/* CLX-128: 128-bit key, 96-bit IV, 160-bit state Reference implementation of CLX-128 on 32-bit processor. The state consists of five 32-bit registers state[4] || state[3] || state[2] || state[1] || state[0] Implemented by Hongjun Wu */ #include #include #include "crypto_aead.h" #define FrameBitsIV 0x10 #define FrameBitsAD 0x30 #define FrameBitsPC 0x50 //Framebits for plaintext/ciphertext #define FrameBitsFinalization 0x70 #define NROUND1 384 #define NROUND2 1152 /*no-optimized state update function*/ void state_update(unsigned int *state, unsigned int number_of_steps) { unsigned int i; unsigned int t1, t2, t3, t4, feedback; for (i = 0; i < number_of_steps; i = i + 32) { t1 = (state[1] >> 3) | (state[2] << 29); //35 = 1*32 + 3 t2 = (state[2] >> 29) | (state[3] << 3); //93 = 2*32 + 29 t3 = (state[3] >> 10) | (state[4] << 22); //106 = 3*32 + 10 t4 = (state[3] >> 31) | (state[4] << 1); //127 = 3*32 + 31 feedback = state[0] ^ t1 ^ (~(t2 & t3)) ^ t4; // shift 32 bit positions state[0] = state[1]; state[1] = state[2]; state[2] = state[3]; state[3] = state[4]; state[4] = feedback; } } // The initialization // The input to initialization is the key and IV; void initialization(const unsigned char *key, const unsigned char *iv, unsigned int *state) { int i; //initialize the state as key state[0] = 0x80000000; for (i = 0; i < 4; i++) state[i+1] = ((unsigned int*)key)[i]; //update the state state_update(state, NROUND2); //introduce iv into the state for (i = 0; i < 3; i++) { state[2] ^= FrameBitsIV; state_update(state, NROUND1); state[4] ^= ((unsigned int*)iv)[i]; } } //process the associated data void process_ad(const unsigned char *ad, unsigned long long adlen, unsigned int *state) { unsigned long long i; unsigned int j; for (i = 0; i < (adlen >> 2); i++) { state[2] ^= FrameBitsAD; state_update(state, NROUND1); state[4] ^= ((unsigned int*)ad)[i]; } // if adlen is not a multiple of 4, we process the remaining bytes if ((adlen & 3) > 0) { state[2] ^= FrameBitsAD; state_update(state, NROUND1); for (j = 0; j < (adlen & 3); j++) ((unsigned char*)state)[16 + j] ^= ad[(i << 2) + j]; state[2] ^= adlen & 3; } } //encrypt a message int crypto_aead_encrypt( unsigned char *c,unsigned long long *clen, const unsigned char *m,unsigned long long mlen, const unsigned char *ad,unsigned long long adlen, const unsigned char *nsec, const unsigned char *npub, const unsigned char *k ) { unsigned long long i; unsigned int j; unsigned char mac[8]; unsigned int state[5]; //initialization stage initialization(k, npub, state); //process the associated data process_ad(ad, adlen, state); //process the plaintext for (i = 0; i < (mlen >> 2); i++) { state[2] ^= FrameBitsPC; state_update(state, NROUND2); state[4] ^= ((unsigned int*)m)[i]; ((unsigned int*)c)[i] = state[4]; } // if mlen is not a multiple of 4, we process the remaining bytes if ((mlen & 3) > 0) { state[2] ^= FrameBitsPC; state_update(state, NROUND2); for (j = 0; j < (mlen & 3); j++) { ((unsigned char*)state)[16 + j] ^= m[(i << 2) + j]; c[(i << 2) + j] = ((unsigned char*)state)[16 + j]; } state[2] ^= (mlen & 3); } //finalization stage, we assume that the tag length is a multiple of bytes for (i = 0; i < 2; i++) { state[2] ^= FrameBitsFinalization; state_update(state, NROUND2); ((unsigned int*)mac)[i] = state[4]; } *clen = mlen + 8; memcpy(c+mlen, mac, 8); return 0; } //decrypt a message int crypto_aead_decrypt( unsigned char *m,unsigned long long *mlen, unsigned char *nsec, const unsigned char *c,unsigned long long clen, const unsigned char *ad,unsigned long long adlen, const unsigned char *npub, const unsigned char *k ) { unsigned long long i; unsigned int j, check = 0; unsigned char mac[8]; unsigned int state[5]; *mlen = clen - 8; //initialization stage initialization(k, npub, state); //process the associated data process_ad(ad, adlen, state); //process the ciphertext for (i = 0; i < (*mlen >> 2); i++) { state[2] ^= FrameBitsPC; state_update(state, NROUND2); ((unsigned int*)m)[i] = state[4] ^ ((unsigned int*)c)[i]; state[4] = ((unsigned int*)c)[i]; } // if mlen is not a multiple of 4, we process the remaining bytes if ((*mlen & 3) > 0) { state[2] ^= FrameBitsPC; state_update(state, NROUND2); for (j = 0; j < (*mlen & 3); j++) { m[(i << 2) + j] = ((unsigned char*)state)[16 + j] ^ c[(i << 2) + j]; ((unsigned char*)state)[16 + j] = c[(i << 2) + j]; } state[2] ^= *mlen & 3; } //finalization stage, we assume that the tag length is a multiple of bytes for (i = 0; i < 2; i++) { state[2] ^= FrameBitsFinalization; state_update(state, NROUND2); ((unsigned int*)mac)[i] = state[4]; } for (i = 0; i < 8; i++) check |= (mac[i] ^ c[clen - 8 + i]); if (check == 0) return 0; else return -1; }