Download encryption examples generated by Poly Polymorphic Engine.
In the example below you can find a modified version of the system utility Notepad, where part of its executable code was encrypted with Poly Polymorphic Engine.
Upon launch, control is transferred to the generated decryption routine, which decrypts the original application code and transfers control back to the OEP (Original Entry Point), from which point the original application runs just as it normally would.
The ZIP file contains exactly the same application (Notepad) encrypted 3 times, so you can check for yourself that the polymorphic code generated by the Poly engine is completely different each time.
I encourage you to analyze the polymorphic decryption routine yourself. If you don't know how, but you would like to learn — read my reverse engineering analysis articles.
You may receive warnings from anti-virus software, because files from the archive can trigger false positives due to the simplistic nature of the code modifications in the executable.
If you would like to ask me about Poly Polymorphic Engine, or something's not clear, mail me. I'll be happy to answer all of your questions.