PGP & GPG

Cryptography Kindergarten 23

new message. We need a technique to protect the hash from

tampering. Our solution is to use public-key cryptography to

digitally sign our message. Here are the basic steps the Open-

PGP software performs after you tell it to sign your message:

1. Generates a hash of your message.

2. Encrypts the hash with your private key (your digital

signature).

3. Attaches the encrypted hash to your message (this is your

signed message).

4. Sends your message with the attachment.

The recipient will get an email message containing the

message you sent in cleartext, plus a small attachment contain-

ing the encrypted hash. The recipient does not need to use

OpenPGP to read the message, so it’s less hassle to read the

message than ...