PUTU32
PUTU32(ciphertext, tmp[0]);
PUTU32(ciphertext+4, tmp[1]);
PUTU32(ciphertext+8, tmp[2]);
PUTU32(ciphertext+12, tmp[3]);
PUTU32(plaintext, tmp[0]);
PUTU32(plaintext+4, tmp[1]);
PUTU32(plaintext+8, tmp[2]);
PUTU32(plaintext+12, tmp[3]);