/* Red Pike cipher source code */ #include <stdint.h> typedef uint32_t word; #define CONST 0x9E3779B9 #define ROUNDS 16 #define ROTL(X, R) (((X) << ((R) & 31)) | ((X) >> (32 - ((R) & 31)))) #define ROTR(X, R) (((X) >> ((R) & 31)) | ((X) << (32 - ((R) & 31)))) void encrypt(word * x, const word * k) { unsigned int i; word rk0 = k[0]; word rk1 = k[1]; for (i = 0; i < ROUNDS; i++) { rk0 += CONST; rk1 -= CONST; x[0] ^= rk0; x[0] += x[1]; x[0] = ROTL(x[0], x[1]); x[1] = ROTR(x[1], x[0]); x[1] -= x[0]; x[1] ^= rk1; } rk0 = x[0]; x[0] = x[1]; x[1] = rk0; } void decrypt(word * x, const word * k) { word dk[2] = { k[1] - CONST * (ROUNDS + 1), k[0] + CONST * (ROUNDS + 1) }; encrypt(x, dk); }