totp_qr_code_generation.rb

require 'digest/md5'
require 'base32'
require 'rqrcode'
require 'rotp'

def print_as_qr(string)
  qrcode = RQRCode::QRCode.new(string)
  filename = File.expand_path "~/Desktop/qr_#{rand(10_000)}.png"
  qrcode.as_png.save(filename, :fast_rgb)
end

def create_qr(totp, email)
  uri = totp.provisioning_uri(email)
  print_as_qr(uri)
end

email = "example@test.com"
# secret = ROTP::Base32.random_base32 
secret = Base32.encode(Digest::MD5.hexdigest(email + "salt")).slice(0,16)
totp = ROTP::TOTP.new(secret, issuer: "AppName")

create_qr(totp, email)