On May 9, 2009, at 8:40 AM, Ross Lawley wrote:
Its not *just* noise, its not the first time such conversations have come up and I'm yet to be convinced javascript can provide a solid solution.
No one ever said it was fool-proof, its an alternative to using SSL. I've never heard anyone propose that optionally allowing a more secure (than just plaintext) login scheme actually makes things less secure. Can you elaborate on how automatically using a slightly more secure scheme (when available) actually makes things less secure?
At the end of the day you’re not sending information over a trusted channel, that is the issue.
Lots of secure systems use challenge-response to securely send information over a non-trusted channel, like say, public-private key crypto systems. Are they all insecure?
If you don't want to pay the cost of https, then use someone elses; OAuth, OpenID.
OAuth is not for logins, its for something else entirely (client-side programs that need access to data, and last I checked it actually uses challenge-response like Paul's scheme). OpenID requires a user to have an OpenID provider, this system is merely an alternative to a plain- text login for a site. OpenID add's a hell of a lot more complexity to the server-code than this scheme (way way way way more, it sucks to implement), with plenty of new attack vectors. I'm baffled that you'd consider it a better option.
Does client side encryption hurt anything here? No. But is there a serious threat model that it helps with? No.
It helps prevent those who can watch the line between you and the server, because they no longer get to see passwords fly over in clear text all day long. Does that help? You betcha. Is it as secure as SSL? Nope, this is just an optionally more secure scheme than plain-text for clients that support it (which most do).
Paul, on a side-note, I'd be interested in making some helpers that allow one to easily setup your system. WebHelpers already has a helper in it now that can be used with a Pylons decorator, that drops in a unique token into a form to prevent CSRF attacks. I can see a similar Pylons decorator, with a WebHelper generator that would make it easy to drop in optional use of your system for anyone making a login form.
Cheers, Ben
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