OpenSSH Change a Passphrase With ssh-keygen command

Q. How do I change OpenSSH passphrase for one of my private keys under Linux?

A. Use ssh-keygen command to generates, change manages and converts authentication keys for ssh. Generally, you should the see following files at $HOME/.ssh (~/.ssh directory i.e. /home/you/.ssh/)

=> id_dsa : DSA authentication identity of the user

=> id_dsa.pub : DSA public key for authentication

=> id_rsa : RSA authentication identity of the user

=> id_rsa.pub : RSA public key for authentication

Changing a Passphrase with ssh-keygen

The -p option requests changing the passphrase of a private key file instead of creating a new private key. The program will prompt for the file containing the private key, for the old passphrase, and twice for the new passphrase. Use -f {filename} option to specifies the filename of the key file. For example, change directory to .ssh:
$ cd .ssh
To change RSA passphrase, enter:
$ ssh-keygen -f id_rsa -p
To change DSA passphrase, enter:
$ ssh-keygen -f id_dsa -p