Go2Linux posted a guide about encrypting files with eCryptfs
Encrypt files, has always been needed in computer world, it could be something as simple as your diary, or as important as your private source code, for that important project.Encrypt Files
Linux offers some different approaches to provide file encryption, the most of them are focused on volume encryption, and require that you set apart some space of your disk, and dedicate it to the storage of the files encrypted. The problem with this, is that if you do not need all the space set, you will waste disk space, on the other hand if you need more room for your encrypted files, you will have to resize the volume. And that is not an easy task.