This paper reveals the aspects of .NET runtime encryption and presents a proof of concept implementation for Hyperion, the implementation that generates a random key and uses it to encrypt the input file with AES-128.
You can download it from the following link: https://packetstormsecurity.com/files/download/118837/nullsec-net-crypter.pdf
Source: https://packetstormsecurity.com/files/118837/Ideas-On-Advanced-Runtime-Encryption-Of-.NET-Executables.html