Jeff Atwood

2,273 reputation

41424

bio	website	codinghorror.com/blog
	location	El Cerrito, CA
	age	42
visits	member for	2 years, 6 months
	seen	Apr 1 at 18:13
stats	profile views	647

Stack Overflow Valued Associate #00001

Wondering how our software development process works? Take a look!

Find me on twitter, or read my blog. Don't say I didn't warn you because I totally did.

However, I no longer work at Stack Exchange, Inc. I'll miss you all. Well, some of you, anyway. :)

	2,273 reputation	bio	website	codinghorror.com/blog	visits	member for	2 years, 6 months
41424 badges		location	El Cerrito, CA		seen	Apr 1 at 18:13

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Mar 20	comment	XKCD #936: Short complex password, or long dictionary passphrase? @gilles well, I do agree that length is an issue in a realm of hardware cracking, see my blog post codinghorror.com/blog/2012/04/speed-hashing.html -- I used my own video hardware, two high end ATI 7970s.. but people ARE implying that pass phrases can be cracked more easily as a pattern just like l33tsp34k can.
Mar 20	comment	XKCD #936: Short complex password, or long dictionary passphrase? @gilles as I said "In other words, will they actually attempt common schemes like "dictionary words separated by spaces", or "a complete sentence with punctuation", or "leet-speak numb3r substitution" as implied by xkcd?" So I will concede very basic leet-speek tables -- as Meat Loaf once said, Two out of Three Ain't Bad. But I won't concede anything else, unless you prove otherwise by cracking the above password for me! I eagerly await your results!
Mar 20	comment	XKCD #936: Short complex password, or long dictionary passphrase? @gilles well I wasn't really referring to that one, as basic letter-to-number sev7n style substitution is, admittedly, pretty mechanical if you do it totally consistently and repeatably. But passphrases are a different story. If I told you my password is "I live at 55 Maple Lane in Boston", show me the tool that will crack that in sane time using rules and not brute force. I'd love to see it, if you can. :)
Mar 15	comment	XKCD #936: Short complex password, or long dictionary passphrase? @Gilles " If there isn't any low-hanging password fruit (and oh, there always is), they'll just move on to the next potential victim service"
Jan 27	comment	Does overlaying the mouse on a virtual numeric keyboard really protect against keyloggers? hovering will not work on tablets / touch devices, which will be an increasing percentage of the computing devices in the world every year from now on.
Dec 5	comment	How do certification authorities store their private root keys? @mike someone left a long torturous comment on this post about how unfair it was to people who care about dogs. Trust me, you don't want to read it. I didn't.
Dec 4	revised	How do certification authorities store their private root keys? deleted 11 characters in body
Dec 3	awarded	Booster
Dec 3	awarded	Announcer
Nov 24	reviewed	Approve suggested edit on How valuable is secrecy of an algorithm?
Nov 16	awarded	Nice Question
Nov 15	asked	What are the supposed security benefits of a “dead-drop” email strategy?
Nov 11	awarded	Yearling
Sep 21	awarded	Custodian
Jul 30	awarded	Publicist
Jul 30	comment	How can crackers reconstruct 200k salted password hashes so fast? even with a tiny 4 character salt, assuming formspring has a reasonable minimum password length (let's say 7 characters) that puts the brute forcing at a minimum of 11 characters which is deeply into "not possible with any known computing technology" territory. I think we have to conclude that the original crackers must have the salts (as Remus pointed out in the comments to my answer, this is extremely likely), and for some reason just chose not to publish them.
Jul 30	comment	How can crackers reconstruct 200k salted password hashes so fast? it doesn't matter if the term salt means public, the salt was not published with the hashes. Compare the LinkedIn breach, where unsalted password hashes were posted. I agree that it is strange, because the crackers very likely know the salts. But not sharing them and posting just the password hashes alone means nobody can crack any of those posted password hashes; based on the math, no known computing technology is fast enough. So you have to ask "what is the purpose of publishing just the hashes of salted passwords?" Is it merely to show off and prove you did it?
Jul 30	comment	How can crackers reconstruct 200k salted password hashes so fast? true; even if you don't have real-time access to the database as the accounts are being created, I suspect most salting schemes are in the top 5 forms supported by John the Ripper, so attempting a few of those should rapidly tell you whether you are getting any "hits" on simple passwords that statistically must exist in all password sets..
Jul 30	comment	How can crackers reconstruct 200k salted password hashes so fast? summary: There is likely a difference between what the crackers posted and what they know. I agree with Remus in the comments to my answer. If the crackers have the hashes, they almost by definition have the salts. Assuming Formspring did a typical `salt + password` technique, they probably don't need access to the source code to figure out how the hashes were applied. A bit of trial and error alone could work to guess how the salts were applied. In conclusion it is very likely that the crackers know more than they posted.
Jul 30	awarded	Good Answer