The Encryption plugin provides you with Blueprints to encrypt bytes, so they can safely be stored or send across the network.
The most important feature of this plugin is that this plugin has also been designed to be used in conjunction with a server programmed in Java, like an account server or a match making server for example.
To make this possible, the encryption algorithms have also been programmed in a Java library, which has been made free and open source.
The Java library is available here.
PS: you can convert bytes to and from string (and more) with the LE Extended Standard Library plugin (which is free)