OpenSSL

What is a passphrase and how can i change the passphrase on my private key file?
A passphrase is a word or phrase that protects private key files. It prevents unauthorized users from encrypting them. Usually it's just the secret encryption/decryption key used for Ciphers.

To change the passphrase you simply have to read it with the old pass-phrase and write it again, specifying the new pass-phrase.

You can accomplish this with the following commands:

openssl rsa -des3 -in myserver.key -out server.key.new mv server.key.new myserver.key

The first time you're asked for a PEM pass-phrase, you should enter the old pass-phrase. After that, you'll be asked again to enter a pass-phrase - this time, use the new pass-phrase. If you are asked to verify the pass-phrase, you'll need to enter the new pass-phrase a second time.