these are my suggestions:
1. make /share with us your class design in UML (or similar) diagrams
2. separate your class in two:
a) encrypt class (maybe abstract class, or "bridge" or "wrapper") 
b) hide class (maybe abstract class, "bridge" or "wrapper")
Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides
Design Patterns - elements for reusable object-oriented software.
Chao-Chyuan Shih - 2005-04-08 14:11:38 - In reply to message 3 from fru
Sounds good. Please do send me your UML diagrams. As a matter of fact, I am pretty new to the PHP program myself, less than 7 months so far. But I have beeing programming in C/C++ for over 15 years. CAD programming used to be the only thing I did in the past 15 years. Just recently I quit my job and start up my own business. Still not quite sure what I should do :)
Anyway, let's work on this TxtCrypt project and make it useful!!!