Encryption and cryptographic software has been used in many different ways to make systems more secure. There are many more programs out there that will help, they have the added benefit of both being free with source code available.
Encryption simply makes it harder for people to gain access to important information, like passwords or sensitive information in a file. The first thing you should know about encryption is that the algorithm that is used to encrypt can be simple or more complex and that affects how securely what you have encrypted is protected. Encryption systems have been broken when the method of encryption is understood by hackers and is easy to break.