Looking for encryption software... suggestions?

I am looking for a very strong file encryption software 2048bit rs4 or rs5 preferred.
Has to be free ( don’t want to spend unnecessarily )
And also has to have ability to be able to make self-decryption files if given correct password so receives do not need to install.
Any suggestion?
In fact, I would very much like to see such security related tools appearing in avast.

See, if this meets your needs…
http://www.gnupg.org/
asyn

I will give it a try, thank you.

You’re welcome…!