Some easy choices for encrypting files on Linux
There are numerous commands for encrypting files on Linux. When you want to limit access to file contents, you can use file permissions but file encryption makes limiting access much more effective. This post compares some of the commands for encrypting files and provides an easy script for trying them out.
Encryption means, of course, that a file that you can look at with Linux commands and tools is altered in ways that make it unusable and unreadable unless you reverse the encryption process. Encryption does not generally reduce the size of files unless compression is used as well. In fact, the encryption process might make some files larger. Some commands compress by default; others do not.
Source:: Network World – Linux