Android Google Play In-App purchases verification in Ruby

google_play_purchase_verification.rb

module Android
  def self.verify_purchase(receipt_data, signature)
    android_inapp_public_key = Rails.application.secrets[:android_inapp_public_key]
    public_key = OpenSSL::PKey::RSA.new(Base64.decode64(android_inapp_public_key))
    unless public_key.verify(OpenSSL::Digest::SHA1.new, Base64.decode64(signature), receipt_data)
      raise "Wrong Android payment"
    end
  end
end