diff options
| -rw-r--r-- | src/lib.rs | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -75,6 +75,25 @@ pub fn find_single_byte_xor_encrypted_string (inputs: &[Vec<u8>]) -> Vec<u8> { return best_decrypted; } +fn hamming (bytes1: &[u8], bytes2: &[u8]) -> u64 { + count_bits(&fixed_xor(bytes1, bytes2)[..]) +} + +fn count_bits (bytes: &[u8]) -> u64 { + bytes.iter().map(|&c| { count_bits_byte(c) }).fold(0, |acc, n| acc + n) +} + +fn count_bits_byte (byte: u8) -> u64 { + (((byte & (0x01 << 0)) >> 0) + + ((byte & (0x01 << 1)) >> 1) + + ((byte & (0x01 << 2)) >> 2) + + ((byte & (0x01 << 3)) >> 3) + + ((byte & (0x01 << 4)) >> 4) + + ((byte & (0x01 << 5)) >> 5) + + ((byte & (0x01 << 6)) >> 6) + + ((byte & (0x01 << 7)) >> 7)) as u64 +} + fn crack_single_byte_xor_with_confidence (input: &[u8]) -> (u8, f64) { let mut min_diff = 100.0; let mut best_key = 0; @@ -112,3 +131,8 @@ fn crack_single_byte_xor_with_confidence (input: &[u8]) -> (u8, f64) { return (best_key, min_diff); } + +#[test] +fn test_hamming () { + assert_eq!(hamming(b"this is a test", b"wokka wokka!!!"), 37); +} |