[ Thanks to Lee
Schlesinger for this link. ]
“Many network administrators know OpenSSL as a tool that
implements Secure Sockets Layer (SSL) and Transport Layer Security
(TLS) cryptographic protocols to secure your web surfing and email.
But as we learned earlier this month, OpenSSL can do far more. With
OpenSSL you can encrypt and decrypt files, verify file integrity,
and see which encryption protocols and ciphers any server
supports.“If you want to keep your files from unauthorized access, Linux
file encryption tools like GnuPG, EncFS, and TrueCrypt are
excellent and easy to learn, but you don’t need another application
to encrypt files if you already have OpenSSL. For instance, the
command below encrypts a single file, in this example file-test.
You can name your output file anything you want, or you can omit
the output file spec if you want to print the file to your screen.
OpenSSL prompts you twice for a password that you’ll need to
specify when you decrypt the file:”