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| 1 | +//! |
| 2 | +//! Key hashing utilities for enhanced privacy in UTXO management. |
| 3 | +//! |
| 4 | +//! This module provides functionality to create addresses from hashed public keys, |
| 5 | +//! improving privacy by not exposing the actual public key until the UTXO is spent. |
| 6 | +
|
| 7 | +use crate::imports::*; |
| 8 | +use kaspa_addresses::{Address, Prefix, Version}; |
| 9 | +use kaspa_hashes::{Hash, Hasher, TransactionHash}; |
| 10 | +use secp256k1::PublicKey; |
| 11 | + |
| 12 | +/// Creates a hash of a public key for use in UTXO addresses |
| 13 | +pub fn hash_public_key(public_key: &PublicKey) -> Hash { |
| 14 | + TransactionHash::hash(&public_key.serialize()) |
| 15 | +} |
| 16 | + |
| 17 | +/// Creates an address from a hashed public key |
| 18 | +pub fn create_hashed_address(public_key: &PublicKey, prefix: Prefix) -> Result<Address> { |
| 19 | + let key_hash = hash_public_key(public_key); |
| 20 | + let address = Address::new(prefix, Version::PubKeyHash, &key_hash.as_bytes()); |
| 21 | + Ok(address) |
| 22 | +} |
| 23 | + |
| 24 | +/// Creates an address from a hashed public key for Schnorr signatures |
| 25 | +pub fn create_hashed_schnorr_address(public_key: &secp256k1::XOnlyPublicKey, prefix: Prefix) -> Result<Address> { |
| 26 | + let key_hash = TransactionHash::hash(&public_key.serialize()); |
| 27 | + let address = Address::new(prefix, Version::PubKeyHash, &key_hash.as_bytes()); |
| 28 | + Ok(address) |
| 29 | +} |
| 30 | + |
| 31 | +/// Derives the next change address using hashed public key |
| 32 | +pub fn derive_next_change_address_hashed(public_key: &PublicKey, change_index: u32, prefix: Prefix) -> Result<Address> { |
| 33 | + // We'll use a simple derivation by hashing the public key with the index |
| 34 | + // In a real implementation, this would use proper HD derivation |
| 35 | + let mut data = public_key.serialize().to_vec(); |
| 36 | + data.extend_from_slice(&change_index.to_le_bytes()); |
| 37 | + let key_hash = TransactionHash::hash(&data); |
| 38 | + let address = Address::new(prefix, Version::PubKeyHash, &key_hash.as_bytes()); |
| 39 | + Ok(address) |
| 40 | +} |
| 41 | + |
| 42 | +#[cfg(test)] |
| 43 | +mod tests { |
| 44 | + use super::*; |
| 45 | + use secp256k1::Secp256k1; |
| 46 | + |
| 47 | + #[test] |
| 48 | + fn test_hash_public_key() { |
| 49 | + let secp = Secp256k1::new(); |
| 50 | + let (_, public_key) = secp.generate_keypair(&mut secp256k1::rand::thread_rng()); |
| 51 | + |
| 52 | + let hash1 = hash_public_key(&public_key); |
| 53 | + let hash2 = hash_public_key(&public_key); |
| 54 | + |
| 55 | + // Same public key should produce same hash |
| 56 | + assert_eq!(hash1, hash2); |
| 57 | + |
| 58 | + // Hash should be different from the original public key |
| 59 | + assert_ne!(hash1.as_bytes(), &public_key.serialize()[..]); |
| 60 | + } |
| 61 | + #[test] |
| 62 | + fn test_create_hashed_address_compare() -> Result<()> { |
| 63 | + println!("\n=== Key Hashing for Enhanced Privacy Example ==="); |
| 64 | + |
| 65 | + let secp = Secp256k1::new(); |
| 66 | + let (_secret_key, public_key) = secp.generate_keypair(&mut secp256k1::rand::thread_rng()); |
| 67 | + |
| 68 | + // Create regular address (exposes public key) |
| 69 | + let regular_address = Address::new(Prefix::Testnet, Version::PubKeyECDSA, &public_key.serialize()); |
| 70 | + println!("Regular Address (exposes public key): {}", regular_address); |
| 71 | + |
| 72 | + // Create hashed address (hides public key until spent) |
| 73 | + let hashed_address = create_hashed_address(&public_key, Prefix::Testnet)?; |
| 74 | + println!("Hashed Address (privacy enhanced): {}", hashed_address); |
| 75 | + |
| 76 | + // Demonstrate that the hashed address doesn't reveal the public key |
| 77 | + println!("Public key: {}", faster_hex::hex_string(&public_key.serialize())); |
| 78 | + println!("Hashed address payload: {}", faster_hex::hex_string(hashed_address.payload.as_slice())); |
| 79 | + |
| 80 | + // Show that different public keys produce different hashed addresses |
| 81 | + let (_, another_public_key) = secp.generate_keypair(&mut secp256k1::rand::thread_rng()); |
| 82 | + let another_hashed_address = create_hashed_address(&another_public_key, Prefix::Testnet)?; |
| 83 | + println!("Another hashed address: {}", another_hashed_address); |
| 84 | + |
| 85 | + assert_eq!(another_hashed_address.version, Version::PubKeyHash); |
| 86 | + assert_eq!(another_hashed_address.prefix, Prefix::Testnet); |
| 87 | + assert_eq!(another_hashed_address.payload.len(), 32); |
| 88 | + |
| 89 | + assert_eq!(hashed_address.version, Version::PubKeyHash); |
| 90 | + assert_eq!(hashed_address.prefix, Prefix::Testnet); |
| 91 | + assert_eq!(hashed_address.payload.len(), 32); |
| 92 | + |
| 93 | + assert_ne!(hashed_address, another_hashed_address); |
| 94 | + println!("✓ Different public keys produce different hashed addresses"); |
| 95 | + |
| 96 | + Ok(()) |
| 97 | + } |
| 98 | + |
| 99 | + #[test] |
| 100 | + fn test_derive_next_change_address() { |
| 101 | + let secp = Secp256k1::new(); |
| 102 | + let (_, public_key) = secp.generate_keypair(&mut secp256k1::rand::thread_rng()); |
| 103 | + |
| 104 | + let address1 = derive_next_change_address_hashed(&public_key, 0, Prefix::Mainnet).unwrap(); |
| 105 | + let address2 = derive_next_change_address_hashed(&public_key, 1, Prefix::Mainnet).unwrap(); |
| 106 | + |
| 107 | + // Different indices should produce different addresses |
| 108 | + assert_ne!(address1, address2); |
| 109 | + |
| 110 | + // Both should be PubKeyHash addresses |
| 111 | + assert_eq!(address1.version, Version::PubKeyHash); |
| 112 | + assert_eq!(address2.version, Version::PubKeyHash); |
| 113 | + } |
| 114 | +} |
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