Wednesday, July 1, 2009

New Attack on AES, is Pointsec broken?

Like many people in the security world, I keep a close eye on Bruce Schneier's blog. Today I was a little scared when I read about a new attack on AES that has theoretically broken the cipher. You can read Schneier's comments on it here:

The reason that this freaked me out at first is because the default encryption algorithm used by Check Point Full Disk Encryption (formerly known as Pointsec). Much of my personal data is protected by Check Point FDE and I don't want to see it exposed. The good news is that while this may fit the dictionary definition of a break, it is far from the end of the world.

The freakout comes from the difference between what a cryptologist calls a broken algorithm and what broken algorithm means to a typicaly person on the street. When you tell me that AES is broken, I think that it has been made completely worthless (or nearly worthless as is the case with DES). However, cryptologists have a much different definition. For them, a break means that someone found a way to get at the plaintext data in a more efficient way than simply trying all of the possible code combinations that exist. In this case, they found a way to reduce the number of possible code combinations from 2 to 119th power down to 2 to the 110th power.

So basically, AES is still very much alive and kicking. It is very unlikely that anyone is going to be able to exhaustively search through 2 to the 110th power code combinations and still derive value from your data. This is one of the points that I try to stress in my Full Disk Encryption classes, though. No encryption algorithm is perfect and able to remain eternally unbreakable. The power of encryption is to deny access to information for such a long period of time that the information is no longer valuable. For example it is worthless for the enemy to learn about tomorrows battle plan 35 years from now. The flip side of that coin is that if someone could theoretically gather enough computing resources to break your encryption in a short amount of time (say one week for example) the cost would exceed the value of the information. In other words, I would not spend tens of billions of dollars to break your encryption so that I could get your credit card number that has a limit of $5,000.

So if Check Point Full Disk Encryption broken? Well, maybe in a theoretical sense, but absolutely not in a practical sense.

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