Essays: 1999 Archives
The 1999 Crypto Year-in-Review
In 1999, the major developments in cryptography were more political than scientific. Of course, there were scientific conferences and scientific announcements, some of which were significant. But, by far, the most important events happened in the areas of law, court cases and regulation. As we move into the new millennium, these political and regulatory shifts could have resounding effects on the implementation of cryptography, especially in how it relates to balancing privacy concerns with the needs of government and law enforcement.
U.S. Export Control…
A Plea for Simplicity
You can't secure what you don't understand.
Ask any 21 experts to predict the future, and they’re likely to point in 21 different directions. But whatever the future holds—IP everywhere, smart cards everywhere, video everywhere, Internet commerce everywhere, wireless everywhere, agents everywhere, AI everywhere, everything everywhere—the one thing you can be sure of is that it will be complex. For consumers, this is great. For security professionals, this is terrifying. The worst enemy of security is complexity. This has been true since the beginning of computers, and it’s likely to be true for the foreseeable future…
DVD Encryption Broken
A version of this article appeared as a guest commentary on ZDNet.
The scheme to protect DVDs has been broken. There are now freeware programs on the net that remove the copy protection on DVDs, allowing them to be played, edited, and copied without restriction.
This should be no surprise to anyone, least of all to the entertainment industry.
The protection scheme is seriously flawed in several ways. Each DVD is encrypted with something called Content Scrambling System (CCS). It has a 40-bit key. (I have no idea why. The NSA and the FBI shouldn’t care about DVD encryption. There aren’t any encrypted terrorist movies they need to watch.) It’s not even a very good algorithm. But even if the encryption were triple-DES, this scheme would be flawed…
Why Computers Are Insecure
A shortened version of this essay appeared in the November 15, 1999 issue of Computerworld as “Satan’s Computer: Why Security Products Fail Us.”
Almost every week the computer press covers another security flaw: a virus that exploits Microsoft Office, a vulnerability in Windows or UNIX, a Java problem, a security hole in a major Web site, an attack against a popular firewall. Why can’t vendors get this right, we wonder? When will it get better?
I don’t believe it ever will. Here’s why:
Security engineering is different from any other type of engineering. Most products, such as word processors or cellular phones, are useful for what they do. Security products, or security features within products, are useful precisely because of what they don’t allow to be done. Most engineering involves making things work. Think of the original definition of a hacker: someone who figured things out and made something cool happen. Security engineering involves making things not happen. It involves figuring out how things fail, and then preventing those failures…
Risks of Relying on Cryptography
Cryptography is often treated as if it were magic security dust: “sprinkle some on your system, and it is secure; then, you’re secure as long as the key length is large enough—112 bits, 128 bits, 256 bits” (I’ve even seen companies boast of 16,000 bits.) “Sure, there are always new developments in cryptanalysis, but we’ve never seen an operationally useful cryptanalytic attack against a standard algorithm. Even the analyses of DES aren’t any better than brute force in most operational situations. As long as you use a conservative published algorithm, you’re secure.”…
The Trojan Horse Race
1999 is a pivotal year for malicious software ( malware) such as viruses, worms, and Trojan horses. Although the problem is not new, Internet growth and weak system security have evidently increased the risks.
Viruses and worms survive by moving from computer to computer. Prior to the Internet, computers (and viruses!) communicated relatively slowly, mostly through floppy disks and bulletin boards. Antivirus programs were initially fairly effective at blocking known types of malware entering personal computers, especially when there were only a handful of viruses. But now there are over 10,000 virus types; with e-mail and Internet connectivity, the opportunities and speed of propagation have increased dramatically…
One of the stranger justifications of U.S. export controls is that they prevent the spread of cryptographic expertise. Years ago, the Administration argued that there were no cryptographic products available outside the U.S. When several studies proved that there were hundreds of products designed, built, and marketed outside the U.S., the Administration changed its story. These products were all no good, they argued. Export controls prevent superior American products from getting into foreign hands, forcing them to use inferior non-U.S. products…
Web-Based Encrypted E-Mail
A version of this essay appeared on ZDNet.com.
The idea is enticing. Just as you can log onto Hotmail with your browser to send and receive e-mail, there are Web sites you can log on to to send and receive encrypted e-mail. HushMail, ZipLip, YNN-mail, ZixMail. No software to download and install…it just works.
But how well?
HushMail <http://www.hushmail.com> is basically a PGP or S/MIME-like e-mail application that uses Java (although oddly enough, HushMail is not compatible with either). The sender logs onto the HushMail Web site, and encrypts messages using a Java applet that is automatically downloaded onto his machine. Both the sender and receiver need to have HushMail accounts for this to work. Accounts can be anonymous…
NIST AES News
A version of this essay appeared on ZDNet.com.
AES is the Advanced Encryption Standard, the encryption algorithm that will eventually replace DES. In 1997, the U.S. government (NIST, actually), solicited candidate algorithms for this standard. By June 1998 (the submission deadline), NIST received fifteen submissions. NIST asked for comments on these algorithms, with the intention of pruning the list to five finalists. NIST held an AES conference in Rome in April (this was the second AES conference, the first was the previous August in California), the comment deadline was in June, and last Monday NIST announced the finalists…
Biometrics: Uses and Abuses
Biometrics are seductive. Your voiceprint unlocks the door of your house. Your iris scan lets you into the corporate offices. You are your own key. Unfortunately, the reality isn’t that simple.
Biometrics are the oldest form of identification. Dogs have distinctive barks. Cats spray. Humans recognize faces. On the telephone, your voice identifies you. Your signature identifies you as the person who signed a contract.
In order to be useful, biometrics must be stored in a database. Alice’s voice biometric works only if you recognize her voice; it won’t help if she is a stranger. You can verify a signature only if you recognize it. To solve this problem, banks keep signature cards. Alice signs her name on a card when she opens the account, and the bank can verify Alice’s signature against the stored signature to ensure that the check was signed by Alice…
Cryptography: The Importance of Not Being Different
Suppose your doctor said, “I realize we have antibiotics that are good at treating your kind of infection without harmful side effects, and that there are decades of research to support this treatment. But I’m going to give you tortilla-chip powder instead, because, uh, it might work.” You’d get a new doctor.
Practicing medicine is difficult. The profession doesn’t rush to embrace new drugs; it takes years of testing before benefits can be proven, dosages established, and side effects cataloged. A good doctor won’t treat a bacterial infection with a medicine he just invented when proven antibiotics are available. And a smart patient wants the same drug that cured the last person, not something different…
Why the Worst Cryptography is in the Systems that Pass Initial Analysis
Imagine this situation: An engineer builds a bridge. It stands for a day, and then collapses. He builds another. It stands for three days, and then collapses. Then, he builds a third, which stands for two weeks but collapses during the first rainstorm. So he builds a fourth. It’s been standing for a month, and has survived two rainstorms. Do you believe this fourth bridge is strong, secure and safe? Or is it more likely just another accident waiting to happen?
As bizarre as it may seem, this kind of design process happens all the time in cryptography, a field that is full of people who love to design their own algorithms and protocols. With so many aspiring cryptanalysts out there, however, there’s bound to be a lot of weak designs. The problem is this: Anyone, no matter how unskilled, can design an algorithm that he himself cannot break. Though a competent cryptanalyst can break most of this stuff after a short review, the rest of it survives, and in most cases is never looked at again (especially outside the military world). But just because an algorithm survives an initial review is no reason to trust it…
Intel's Processor ID
Last month Intel Corp. announced that its new processor chips would come equipped with ID numbers, a unique serial number burned into the chip during manufacture. Intel said that this ID number will help facilitate e-commerce, prevent fraud and promote digital content protection.
Unfortunately, it doesn’t do any of these things.
To see the problem, consider this analogy: Imagine that every person was issued a unique identification number on a national ID card. A person would have to show this card in order to engage in commerce, get medical care, whatever. Such a system works, provided that the merchant, doctor, or whoever can examine the card and verify that it hasn’t been forged. Now imagine that the merchants were not allowed to examine the card. They had to ask the person for his ID number, and then accept whatever number the person responded with. This system is only secure if you trust what the person says…
Security in the Real World: How to Evaluate Security
The following remarks are excerpted from a general session presentation delivered at CSI’s NetSec Conference in St. Louis, MO, on June 15th, 1999.
At Counterpane Systems, we evaluate security products and systems for a living. We do a lot of breaking of things for manufacturers and other clients. Over the years, I’ve built a body of lore about the ways things tend to fail. I want to share my “top 20 list” of what’s wrong with security products these days.
Cryptography is a really neat technology, because it allows us to take existing business and social constructs from the real world and move them into the world of computer networks. This is actually the big idea of cryptography. It doesn’t do anything new, it doesn’t do anything magical…
Sidebar photo of Bruce Schneier by Joe MacInnis.