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E-mail
electronic mail
Whenever you send messages to people using a computer and they read it later, you've sent a piece of email. You can send email in several ways across a local area network, via the Internet, or through an online service like CompuServe or America Online and you can send it to a single recipient or to a whole slew of them. But all email behaves pretty much the same way: you send it to a virtual mailbox, and the recipient has to pick it up or can use software that does it automatically.
Encryption
Encryption is the process of changing data into a form that can be read only by the intended receiver. To decipher the message, the receiver of the encrypted data must have the proper decryption key. In traditional encryption schemes, the sender and the receiver use the same key to encrypt and decrypt data. Public-key encryption schemes use two keys: a public key, which anyone may use, and a corresponding private key, which is possessed only by the person who created it. With this method, anyone may send a message encrypted with the owners public key, but only the owner has the private key necessary to decrypt it. PGP (Pretty Good Privacy) and DES (data encryption standard) are two of the most popular p