What is the difference between signing and encrypting an e-mail?

Signing an e-mail message means that you attach your Digital Certificate to it so that the recipient knows it came from you and was not tampered with en-route to their inbox. Signing authenticates a message, but it does not provide protection against third party monitoring.Encrypting a message means scrambling it in such a way that only the designated recipients can unscramble it. This safeguards messages against monitoring or interception. In order to send a signed message, you must have a Digital Certificate. Since message encryption is done using specific keys available in the certificate, you cannot encrypt a message unless you possess the recipient’s Digital Certificate.