Crypticqr is a project mainly written in RUBY and JAVASCRIPT, it's free.
Cryptic QR - Secure QR codes
== Cryptic QR
Cryptic QR is a web application that allows the generation and decoding of encrypted QR codes. This is a prototype designed for teachers to use when creating graded activities that are individualized or randomyl generated for each student.
A working sample is running at http://crypticqr.herokuapp.com
More information to follow shortly.