Attacking WinZip AES Encryption

bden writes "As another tidbit from Bruce Schneier's Crypto-Gram, remember back in January when WinZip was Slashdotted for moving forward with its new AES-based encryption technology? Everything sounded good since we all knew that AES is secure, right? Well, a cryptographer took a look at how WinZip uses AES and found lots of problems. Regardless of how many people actually plan to use WinZip encryption, the lesson, according to Schneier, is that "cryptography is hard, and simply using AES in a product does not magically make it secure." So how can we distinguish between an application that simply uses the right buzzwords, like AES, from an application that is actually secure?"

Comments

Simple

[Anonymous Coward]

So how can we distinguish between an application that simply uses the right buzzwords, like AES, from an application that is actually secure?"

By only using peer reviewed open source software for starters.

FP?

Re:Simple

[enditallnow]

Its questionable whether this would help commercial applications. Not every company offering secure programs wants their source code floating about the internet (Insert Microsoft Joke Here).

I agree that the best way to ensure that an application is secure is for it to be reviewed by someone who knows their shit. Quite simply its the only way to be sure at this point in time. Perhaps an authoritive body should be formed comprising of cryptographers that grants their seal of approval on it. Then again, doesn't the US government have to give its authorisation for cryptographic software to be exported? I recall that DES had to go through such motions, and if i'm not mistaken PGP can't be shipped outside of the US because its considered military grade cryptography? If im wrong please correct me, its been a while since I read over this topic and my memory is a bit hazy.

BTW, open source does not necessarily imply increased security. I'd rather have the word that a piece of software is secure from a professional like Bruce Schneier rather than an Open Source zealot who skimmed over a copy "Applied Cryptography" in their local Borders.

-- Enditallnow

Predictable..

[Ckwop]

I think the problem is people approach to the security.
They think you can just take AES and HMAC and glue them together in any way
and arrive at security. I mean both are secure right? The result should be secure?

Wrong! Schneier names one of the chapters in one ofhis book: "Cryptography is hard but that's just the easy part!"

It really is very hard to secure information. It's almost intractable.. We've seen a few articles here in the last week about interesting side-channel attacks. Breaking RSA keys by listening and an earlier one which broke into computers by heating them up.

Cryptography is littered with broken designs fielded designs like WEP and let's not mention software security..

It's going to be twenty years before we have "trustworth computing". It would help if we could modularize cryptography like we can computer programs...

Simon.

Re:is this a testament to today's computing power?

[TedCheshireAcad]

I took a class in cryptography last semester. The professor offered the best words of advice I ever heard in the subject: "Don't try to create new algorithms. We know how to do that already. What we have is secure. What you need to work on is the implementation. Just because something uses encryption, it is by no means secure."

He then proceeded to explain how easily NTLM can be defeated in a brute force attack.

not everything in the paper a Winzip vulnerability

[Anonymous Coward]

While most of the points raised in the paper seem valid, some done make sense. Case in point: "someone may use a keystroke logger to find out what your passphrase is". How the fuck is this a Winzip vulnerability?