Vijner 974 E-Sys (2048 bits and unlimited encryption). Enables easy (un-)encryption from text input or .txt file, and to (un-)encrypt raw files, with Vigenère Algorithm + unlimited encryption keys. Simple and powerful. Adapt to fit your needs.
RC4.NET is a library that adds support for encrypting/decrypting using the symmetric RC4 algorithm in the .NET environment. The library is written in C# language, and performs equally well on both the Microsoft CLR and Mono platform.