A PGP keypair consists of a private key and a public key. A public key is used to encrypt files or email messages and the private key is then used to decrypt any files or email messages.
This article explains how to back up your PGP keys. Backing up your private key file is very important because once you have encrypted data to your public key; only the corresponding private key can be used to decrypt the data.
To back up your private key
Note: Copy the file to a secure location. This may be a CD which you carefully archive, another personal computer, or a USB flash drive that you keep in a safe location. Remember not to distribute this file to others, as it contains both your private key and your public key.