void serpent_enc(void* buffer, const serpent_ctx_t* ctx){
uint8_t i;
for(i=0; i<31; ++i){
memxor(buffer, ctx->k[i], 16);
sbox128(buffer, i);
void serpent_enc(void* buffer, const serpent_ctx_t* ctx){
uint8_t i;
for(i=0; i<31; ++i){
memxor(buffer, ctx->k[i], 16);
sbox128(buffer, i);