entropy

Documentation

Overview

Package entropy contains functions for checking the entropy of given data

Index

• Constants
• func CalculateShannon(data []byte) float64
• func Check(b []byte) (bool, int)

Examples

• CalculateShannon

Constants

const (
	Base64Threshold = 4.5
	HexThreshold    = 3.0
)

Define entropy thresholds over which a string is considered complex enough to be a potential key

Functions

func CalculateShannon

func CalculateShannon(data []byte) float64

CalculateShannon calculates the shannon entropy for a block of data - http://blog.dkbza.org/2007/05/scanning-data-for-entropy-anomalies.html

Example

package main

import (
	"fmt"

	"github.com/ONSdigital/git-diff-check/entropy"
)

func main() {
	password := []byte("verysecret")
	if entropy.CalculateShannon(password) < entropy.Base64Threshold {
		fmt.Println("Password not complex enough!")
	}
}

func Check

func Check(b []byte) (bool, int)

Check searches through a given block of data to attempt to identify high entropy blocks. Returns true and number of matching strings if found