"MD5 considered harmful today"... but why?

  algorithms certificates collisions digital_signature_forgery digital_signatures hashes massively_parallel_computation md5 message_digests pki public_key_cryptography ssl

If you've been following net.news in the past twenty-four to forty-eight hours you heard about what went down at the Chaos Computer Congress yesterday - a group of security researchers figured out how to exploit the flaws in the MD5 hash algorithm to forge CA certificates, thus placing SSL encryption as we know it in jeopardy.

...right? Breaking SSL is bad, yeah?

Like many things in life (and nearly everything in cryptography) it's not that simple or that straightforward. Yes, this is bad, but it's not "go back to punchcards" bad.

Let's take it step by step. First of all …