This package is a simple one-time-password generator. It supports both HOTP (according to RFC 4226 spec) and TOTP (according to RFC 6238 spec).
⚠️ It only supports 8-byte counters as of now, as per the spec.
Both HOTP and TOTP have been tested according to the RFC example values.
npm i -s @control/otp --no-optional
As a matter of fact, this package also has a CLI, which uses an optional dependency. If you're looking to use this programatically, you can skip that dependency.
npm i -g @control/otp
otp [id] [options]
When no ID and no options are provided, the list of saved configurations will be returned. To know more use:
otp -h
HOTP (HMAC One Time Password) is an algorithm to generate one-time-use passwords. These are generated according to a counter, which is supposed to change on every use (hence the one-time-use).
This library does not provide any mechanism to allow the counters to increment.
const { HOTP } = require('@control/otp');
const my_hotp = new HOTP({ algorithm: 'sha1', key: 'my_super_secret_key' });
const hotp_code = my_hotp.code({ counter: 25 });TOTP (Time-based One Time Password) follows the same pattern than HOTP. The main difference is that the HOTP counter is actually the number of time periods elapsed since a given time (usually Unix Epoch).
⚠️ This library assumes that the starting point is always Unix Epoch; it is, however, possible to configure
Contrary to HOTP however, TOTP does not need to increment a counter, since the counter is uniquely dependant on time (which, to make it clear, usually advances on its own).
const { TOTP } = require('@control/otp');
const my_totp = new TOTP({ algorithm: 'sha256', key: 'my_super_secret_key' });
// With a Date object
const totp_code = my_totp.code({ date: new Date('2022-04-09T14:33:00Z') });
// With a number of seconds since epoch
const totp_code = my_totp.code({ date: 1649507635 });As you can see, it is possible to pass the number of seconds since epoch, which essentially allows you to create a custom epoch, but it requires that you make the now - epoch difference yourself.