Hello John, JW> Yes...you're right. Bytecode is essentially reversible. However, note I JW> mentioned obfuscated bytecode. Obfuscation can make reverse engineering JW> impractical, if not impossible. I'm looking for the equivalent in Ruby. Don't use the exe converters that other persons mentioned. In a previous discussion about this i posted a generic 5 lines crack patch for all of them. Use google to search the comp.lang.ruby group for this patch and the discussion. You must extend the ruby interpreter and change the internals of some function names to do it. This will work, then use one of the commerical copy protection systems like armadillo to protect the source code from decryption. -- Best regards, emailto: scholz at scriptolutions dot com Lothar Scholz http://www.ruby-ide.com CTO Scriptolutions Ruby, PHP, Python IDE 's