For using SSL, does the client side need to have a digital certificate (X.509v3)? If so, then why can I access secure Web sites from my computer that seemingly does not have a certificate? If it is not needed, then how does the client send its public key across to the secure server?
Requires Free Membership to View
SearchSecurity.com members gain immediate and unlimited access to breaking industry news, virus alerts, new hacker threats, highly focused security newsletters, and more -- all at no cost. Join me on SearchSecurity.com today!
Michael S. Mimoso, Editorial DirectorNo, you do not need a certificate to use SSL. If you have one, it can be used to authenticate you to the server, but if you don't, then some other mechanism (like a password) can be used.
When you set up an SSL connection, usually, a Diffie-Hellman key exchange is done, but each side can actually negotiate how it is done.
You can find all the rules for how this is done in RFC 2246, the IETF standardization of SSL called Transport Layer Security. You can find this at http://www.ietf.org/rfc/rfc2246.txt.
For more information on this topic, visit these other SearchSecurity.com resources:
Ask the Expert: Finding the answers to specific SSL questions
News & Analysis: OpenSSL expert details flaws
This was first published in September 2002