integrity.h

#ifndef INTEGRITY_H
#define INTEGRITY_H

#include <stdint.h>   // for uint64_t, uint8_t
#include <stdio.h>    // for sprintf (used in to_hex)
#include <string.h>   // for strlen

// -------------------------------------------------------
// Converts raw hash bytes to a printable hex string
// Example: [0xAB, 0x4F] -> "ab4f"
// -------------------------------------------------------
void to_hex(const unsigned char *hash, int len, char *output);

// -------------------------------------------------------
// Custom Key-Mixed Rolling Hash Function
// -------------------------------------------------------
// Parameters:
//   data      - input data (binary data to hash)
//   datalen   - length of input data in bytes
//   key       - secret key (used as dynamic modifier)
//   hash      - output buffer for hash bytes
//   hash_len  - number of hash bytes to generate (e.g., 8, 16)
//
// Description:
//   - Uses the key to alter each round of hashing.
//   - Introduces feedback, shifts, and XOR to increase diffusion.
//   - Produces consistent but unique hash for each data-key pair.
// -------------------------------------------------------
void key_mixed_rolling_hash(const char *data,
                            int datalen,
                            const char *key,
                            unsigned char *hash,
                            int hash_len);

#endif // INTEGRITY_H