The Cipher Challenge
By Doug Peterson
You have to wonder…What were the neighbors thinking? Over the span of two years, author Simon Singh would periodically carry loads of secret papers into his garden, dip them in molten wax, and set them on fire.
Singh was destroying the notes that he used to create the Cipher Challenge, a 10-part set of ciphers presented in the back of his best-selling book The Code Book. He said that while he was developing the ciphers, he wondered whether anyone would really take up his codebreaking challenge. But as it turned out, "If you encrypt it, they will come."
The response to the Cipher Challenge was overwhelming.
For 13 months after Singh issued his challenge, thousands of amateur and professional codebreakers across the world tested their cryptographic cleverness on his 10 ciphers. Web groups, one as large as 2,500 people, bounced ideas back and forth, while the official Cipher Challenge website tracked progress with a leader board.
In the end, a team of Swedish cryptanalysts cracked all 10 stages of the Cipher Challenge in October of 2000, and they came away with the prize - a $15,000 encrypted check.
In a special CSL Golden Anniversary lecture, Singh took listeners behind the scenes of the Cipher Challenge and, in so doing, provided a concise history of cryptography. After all, the 10 stages of the Cipher Challenge consisted of 10 different ciphers from 10 different periods of codebreaking history.
The first stage of the cipher, for example, was a substitution cipher, in which each letter in the secret message was replaced by a corresponding letter from a scrambled alphabet. By using frequency analysis, this cipher was easily cracked.
In some ways, the second stage was even easier to crack, Singh said, because it was encrypted with a Caesar shift - a simple substitution method used by Julius Caesar. Unfortunately, many codebreakers tripped up on this stage because they assumed that all of Singh's encrypted messages would be in English. The Caesar-shift message had been fittingly written in Latin.
Nevertheless, the first four stages of the Cipher Challenge still disappeared in a matter of weeks. A 14-year-old girl and a medical researcher cracked these ciphers simultaneously and were, for the moment, the leaders.
But then came Stage 5, which posed one of the biggest challenges of all.
Stage 5 was a book cipher, in which a particular passage in a particular book is used to encrypt the message. The trick is deducing what book was used as the code's key.
When two people from Cambridge University, working separately, were the first to break Stage 5, rumors began to fly about which publication had been used to create the book code. Many noted that Singh had done his doctorate at Cambridge, "so for the first time ever people were asking to look at my PhD thesis," he said.
As it turned out, however, Singh did not base the Stage 5 code on his PhD thesis. He had used a passage from his earlier best-seller, Fermat's Enigma, to create the book code.
Singh created his Stage 8 cipher using a "virtual Enigma machine" - a computer simulation of the famous cipher machine used by the Germans in World War II. And Stage 9 was encrypted with DES - a popular 56-bit encryption method developed in the 1970's.
The final and most difficult stage was a message encrypted with RSA - the current cryptography standard. To make this cipher easier to break, Singh used a combination of RSA and what is called "Triple DES."
But Singh didn't realize just how simple he had inadvertently made this stage. The winning Swedish team pointed out that he had made a major mistake in the way he used the Triple DES encryption. If they had noticed the mistake earlier, they would have been able to crack Stage 10 in a single day, rather than the months it actually took.
Singh used this blooper to underscore the constant threat of human error.
As he put it, "You can talk about how mathematically perfect an encryption system is. But in the end of the day, these systems are used by people."
By Doug Peterson
You have to wonder…What were the neighbors thinking? Over the span of two years, author Simon Singh would periodically carry loads of secret papers into his garden, dip them in molten wax, and set them on fire.
Singh was destroying the notes that he used to create the Cipher Challenge, a 10-part set of ciphers presented in the back of his best-selling book The Code Book. He said that while he was developing the ciphers, he wondered whether anyone would really take up his codebreaking challenge. But as it turned out, "If you encrypt it, they will come."
The response to the Cipher Challenge was overwhelming.
For 13 months after Singh issued his challenge, thousands of amateur and professional codebreakers across the world tested their cryptographic cleverness on his 10 ciphers. Web groups, one as large as 2,500 people, bounced ideas back and forth, while the official Cipher Challenge website tracked progress with a leader board.
In the end, a team of Swedish cryptanalysts cracked all 10 stages of the Cipher Challenge in October of 2000, and they came away with the prize - a $15,000 encrypted check.
In a special CSL Golden Anniversary lecture, Singh took listeners behind the scenes of the Cipher Challenge and, in so doing, provided a concise history of cryptography. After all, the 10 stages of the Cipher Challenge consisted of 10 different ciphers from 10 different periods of codebreaking history.
The first stage of the cipher, for example, was a substitution cipher, in which each letter in the secret message was replaced by a corresponding letter from a scrambled alphabet. By using frequency analysis, this cipher was easily cracked.
In some ways, the second stage was even easier to crack, Singh said, because it was encrypted with a Caesar shift - a simple substitution method used by Julius Caesar. Unfortunately, many codebreakers tripped up on this stage because they assumed that all of Singh's encrypted messages would be in English. The Caesar-shift message had been fittingly written in Latin.
Nevertheless, the first four stages of the Cipher Challenge still disappeared in a matter of weeks. A 14-year-old girl and a medical researcher cracked these ciphers simultaneously and were, for the moment, the leaders.
But then came Stage 5, which posed one of the biggest challenges of all.
Stage 5 was a book cipher, in which a particular passage in a particular book is used to encrypt the message. The trick is deducing what book was used as the code's key.
When two people from Cambridge University, working separately, were the first to break Stage 5, rumors began to fly about which publication had been used to create the book code. Many noted that Singh had done his doctorate at Cambridge, "so for the first time ever people were asking to look at my PhD thesis," he said.
As it turned out, however, Singh did not base the Stage 5 code on his PhD thesis. He had used a passage from his earlier best-seller, Fermat's Enigma, to create the book code.
Singh created his Stage 8 cipher using a "virtual Enigma machine" - a computer simulation of the famous cipher machine used by the Germans in World War II. And Stage 9 was encrypted with DES - a popular 56-bit encryption method developed in the 1970's.
The final and most difficult stage was a message encrypted with RSA - the current cryptography standard. To make this cipher easier to break, Singh used a combination of RSA and what is called "Triple DES."
But Singh didn't realize just how simple he had inadvertently made this stage. The winning Swedish team pointed out that he had made a major mistake in the way he used the Triple DES encryption. If they had noticed the mistake earlier, they would have been able to crack Stage 10 in a single day, rather than the months it actually took.
Singh used this blooper to underscore the constant threat of human error.
As he put it, "You can talk about how mathematically perfect an encryption system is. But in the end of the day, these systems are used by people."
Simon Singh
Best-selling author of The Code Book and Fermat's Enigma
BBC director of an award-winning documentary on Fermat's Last Theorem, which aired on PBS's "Nova" series.
Presentation Title: ""Ocz Nzxmzo Cdnomt ja Kpwgdx Fzt Xmtkojbmvkct"
Delivered:
April 6, 2001
Best-selling author of The Code Book and Fermat's Enigma
BBC director of an award-winning documentary on Fermat's Last Theorem, which aired on PBS's "Nova" series.
Presentation Title: ""Ocz Nzxmzo Cdnomt ja Kpwgdx Fzt Xmtkojbmvkct"
Delivered:
April 6, 2001
