Crypto researchers are preparing to scatter the ashes of a class of Discrete Logarithm Problems (DLPs) as the future of security, following a claim by Swiss researchers to have cracked a 128-bit crypto scheme in two hours.
So as not to frighten the horses, The Register will start by pointing out that our understanding of this paper at Arxiv doesn't mean the schemes you're now using have been broken. Rather, the work by researchers at EPFL in Switzerland excludes crypto based on “supersingular curves” from future consideration.
As the Lausanne-based polytechnic states in its media release, “Whereas it was believed that it would take 40,000 times the age of the universe for all computers on the planet to do it”, the supersingular curve DLP algorithm only lasted two hours on the 24-core cluster used to crack it.
Authored by Robert Granger and Thorsten Kleinjung of EPFL's LACAL (Laboratory for Cryptologic Algorithms) and Jens Zumbrägel of TU Dresden, the paper says this about the cracking of supersingular curves:
“When initially proposed, these fields were believed to be 128-bit secure, and even in light of the recent algorithmic advances, were believed to be 128-bit and 94.6-bit secure. On the contrary, we have shown that the former field has only59 bits of security and we have implemented a total break of the latter. Since asymptotically more efficient techniques can be brought to bear as bit lengths increase, we conclude that small characteristic pairings at all security levels should now be regarded as completely insecure.”
Their results are to be presented at IACR Crypto 2014 conference. ®