A novel method for out-of-band key verification that improves on both the usability and the security of the numeric-code method is provided. The method use portions of the generated keys as inputs to perform procedural image generation to produce a visualization at each of the two devices that the user can visually compare and confirm. This visualization can be a static image or a motion animation. The method can uses more of the key data to generate visualizations with more features to reduce the likelihood of false matches. The method can also use less key data to allow for quicker comparison and confirmation.