A network device and method are directed towards providing a client side sign-in seal for use detecting phishing attempts. In one embodiment, a user of a client device may provide anti-phishing data through a sign-in setup user interface for a website, application, or the like. In one embodiment, the anti-phishing data is an image provided by the user. The user may also provide text, symbols, an audio clip, or the like. The user may also modify aspects of the image, text, symbols, or the like, such as a color. When the user accesses the website, application, or the like, the client device may provide client device data used to locate and display the sign-in seal. If the user is being phished, the anti-phishing data may not be displayed or otherwise played.