[Y_Less]

A better question is why are you encoding things in the first place - this is a very important question! If you need encoding for things like passwords then you're going about it very wrong - passwords should not be decodable. You test people entered the right password by encoding what they typed and checking that encoded string against the stored encoded string. Also, if this is for passwords, you are using the most basic form of encryption ever - straight replacement. There is a plugin for whirlpool which is a much better encoding method, AFAIK it's not been cracked yet.

If you are encoding data other than passwords for storage then I would still recommend a different algorithm. DSA is quite fast for large stream data and can be decrypted if you have the key.