Test TOTP collision

totp_collision.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rotp"
  gem 'activesupport'
end

class Otpable

  DRIFT = 20# 10 days

  attr_accessor(:totp, :proof)

  def initialize
    @totp = ROTP::TOTP.new(ROTP::Base32.random, issuer: 'Club service')
  end

  def generate_otp
    @proof = totp.now
  end

  def verify_otp(drift_behind: DRIFT)
    totp.verify(proof, drift_behind: drift_behind)
  end
end

require 'active_support/testing/time_helpers'

include ActiveSupport::Testing::TimeHelpers

100000000.times do |i|
  optable = Otpable.new

  optable.generate_otp

  print "."
  raise "SHOULD NOT BE NIL" if optable.verify_otp.nil?
  travel_to(Time.now + (Otpable::DRIFT * 2)) do
    raise "SHOULD BE NIL" unless optable.verify_otp.nil?
  end

rescue => e
  puts
  puts "Failed at #{i} times"
  puts
  raise e
end