TOTP++ Library

Library to generate Time-based One-Time Passwords.

Implements the Time-based One-Time Password algorithm specified in RFC 6238. Supports different time steps and it's compatible with tokens that uses the same standard (including software ones, like the Google Authenticator app).

Installation & usage:

Install the library using the Library Manager or manually in the \libraries folder of your IDE

First, store your private key into an array:

std::string hmacKey = "JBSWY3DPEHPK3PXP";

Then create a new instance of the TOTP class using one of the two available constructors:

TOTP totp = TOTP();

The first assumes a timeStep of 30 seconds, value used for example by the Google Authenticator app.

Two methods are available to get a TOTP passcode:

char *newCode = totp.getCode(key, 30, GMT);

The first accept a unix timestamp (number of seconds since Epoch), the second the number of "steps" since Epoch (that is seconds / timeStep) and it's useful to get a pool of values.

Thanks to:

• lucadentella, https://github.com/damico/TOTP-Arduino
• Jose Damico, https://github.com/damico/ARDUINO-OATH-TOKEN
• Peter Knight, https://github.com/Cathedrow/Cryptosuite
• Maniacbug, https://github.com/maniacbug/Cryptosuite