Where can I find more information?

Additional resources that give more background on S/MIME, X.509 certificates, and cryptography in general.

• Understanding digital certificates and how they work — Very brief explanation of digital certificates/IDs.
• A more thorough Introduction to Public Key Cryptography — yes it's by Netscape, but it's quite clearly written.
• About Digital Certificates —  Question-Answer format explaining what digital IDs/certificates are and how they work, with emphasis on GlabalSign as the CA.
• Digital ID^SM Introduction —  A good, fairly thorough site from VeriSign explaining digital IDs and how the encryption/decryption process works.
• X.509 Certificates and Certificate Revocation Lists (CRLs) —  A slightly more detailed site from Sun on X.509 certificates; easy to understand.
• Paj's Introduction to public key encryption — Pretty good, terse diagram of symmetric and public key encryption at work.
• Working around SSL Root Certificate Errors with Entourage 2004 and Microsoft Exchange