10 of 10 people found the following review helpful
- Published on Amazon.com
Brute Force: Cracking the Data Encryption Standard is the story of the life and death of DES (data encryption standard). In the early 1970s, the U.S. government put out an open call for a new, stronger encryption algorithm that would be made into a federal standard, known as FIPS (Federal Information Processing Standard.). Numerous solutions were submitted as the DES candidate, including one from IBM. The IBM solution, originally called Lucifer, was chosen to be used as the encryption algorithm. After that, it became known as DES.
DES is the most widely used method of symmetric data encryption ever created. Its 56-bit key size means that there are roughly 72,000,000,000,000,000 (72 quadrillion) possible encryption keys for any given message. DES was always considered a strong encryption method, but strength is relative.
The strength of an encryption system is measured by how resilient it is against attack. From the outset, it was known that DES was susceptible to brute force attacks. A brute force attack, also known as an exhaustive search is an attack against a cryptosystem in which all possible values for the key are attempted - the bigger the key, the more difficult the attack.
It must be remembered that DES was developed long before desktop computers, so the feasibility of a computer that could perform a brute force attack against DES was rendered so expensive and infeasible that the 56-bit key space (in a 64-bit block) of DES was considered strong enough. In reality, Lucifer actually had an original design of a 128-bit block size and 112-bit key size, but politics got in the way, and DES was created in a crippled state from the onset.
By 1997, DES was cracked, and the start of its downfall had commenced. Brute Force: Cracking the Data Encryption Standard is a firsthand account of how DES was broken. Author Matt Curtin was a member of the DESCHALL team, which was created in response to the RSA Security Inc. RSA Secret Key Challenge. The challenge was to break a DES-encrypted message.
Brute Force comprises two interrelated parts. Part 1 is a short overview of cryptography and encryption. It also details how Curtin first became interested in cryptography in the Bexley, Ohio, public library. Part 1 sets the groundwork for the main subject matter of the book, which is Curtin's diary of how DES was broken via DESCHALL.
The unofficial mantra of DESCHALL was that friends didn't let friends have idle computers. DESCHALL was led by Curtin, Rocke Verser, Matt Curtin, and Justin Dolske, and used an Internet-based distributed computing infrastructure. Since brute force attacks are naturally suited to distributed computing, it made for a perfect testing ground to break DES.
Part 2 details the ups and downs of the project. Designing a software system to crunch up to 72 quadrillion is not a easy task, combined with key server crashes, competitive foreign groups, and the U.S. government on your back, made the travails of DESCHALL a challenging endeavor. The success of DESCHALL was to get as many hosts involved as possible. Given the fact that the CPUs of most computers sit idle for most of their lives, such CPUs were of extreme value to DESCHALL.
While Brute Force can be dry at times (remember, this is a book about cryptography), it does have its humorous moments. Much of DESCHALL occurred in the summer of 1997, and many universities had powerful computers that would sit idle all summer. DESCHALL members attempted to harness that power and were astounded when the computer lab manager of Yale University refused to allow the labs computer to run DESCHALL client software. He stated that the computers had the newest processors in them and that he did not want to wear them out. Furthermore, the lab manager thought that running DESCHALL software would void the warranty with the computer manufacturer due to the undue strain it would place on the processor.
The DESCHALL team was victorious in June 1997 when they finally cracked the RSA Secret Key Challenge after processing about 25% of the 72 quadrillion keys. The message was encrypted with the appropriate message "Strong Cryptography Makes the World a Safer Place". DESCHALL succeeding in starting the beginning of the end of DES, which has since been replaced by the Advanced Encryption Standard (AES).
Brute Force is about as entertaining a read as you will get on cryptography. It provides a detailed account of how DES was taken down and is a interesting read for any student of cryptography and the crypto wars of the 1990s.
6 of 6 people found the following review helpful
- Published on Amazon.com
Matt Curtin has written a fascinating book that courses through the history of cryptography, the power of social networks and the Internet to bring them into being, conquering a technological challenge through altruistic cooperation, the competitive spirit, the government's desire to intrude on its citizen's privacy and battle against government in behalf of individual freedom. It sounds like a lot and it is --- but Curtin is blessed with the ability to write in plain English, thus rendering even the most esoteric technology understandable.
The central story revolves around DES, a 56-bit Data Encryption Standard, adopted by the U.S. government in the early 1980s. Proponents argued that DES was unbreakable because there were 76 quadrillion possible keys. Curtin does a masterful job of providing a brief, but thorough history of cryptography through the ages. He deserves an accolade for this. Cryptography is not simple subject and many writers on the subject presume the reader already knows cryptography. Curtin doesn't make this mistake.
Throughout the 1980s and 1990s, technologists and civil libertarians became increasingly concerned that 56-bit DES wasn't secure enough; that it could be defeated and supposedly confidential data compromised. At the same time, the Clinton administration had banned the export of powerful encryption technology hurting businesses and was demanding that all producers of cryptographic systems provide the government with a key, literally a backdoor, so the government at its whim could access encrypted data. The Clinton White House, of course, claimed that law enforcement needed these powers to protect children from pornography, fight terrorism and the war on drugs.
A commercial firm, RSA, announced cash prizes to the first entities to crack several encryption algorithms. Curtin and a few others resonded by organizing an effort to create a network where computer owners would devote unused CPU resources to an effort to crack DES. That is, they would apply up to 76 quadrillion keys to a message created by RSA in order to be the first to get it done.
The story of this "brute force" effort is the bulk of Curtin's book and is compellingly interesting. It involves technology; the creation and evolution of software designed to test keys against the DES algorithm. Here again, Curtin makes what could be incomprehenisible esoterica clear and interesting to the lay reader. Although I've been involved with the technology for more than 40 years, I feel certain that even those who consider themselves "computer illiterate" would find Curtin's explanation of this effort understandable and interesting.
Curtin's story within the story is how strangers with common interests were allowed to come together and pool their efforts via the Internet. Long before "social networking" became a catch phrase, the power of the Internet to facilitate social interaction and cooperation was demonstrated by efforts such as Curtin's, which was called DESCHALL (DES Challenge).
This is almost as interesting as the technological challenge. Before America Online opened the Internet and, particularly the World Wide Web, to masses of vulgarians, the Internet was a very civilized environment. Serious discussions on every topic imaginable took place on Usenet (a form of bulletin board in simplistic terms)with a moderately high degree of decorum ("netiquette). That collegiality was largely lost when every moron got a modem.
There is a sub-story here about competition between DESCHALL, a European effort (SolNET) and others to be the first to crack DES.
Finally there is the political story as factions within Congress, the Clinton White House, business and interested citizens battled over the question of whether American citizens would be allowed to protect the confidentiality of their own information against the government.
Overall, Curtin has done a simply superb job of taking complex technological and political issues and describing them in an undestandable and compelling way. He writes of the DESCHALL quest in a journal style, racheting up the tension as the project encounters and overcomes obstacles, builds a network of volunteers, tries to get press attention and sweats out the competition to be the first to break DES. It's a neat story and well done.
I have only one criticism of the book (other than the occasional editing lapse): the introduction by John Gilmore, a founder of the Electronic Frontier Foundation, is utterly out of place in this book. It is a political rant for the tinfoil hat brigade, ending with a blatant political pitch that is based on misstatements.
Ironically Gilmore writes "[w]e will continue to be surprised by the capabilities that human societies have, when thousands of people network through their computers to accomplish a common purpose." What Mr. Gilmore and his ilk don't get is that it is not just good and decent people like Matt Curtin and his colleagues who engage in such collaboration. Gilmore apparently doesn't comprehend that there is evil in this world and it must be fought.
The inclusion of Gilmore's political ranting, however, does nothing to diminish the value of Curtin's story, which I think deserves to be ranked with other classics of the history of the technology, such as "Fire in the Valley: The Making of the Personal Computer" and other more substantial histories.