MessageVerifier makes it easy to generate and verify messages which are signed to prevent tampering.

This is useful for cases like remember-me tokens and auto-unsubscribe links where the session store isn't suitable or available.

Remember Me:

cookies[:remember_me] = @verifier.generate([@user.id, 2.weeks.from_now])

In the authentication filter:

id, time = @verifier.verify(cookies[:remember_me])
if time < Time.now
  self.current_user = User.find(id)
end

By default it uses Marshal to serialize the message. If you want to use another serialization method, you can set the serializer in the options hash upon initialization:

@verifier = ActiveSupport::MessageVerifier.new('s3Krit', serializer: YAML)