How to encrypt/decrypt a file in Java?

Question

I am writing a Java application which can \"encrypt\" and consequently \"decrypt\" whatever binary file.

I am just a beginner in the \"cryptography\" area so I would

Answer 1

Don't store it there! Any good encryption is based on mathematical algorithms (like AES). You may want to have a look at BouncyCastle http://www.bouncycastle.org/ - but encryption is not a simple topic, so you should get a good book to learn about its basics first!