Techniques for authentication via a mobile device are provided. A mobile device is pre-registered for website authentication services. A user encounters a website displaying an embedded code as an image alongside a normal login process for that website. The image is identified by the mobile device, encrypted and signed by the mobile device and sent to a proxy. The proxy authenticates the code and associates it with the website. Credentials for the user are provided to the website to automatically authenticate the user for access to the website bypassing the normal login process associated with the website.