Decrypt Password Created by crypto.pbkdf2 Object

Question

I have the following code in javascript, running on NodeJs:

encryptPassword: function(password) {
    if (!password || !this.salt) return '';
    var salt = new Buffer(this.salt, 'base64');
    return crypto.pbkdf2Sync(password, salt, 10000, 64).toString('base64');
}

How can I implement the decrypt function? It can be in java or in javascript.

Thx!

Solution

PBKDF2 is a one-way hashing algorithm. It's not possible to decrypt the generated hash. You can read more about this here.

A one way hash performs a bunch of mathematical operations that transform input into a (mostly) unique output, called a digest. Because these operations are one way, you cannot ‘decrypt’ the output- you can’t turn a digest into the original input.

If you want to use PBKDF2 to store and compare passwords, you might be interested in the pbkdf2 library. It makes generation and comparison of passwords easy:

var pbkdf2 = require('pbkdf2');
var p = 'password';
var s = pbkdf2.generateSaltSync(32);
var pwd = pbkdf2.hashSync(p, s, 1, 20, 'sha256');
var bool = pbkdf2.compareSync(pwd, p, s, 1, 20, 'sha256');

Comments

[yonatan]

Thx. Compaing passwords is pretty easy without your code. We can just compare strings. As far as I understand it, using my function above on same two strings will return the same hashed password.