rijndael256

This project it's a adapted version: https://github.com/agl/pond/blob/master/panda/rijndael/rijndael.go

The original file was changed to implement the Go standard Chipher Block interface: https://golang.org/pkg/crypto/cipher/#Block

You can use Rijndael256 for 256 bits key size.

Feel free to make improvements! :D