>Thanks to Anatoliy and Alex for the responses.
>Where can I get more information on the terms that are used about PGP encryption. Terms like public keyring, private keyring, keyid, passphrase...
>I am new in this area. We are supposed to encrypt a text input file with a public key provided by the recipient and the file will be decrypted with a private key by the recipient. How does the public key and the private key work together safely ?

Kam:

You have to understand the basics of cryptographic systems.
You have a private-public key pair. You keep your private key and you get the public key from your associate (by a secure-trusted means so you are sure the key belongs to your other party).

You then encrypt using your private key and his public key. The other party must use your public key plus his private key. Anything else fails. This is also called Asymmetric Cryptographic.

Contrast this to Symmetric or Private Key cryptography where the same password is used to both encrypt and decrypt, so you have to send the encrypted file and the password to decrypt it must be known to both parties.

Key rings are the files used by PGP to keep your private and public keys from other people you corrspond with.

Here are some good basic references.
http://en.wikipedia.org/wiki/Public-key_cryptography
http://world.std.com/~franl/crypto.html

HTH