ^ key[6] ^ round_key[0] ^ round_key[2] ^ SERPENT_GOLDEN_RATIO ^ 3, 11);
round_key[4] = ROTATE_L(key[4] ^ key[7] ^ round_key[1] ^ round_key[3] ^ SERPENT_GOLDEN_RATIO ^ 4, 11);
round_key[5] = ROTATE_L(key[5] ^ round_key[0] ^ round_key[2] ^ round_key[4] ^ SERPENT_GOLDEN_RATIO ^ 5, 11);
round_key[6] = ROTATE_L(key[6] ^ round_key[1] ^ round_key[3] ^ round_key[5] ^ SERPENT_GOLDEN_RATIO ^ 6, 11);
round_key[7] = ROTATE_L(key[7] ^ round_key[2] ^ round_key[4] ^ round_key[6] ^ SERPENT_GOLDEN_RATIO ^ 7, 11);
for (i = 8; i < SERPENT_ROUND_KEY_NB_DWORD; i++){
round_key[i] = ROTATE_L(round_key[i - 8] ^ round_key[i - 5] ^ round_key[i - 3] ^ round_key[i - 1] ^ SERPENT_GOLDEN_RATIO ^ i, 11);
}
SBoxE3(round_key[0 ], round_key[1 ], round_key[2 ], round_key[3 ]);
SBoxE2(round_key[4 ], round_key[5 ], round_key[6 ], round_key[7 ]);
SBoxE1(round_key[8 ], round_key[9 ], round_key[10 ], round_key[11 ]);
