What is a Personal E-mail Certificate?

Personal E-mail Certificates are designed to show that an email has not been modified or tampered with after it has been sent. They are added as the email message leaves your mail client, before passing through the Secure SMTP server. Any changes made to your message after this point will invalidate the certificate. A Personal E-mail Certificate will ensure the privacy of your email by encrypting its contents and attachments and allows you to secure and guarantee authorship of your e-mail communications by digitally signing and encrypting your e-mails.

Note: You can get a free Personal Email Certificate provided by Thawte Authority.