Re:Adding Easy SSL Client Authentication To Any Webapp
by scriptjunkie on Saturday November 30, 2013 @09:19PM
(#6825751)
Private keys should have over 128 bits of entropy, which is enough to make it un-brute-forceable with at least the amount of energy likely to be obtained by any human organization on earth. http://en.wikipedia.org/wiki/Brute-force_attack#Theoretical_... That's what makes it un-guessable. Also, some users do choose passwords with at least as much entropy and are also unguessable. But most don't.
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Re:Adding Easy SSL Client Authentication To Any Webapp
by mnordhoff on Saturday November 30, 2013 @11:57PM
(#6826183)
Security FYI:
This situation concerns RSA keys, not 128-bit symmetric keys; our problem is "factoring a really big number", not "guessing a really big number". A 128-bit RSA key can be broken in seconds.
RSA keys are commonly 2048 bits at the moment. NIST's rough rule of thumb is that a 2048-bit RSA key is equivalent in secureness to a 112-bit symmetric key; for 128-bit equivalence, you need around a 3072-bit RSA key. (2048 provides fine security for the next few decades at least.)
Edit:
You referred to "128 bits of entropy", which could be interpreted as "equivalent to a 3072-bit RSA key". I'm not accusing you of recommending insecure RSA key sizes, I just wanted to make a public service announcement. I've seen people make that mistake before.
Re:Adding Easy SSL Client Authentication To Any Webapp
by dmix on Saturday November 30, 2013 @11:11PM
(#6826058)
I use automated high-entropy password-generators and a surprising amount of websites cap lengths to 30-50 characters (or even 8 chars sometimes like a Canadian bank I won't name). Allowing super-long passwords would be a good starting alternative to SSL.