org.passay.entropy

Class RandomPasswordEntropy

java.lang.Object

org.passay.entropy.RandomPasswordEntropy

All Implemented Interfaces:

Entropy

public class RandomPasswordEntropy
extends Object
implements Entropy

Entropy bits estimate defined in NIST SP-800-63-1 Randomly Selected Passwords. See PDF Publication A1. "Randomly Selected Passwords"

Author:

Middleware Services

Constructor Summary

Constructors

Constructor and Description
RandomPasswordEntropy(int alphaSize, int pwordSize) Creates a new random entropy estimate.

Method Summary

Modifier and Type	Method and Description
double	estimate() Returns the entropy bits of a randomly generated password given the size of the unique characters used (alphabetSize) and the size of the password.
static double	log2(double number) Returns the log base 2 of a given number.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RandomPasswordEntropy

public RandomPasswordEntropy(int alphaSize,
                             int pwordSize)

Creates a new random entropy estimate.

Parameters:

alphaSize - size of the alphabet used

pwordSize - size of the password

Method Detail

estimate

public double estimate()

Returns the entropy bits of a randomly generated password given the size of the unique characters used (alphabetSize) and the size of the password. See PDF Publication A1. "Randomly Selected Passwords"

Specified by:

estimate in interface Entropy

Returns:

estimated entropy bits given password properties

log2

public static double log2(double number)

Returns the log base 2 of a given number.

Parameters:

number - to get the log2 of

Returns:

log2 of number