Generates a cryptographically strong pseudo-random key for two-factor authentication. The key is a base32 encoded string containing 16 characters (10 bytes decoded).
The callback has the signature callback(err, key) where key is the random string if err is null.
var genKey = require('otp-key');
genKey(function (err, key) {
// key = 'JBSWY3DPEHPK3PXP'
});