README

passwd-strength

Simple password strength calculator. It computes the number of bits of entropy of a given password and also checks the password against a list of over 30,000 common passwords.

Installation

npm install --save passwd-strength

API

passwdStrength(passwd)

Parameters:

passwd - the password to test.

Returns:

The number of bits of entropy (floating point number). Higher is better. 0 is returned when a common passwords such as abc123, password, etc is encountered.

Example

"use strict";

var passwdStrength = require('passwd-strength');

app.post('/register', function (req, res, next) {
    if (passwdStrength(req.body.passwd) < 29) {
        next(new Error('Password not strong enough. Add entropy by increasing the password length and including upper case letters, lower case letters, digits, and punctuation.'));
        return;
    }
    // ...
});

Tips

RFC4086 has a section on Password Generation that explains how to determine how much entropy you need.

License

See LICENSE.md

Usage no npm install needed!