RSA Secret-Key Challenge
Encyclopedia
The RSA Secret-Key Challenge consisted of a series of cryptographic contests organised by RSA Laboratories with the intent of helping to demonstrate the relative security of different encryption algorithms. The challenge ran from 28 January 1997 until May 2007.
used for encryption. To win, a contestant would have had to break the code by finding the original plaintext and the cryptographic key that will generate the posted ciphertext from the plaintext. The challenge consisted of one DES
contest and twelve contests based around the block cipher RC5
.
Each of the RC5-* contests is named after the variant of the RC5
cipher used. The name RC5-w/r/b indicates that the cipher used w-bit words, r rounds, and a key made up of b bytes. The contests are often referred to by the names of the corresponding distributed.net projects, for example RC5-32/12/9 is often known as RC5-72 due to the 72-bit key size.
The first contest was DES Challenge III (and was also part of the DES Challenges
), and was completed in just 22 hours 15 minutes by distributed.net and the EFF
's Deep Crack
machine.
In May 2007 RSA Laboratories announced the termination of the challenge, stating that they would not disclose the solutions to the remaining contents, and nor would they confirm or reward prize money for future solutions. On 8 September 2008 distributed.net
announced that they would fund a prize of $4000 for the RC5-72 contest.
group, which had actively participated in the challenge by making use of distributed computing
to perform a brute force attack
.
RC5-32/12/7 was completed on 19 October 1997, with distributed.net finding the winning key in 250 days and winning the US$10,000 prize. The recovered plaintext was: The unknown message is: It's time to move to a longer key length.
RC5-32/12/8 also carried a US$10,000 prize and was completed by distributed.net on 14 July 2002. It took the group 1,757 days to locate the key, revealing the plaintext: The unknown message is: Some things are better left unread.
There were still eight remaining contests that had not yet been solved, RC5/32/12/9 through to RC5/32/12/16, each of which was a US$10,000 prize. Distributed.net had been working on RC5-32/12/9 and were over 1.950% through as of October 27, 2011.
Contest details
For each contest, RSA had posted on its website a block of ciphertext and the random initialization vectorInitialization vector
In cryptography, an initialization vector is a fixed-size input to a cryptographic primitive that is typically required to be random or pseudorandom...
used for encryption. To win, a contestant would have had to break the code by finding the original plaintext and the cryptographic key that will generate the posted ciphertext from the plaintext. The challenge consisted of one DES
Data Encryption Standard
The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...
contest and twelve contests based around the block cipher RC5
RC5
In cryptography, RC5 is a block cipher notable for its simplicity. Designed by Ronald Rivest in 1994, RC stands for "Rivest Cipher", or alternatively, "Ron's Code"...
.
Each of the RC5-* contests is named after the variant of the RC5
RC5
In cryptography, RC5 is a block cipher notable for its simplicity. Designed by Ronald Rivest in 1994, RC stands for "Rivest Cipher", or alternatively, "Ron's Code"...
cipher used. The name RC5-w/r/b indicates that the cipher used w-bit words, r rounds, and a key made up of b bytes. The contests are often referred to by the names of the corresponding distributed.net projects, for example RC5-32/12/9 is often known as RC5-72 due to the 72-bit key size.
The first contest was DES Challenge III (and was also part of the DES Challenges
DES Challenges
The DES Challenges were a series of brute force attack contests created by RSA Security for the purpose of highlighting the lack of security provided by the Data Encryption Standard.-The Contests:...
), and was completed in just 22 hours 15 minutes by distributed.net and the EFF
Electronic Frontier Foundation
The Electronic Frontier Foundation is an international non-profit digital rights advocacy and legal organization based in the United States...
's Deep Crack
EFF DES cracker
In cryptography, the EFF DES cracker is a machine built by the Electronic Frontier Foundation in 1998 to perform a brute force search of DES cipher's key space — that is, to decrypt an encrypted message by trying every possible key...
machine.
In May 2007 RSA Laboratories announced the termination of the challenge, stating that they would not disclose the solutions to the remaining contents, and nor would they confirm or reward prize money for future solutions. On 8 September 2008 distributed.net
Distributed.net
distributed.net is a worldwide distributed computing effort that is attempting to solve large scale problems using otherwise idle CPU or GPU time. It is officially recognized as a non-profit organization under U.S...
announced that they would fund a prize of $4000 for the RC5-72 contest.
Distributed.net
The contests are associated with the distributed.netDistributed.net
distributed.net is a worldwide distributed computing effort that is attempting to solve large scale problems using otherwise idle CPU or GPU time. It is officially recognized as a non-profit organization under U.S...
group, which had actively participated in the challenge by making use of distributed computing
Distributed computing
Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...
to perform a brute force attack
Brute force attack
In cryptography, a brute-force attack, or exhaustive key search, is a strategy that can, in theory, be used against any encrypted data. Such an attack might be utilized when it is not possible to take advantage of other weaknesses in an encryption system that would make the task easier...
.
RC5-32/12/7 was completed on 19 October 1997, with distributed.net finding the winning key in 250 days and winning the US$10,000 prize. The recovered plaintext was: The unknown message is: It's time to move to a longer key length.
RC5-32/12/8 also carried a US$10,000 prize and was completed by distributed.net on 14 July 2002. It took the group 1,757 days to locate the key, revealing the plaintext: The unknown message is: Some things are better left unread.
There were still eight remaining contests that had not yet been solved, RC5/32/12/9 through to RC5/32/12/16, each of which was a US$10,000 prize. Distributed.net had been working on RC5-32/12/9 and were over 1.950% through as of October 27, 2011.