Simple Password Exponential Key Exchange for Node.js. Resistant to MITM, unlike vanilla Diffie-Hellman


An incredibly simple balanced password-authenticated key exchange (PAKE) for Node.js.

This library is an implementation of SPEKE. Meant to reflect Node.js crypto's Diffie-Hellman API.

// Our password. 
var password = 'keyboardcat';
// Prepares an object for both Alice and Bob, with a prime value set. 
var alice = SPEKE.getSPEKE('modp5');
var bob = SPEKE.getSPEKE('modp5');
// Initialize the generator, based on the password, as well as create the 
// public and private keys. 
// Compute the shared secret, with Alice using Bob's public key, and Bob using 
// Alice's public key. 
var alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
var bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
// We should now have the same shared secret. 
assert(alice_secret.length > 1);
assert(alice_secret === bob_secret);

The API is 100% compatible with Node.js Crypto's Diffie-Hellman API, except that the generateKeys method absolutely requires a password as the first parameter, and the second parameter is an optional encoding type, which can either be set to 'binary', 'hex', or 'base64'. At the absence of the latter parameter, a buffer is returned for the public key.