entropy

A Rust library for calculating Shannon entropy and metric entropy of byte sequences.

Installation

Add this to your Cargo.toml:

[dependencies]
entropy = "0.4"

Usage

use entropy::{shannon_entropy, metric_entropy};

// Calculate Shannon entropy (in bits)
let h = shannon_entropy("hello, world");
assert_eq!(h, 3.0220551);

// Works with byte slices too
let h = shannon_entropy(b"\x00\x01\x02\x03");

// Calculate metric entropy (shannon_entropy / input.len())
let m = metric_entropy("hello, world");
assert_eq!(m, 0.25183794);

What is Shannon Entropy?

Shannon entropy measures the average amount of information contained in a message, expressed in bits. For byte data:

Common Use Cases

• Cryptography - Measuring randomness of keys or random number generators
• Data compression - Estimating how compressible data is
• Malware analysis - Detecting packed or encrypted executables
• Password strength - Estimating password complexity