Hash_bytes
unsigned char x[Hash_bytes * 2];
for (i = 0; i < Hash_bytes; ++i) x[Hash_bytes + i] = cache[i];
unsigned char x[Hash_bytes + crypto_kem_sntrup761_CIPHERTEXTBYTES];
for (i = 0; i < crypto_kem_sntrup761_CIPHERTEXTBYTES; ++i) x[Hash_bytes + i] = z[i];
unsigned char r_enc[Small_bytes], cache[Hash_bytes];