I recently produced an open source implementation of Steve Gibson's Perfect Paper Passwords system in C. It occurred to me that a better implementation would be a Java client for my mobile phone (thus eliminating the need for printing and carrying the paper passwords). Here's my PPP client implementation running on my Motorola RAZR. It's written in Java using CLDC 1.0 and MIDP 2.0 . You can download and install the JAR file . The current version is 1.0.0.