One-Time Password Library

This library provides an implementation of HMAC-Based One-Time Password Algorithm (HOTP; RFC4226) and Time-Based One-Time Password Algorithm (HOTP; RFC6238). The Algorithm details can be referred at the following URLs.

Usage

To create new TOTP secret:

require "otp"

totp = OTP::TOTP.new
totp.new_secret  # create random secret
p totp.secret    #=> "YVMR2G7N4OAXGKFC" (BASE32-formated HMAC key)
p totp.algorithm #=> "SHA1" (HMAC algorithm; default SHA1)
p totp.digits    #=> 6 (number of password digits; default 6)
p totp.period    #=> 30 (time step period in second; default 30)
p totp.time      #=> nil (UNIX time by Time or Integer; nil for the current time)
p totp.password  #=> "123456" (password for the current time)

To verify given TOTP password:

require "otp"

totp = OTP::TOTP.new
totp.secret = "YVMR2G7N4OAXGKFC"
p totp.verify("123456")  #=> true/false (verify given passowrd)

The value of "secret" is encoded with BASE32 algorithm to be compatible with Google Authenticator URI format.