Function clockhash256_domain 

pub fn clockhash256_domain(domain: &[u8], data: &[u8]) -> [u8; 32]

Compute ClockHash-256 with custom domain separation.

This function provides domain separation by prepending the domain identifier followed by a null byte separator before hashing the actual data. This ensures that identical data produces different hashes when used in different domains, preventing cross-domain collision attacks.

Arguments

• domain - Custom domain identifier bytes (must be consistent for the same domain)
• data - The data to hash

Returns

A 32-byte array containing the domain-separated ClockHash-256 hash

Examples

Using custom domain tags:

let data = b"some data";

let domain1 = b"MY-APP-V1";
let domain2 = b"MY-APP-V2";

let hash1 = clockhash256_domain(domain1, data);
let hash2 = clockhash256_domain(domain2, data);

assert_ne!(hash1, hash2); // Different domains = different hashes

Custom domain vs no domain:

let data = b"test";
let custom_hash = clockhash256_domain(b"CUSTOM", data);
let plain_hash = clockhash256(data);

assert_ne!(custom_hash, plain_hash); // Domain separation works

Security Notes

• Domain identifiers should be unique and consistent within your application
• Never use the same domain for different purposes
• Domain separation is critical for maintaining hash function security properties