Your e-mail may contain sensitive or confidential information that you need to protect from unauthorized disclosure by someone who manages to intercept your messages. Encrypting your e-mail ensures that only you and the intended recipients are able to read it.
E-mail encryption makes use of digital IDs, which are essentially certificates used in Public Key encryption. Public Key encryption uses a pair of certificates—a private key certificate and a public key certificate. The private key enables you to create a public key that you can share with others so that they can read the e-mail you encrypt. Others can use your public key to encrypt e-mail to you that you can decrypt and read using your private key.
Encryption is a powerful tool, but with all those unfamiliar acronyms, it can also be intimidating. If you are using a digital ID, however, you will find that the default settings work just fine in almost every circumstance. This means you can simply obtain and install a certificate to start sending encrypted e-mail, without worrying about too many details.