Slashdot Mirror
Crypto Snake Oil
An anonymous reader writes "Luther Martin of Voltage Security has published an article about the perception of cryptography today with regards to quality and honesty in vendors. From the article: 'Products that implement cryptography are probably credence goods. It requires expensive and uncommon skills to verify that data is really being protected by the use of cryptography, and most people cannot easily distinguish between very weak and very strong cryptography. Even after you use cryptography, you are never quite sure that it is protecting you like it is supposed to do.'"
I'm not so sure. Once a flawed implementation has been broken, there will be tools to crack it.
Take WEP for example. I personally wouldn't know how to crack it. But others do. They develop tools. Et voila, today it's trivial to download some tool and break WEP, even for novices.
Weak encryption is never good and should be strongly discouraged.
Of course it runs NetBSD. BTC: 1NT7QvbetmANwaMzhpVL6
I'm not so sure. Once a flawed implementation has been broken, there will be tools to crack it.
Plus, if there is *no* encryption, people are less likely to put sensitive information in the application.
To use an analogy, consider two locker rooms. Room A does not have locks on any of the lockers. Room B has locks, but all of them have the same combination. In which one is a person more likely to leave their wallet?
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I would say that there is an inverse relation (at least somewhat) between price of crypto software and real security.
:-)
The cheaper the software is, the greater the number of people who could have peer-reviewed it for correctness. The more open the software, likewise.
Really expensive software could only have been peer-reviewed by a small number of people, while free, open source software could have been reviewed by a huge number of people.
I recently was asked to recommend a way for my CEO and several other executives to securie thier IMs. I recommended gaim + gaim-encryption because it was all open source and free, so if there were a flaw in the crypto implementation, it would likely have been discovered already.
I also made sure the CEO knew that he was using open source software, and I told him why. He was totally down with it
A slashdotter who didn't build his own computer is like a Jedi who didn't build his own lightsaber.
or you could just take the common sense approach and use products that rely on algorithms that are open, widely tested and reviewed, and known secure. Algorithms like Blowfish, AES, etc. I use Apple's built-in Filevault protection to encrypt my Powerbook's hard disk, in the event that it is ever stolen. It uses AES-128, which means I know that no-one is getting in without my password.
Any vendor that relies on a custom algorithm for their encryption technology shouldn't be trusted.
It's pretty well known that there are many snake oil products that deploy cryptography. Bruce Sneier frequently displays snake-oil cryptography products in his newsletter, for instance. And these are just the really obvious ones.
Some time ago, I tried to evaluate if a Enterprise Service Bus (intercomponent communication) was fit enough to be put into a production environment. It said that it had AES encryption build in. When I looked at the manual, it displayed a pop up window where you could choose the key-size. It listed exactly all key sizes that were *not* possible for AES. This was a very short evaluation, I can tell you. This also shows a very important thing about cryptography: the algorithms used say very little about the security of an application.
Generally, the manual for cryptographic services is easy to find. This is simply because cryptography is added at the end of the development lifecycle. This is logical because cryptography is not part of the main functionality of most applications (e.g. mime encryption in email products). It's something that was added after the products main functionality was finished. So just look at the last paragraph, or Appendix Z and you are looking at it.
Sometimes it is easy to see why so many products contain bad cryptography. Take XML signatures for instance. XML signatures themselves contain *references* to the data that is signed and the cryptographic techniques used. If you are to verify an XML digital signature, you *must* check if these are not altered. Furthermore, you must keep the XML schema-definitions on your own disk, and not retrieve them from the internet. Nevertheless, I've not seen any API-documentation even mentioning this rather obvious cryptographic insight. You can rest assured that there will be many implementations that will get this wrong.
Cryptography is hard.
The real insight of this story is the listing of the products into "credence goods". If you can call this new insight. Otherwise, it's just stating the well known/obvious.
sci.crypt is a good read if you are interested in Crypto. However it does tend to get a bit antagonistic towards newbies - and it's not hard to see why.
Approximatly every 12.5 minutes someone turns up claiming to have invented a new:
Random number generator
Unbreakable encryption method
Implimentation of old methods that makes them unbreakable
Proof that shows that all crypto is worthless
The percentage of loons is *so* high that anyone who does have an interesting idea (and who doesn't publish in reputable journals) is dismissed out of hand.
For example, here is a typical conversation from the one sane new poster (posted somewhere between the 999,999 people trying to sell "200000 bit quantum crypto based on the randomness of STARS!!!!!"):
<i>** Hi, I'd like to find out if there's a RNG sandbox somewhere so I can play about with some ideas.</i>
<i>* ARGH! Dont impliment your own RNG! It'll be crap! Here, use product X.</i>
Well, yes, that's true. When it comes to crypto there is a 99% chance that what you impliment will not work properly and as a result will be insecure... but stoping on someone who wants to try some ideas out is just plain wrong. All research doesnt have to take place in academic institutions.
Beep beep.
This is something I've often considered about commercial encryption software. There's just no way to be sure of their validity, as they are closed source implementations. Open source solutions like Truecrypthttp://truecrypt.sourceforge.net/ are at least somewhat more trustworthy, in that they can be openly reviewed by anyone. Despite the fact that I know jack all about the specific math behind AES and such, at least I can read some simple explanations of the concepts, read the source, and decide if I want to trust my data to it. Honestly, unless we get down to the fraction of the population that actually does understand these bits at a deep level, that's the best any of us can do really.
Sure, large clusters of powerful servers working in tandem(or quantum computing) may render the factoral math behind crypto obsolete. A nice thing though, is that those kind of solutions are limited to those that can afford them. Still, even if it's all true, and I'm wasting my time encrypting things, what better solutions do we have?