Usability of Augmented Reality for Revealing Secret Messages to Users but Not Their Devices

We evaluate the possibility of a human receiving a secret message while trusting no device with the contents of that message, by using visual cryptography (VC) implemented with augmented-reality displays (ARDs). In a pilot user study using Google Glass and an improved study using the Epson Moverio, users were successfully able to decode VC messages using ARDs. In particular, 26 out of 30 participants in the Epson Moverio study decoded numbers and letters with 100% accuracy. Our studies also tested assumptions made in previous VC research about users' abilities to detect active modication of a ciphertext. While a majority of the participants could identify that the images were modified, fewer participants could detect all of the modifications in the ciphertext or the decoded plaintext.