A Photo Certificate-A Framework for Generating Visualized Public Key Certificates

In the proposed photo certificate, the principal component is the image, for example, the user’s photo. User-related fields, such as the subject’s name, the issuer’s name, and the expiration period, which are meaningful to users, are embedded into the surface of the photo by using a visible watermark algorithm, so that the reader can capture this information without the requirement for special software. The remaining fields in the certificate are embedded into a marked photo. Later, the whole photo certificate is cryptographically signed by certification authority (CA) private key to guarantee the integrity of our photo certificate. By such arrangement, the certificate’s verification is divided into two layers. The first layer is human visual system oriented and the second layer is the software-oriented. User can determine whether the user’s photo and its subject’s name are consistent and check whether the expired period is valid first. The second layer’s verification is lunched only when the first layer’s verification is passed. To sum up, the proposed photo certificate not only inherits the functions of a traditional certificate, but also provides a friendlier operational environment of X.509 certificate.