Researchers crack 'unbreakable' 923-bit code
Another seeming "impossibility" has been overcome as researchers in Japan cracked a 923-bit code in a matter of five months, or 148 days.
The researchers said the feat establishes the security of pairing-based cryptography and contributes to its standardization as the next-generation cryptography.
"Until now, cryptanalysis of pairing-based cryptography of this length was thought impossible as it was estimated to take several hundred thousand years to break. Indeed, despite numerous efforts to use and spread this cryptography at the development stage, it wasn't until this new way of approaching the problem was applied that it was proven that pairing-based cryptography of this length was fragile and could actually be broken in 148.2 days," Fujitsu Laboratories Ltd., one of the researchers, said in a news release.
In this case, the 923-bit encryption involved a 278-digit number.
Aside from Fujitsu, the other participants in the research included Japan's National Institute of Information and Communications Technology (NICT) and Kyushu University.
"This result is used as the basis of selecting secure encryption technology, and is proving useful in the standardization of next-generation cryptography in electronic government systems in Japan and international standardization organizations," Fujitsu said.
21 computers, 148.2 days
Fujitsu said the researchers succeeded with the cryptanalysis of the pairing-based cryptography of 278 digits (923 bits) with 21 personal computers (252 cores) in 148.2 days.
It said the cryptanalysis is the equivalent to spoofing the authority of the information system administrator.
"As a result, for the first time in the world we proved that the cryptography of the parameter was vulnerable and could be broken in a realistic amount of time," it said.
It said this was extremely challenging as it required several hundred times computational power compared with the previous world record of 204 digits (676 bits).
"We were able to overcome this problem by making good use of various new technologies, that is, a technique optimizing parameter setting that uses computer algebra, a two-dimensional search algorithm extended from the linear search, and by using our efficient programing techniques to calculate a solution of an equation from a huge number of data, as well as the parallel programming technology that maximizes computer power," it said.
Fujitsu said this may be technical foundation on which to estimate selection of secure encryption technology or the appropriate timing to exchange a key length.
"We will continue to move forward on research that pushes the boundary of the secure use of cryptography," it said.
Fujitsu said much attention has recently been paid to the new "pairing-based" cryptography system, which is being standardized as a next-generation encryption system.
It said such a technology is attractive as it can be used for various useful applications such as identity-based encryption, keyword searchable encryption, and functional encryption - which were impossible using previous public key cryptography.
Fujitsu also said that as cryptanalytic techniques and computers become more advanced, cryptanalytic speed accelerates, while cryptographic security decreases.
Thus, it said it is important to evaluate how long the cryptographic technology can be securely used.
On the other hand, it said pairing-based cryptography has not advanced, so it was premature to evaluate its security against a new attack method. — TJD, GMA News