Brute Force 76
ijones writes "Brute Force, by Matt Curtin, is about an event that
many Slashdotters will remember: the cracking of the Data Encryption
Standard. In June of 1997, a 56-bit DES
key was discovered, and its encrypted
message decoded, by an ad-hoc distributed network of computers,
cooperating over the Internet. Four and a half months earlier, RSA had issued a challenge to the
cryptography community, offering $10,000 to the first group to crack a
56-bit DES encrypted message. In Brute Force, Matt
Curtin offers his first-hand account of the DESCHALL team's winning
effort." Read on for the rest of Jones' review.
| Brute Force: Cracking the Data Encryption Standard | |
| author | Matt Curtin |
| pages | 291 |
| publisher | Copernicus Books |
| rating | 9 |
| reviewer | Isaac Jones |
| ISBN | 0387201092 |
| summary | Volunteers working collaboratively over the internet manage to crack the Data Encryption Standard. |
Although I wasn't involved with the DES cracking challenge, I am friends with the author of this book. I took a Lisp course from Matt at Ohio State University and I'll be forever grateful that Matt introduced me to functional programming with a great deal of humor and enthusiasm. I don't think I've ever seen Matt stay so serious for so long, but his enthusiasm comes through clearly in this book.
Brute Force can be enjoyed by both nerds and non-nerds interested in cryptography or codes. Those who have been a part of this or subsequent DES challenges may be particularly interested in this book. Curtin covers some technical details of DES and the brute force attack that the DESCHALL team used to discover a DES key. He also discusses the political and historical significance of this event. This is a fairly technical book, but it goes out of its way to explain non-obvious technical topics, so one doesn't need a lot of technical background to understand it.
Curtin briefly explains a lot of stuff: the C programming language, firewalls, UDP, one-time pads, protected memory, etc., in order to make this book readable for novices. Although I generally did not need such explanations, I did not find them annoying or distracting, as they were fairly brief. In fact, it's fun to read concise explanations of such topics. Occasionally, Curtin does go into just a little too much detail. The chapter on Architecture gives an explanation of some of the many pieces of software that were involved in this effort. This chapter sometimes gets a bit bogged down with explanations of useful scripts that folks wrote to analyze data or forward packets through firewalls.
Brute Force is a very readable and enjoyable book. It is well organized as a narrative, though it is not chronological; Curtin presents the background and substance to each aspect of the story together, rather than chronologically. This can be slightly confusing sometimes, but I think it improves the over-all flow of the story.
In a way, Curtin gives away the ending to the book at the beginning (and in the title), but this isn't ancient history, and most readers will probably already know that DES was defeated by this effort. He still manages to maintain a good sense of suspense throughout the book. He presents tables and analysis of the effort, along with predictions about completion dates that volunteers had made at the time. Unfortunately, he doesn't tell us whether those tables turned out to be correct. What percentage of the keyspace was searched by Macintoshes? How many different kinds of client machines were there in the end? Did Ohio State University try more keys than Oregon State University? Which one is the real OSU?
One of the main themes running throughout the book was that of community. The DESCHALL project was made up of thousands of volunteers from all over the US. Anyone with some spare CPU cycles could get involved by downloading the client software. This may remind you of other distributed computing projects like SETI@home. The community was further broken down into sub-groups like schools who would compete for bragging rights. The organization of the DESCHALL project was much like an open source project, though the key-cracking tools were not open source. Spreading the Word is a chapter about how people started to hear about DESCHALL and what the earliest adopters were like. Some of the tables in a later chapter list the operating system and hardware that the clients were running, which was a pretty cool snapshot of the Internet from 1997. It included lots of OS/2 clients, labs full of SGI machines, and plenty of computers which were only connected to the Internet via dial-up modems. Special scripts were developed for such machines so they could phone home when they needed a new block of keys.
Though the key cracking clients were not open source, they were free as in beer, at least for Americans. Since such cryptography-related software could not be exported at the time, this was a US-only effort. There was a European team, however, with their own software, called SolNet, and Curtin keeps us updated on their progress. In fact the DESCHALL project had an impact on the political debate of this time with regard to the export and control of cryptographic technologies. Curtin gives us interesting periodic updates on the political debate as the DES cracking story moves forward. Cryptography control was defeated at that time, but the use of cryptography is a right that will need continued protection.
The political story of DESCHALL was one aspect of the historical impact of the project. Another impact was the explosion of volunteer distributed computing networks after the DESCHALL project, with SETI@home being one of the most obvious examples. DESCHALL clearly demonstrated the viability of this kind of computation. Curtin touches briefly on this here and there, but does not go into detail. I would like him to more clearly spell out the trends in Internet distributed computing. I would like to hear that DESCHALL was derived from project A and that it inspired projects B, C, and D. Was it was the original Internet distributed computing network? Was it a fad that has abated in the last few years? Curtin touches on this a bit, but says, "Some other distributed computing projects like DESCHALL were around," (pg 200.) He says which ones, but doesn't make any claims that DESCHALL inspired SETI@home, for instance. Perhaps such things are never quite clear in the free exchange of ideas on the Internet.
The political and community aspects of the story wrap up very nicely. Curtin outlines DESCHALL's impact on driving the AES standard, and its (perhaps much smaller) impact on the debates on key escrow and encryption exports. Brute Force is a very enjoyable read about an important event, and I can happily recommend my friend Matt's book to the Slashdot crowd. My only criticisms can really be summed up by saying, "I want to hear more."
You can purchase Brute Force: Cracking the Data Encryption Standard from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Re:Distributed.net (Score:3, Insightful)
Now things like protein folding have much more benefit to the world. Pick your projects carefully.
Botnets. (Score:3, Insightful)
Every time someone mentions brute-force attacks against encrypted data, all I can think of is the growing number of computers that part of remote controlled botnets [wikipedia.org].
I imagine that brute-force encryption attacks by anyone with a direct or indirect connection to a 20,000+ node net are alarmingly easy.
Re:Distributed.net (Score:3, Insightful)
Encryption is generally best when it is an all-or-nothing operation. If you encrypt JUST the one file with sensitive information, you draw attention to it and make it the obvious target.
OTH, if every file in your system is encrypted, it is a lot harder to know which files are important to break, and it will take so many more resources to accomplish.