Bernard Fabrot (used with permission)

The solution of LCS35 has received considerable media coverage. Among others, Wired (English) and Golem (German) have published articles about it. I have never heard of Bernard Fabrot before. I don’t think he has ever been active in the crypto scene. However, he is not a no-name, as he has written a couple of Linix books in French.

Instead of 35 years, as expexted by Rivest, Fabrot needed only three-and-a-half years for solving LCS35. As it seems, he was only about two weeks faster than a US group named Cryptophage, who worked on the LCS35 challenge, too.

For his computations, Fabrot used the GNU Multiple Precision Arithmetic Library, a free software library written in C for doing precise arithmetic. Fabrot dedicated one of the CPU cores on his home PC to solve the challenge. Wired quotes him: “During all these years I told no one I was trying to solve the puzzle except very close friends. I knew I had a chance, but if I told anyone they could have used a more powerful CPU to overtake me.”

The solution, i.e., the value of w and the plaintext, will be published on May 15th.

Edited to add: Meanwhile I have established contact with Bernard. I will ask him for details.

Further reading: The Top 50 unsolved encrypted messages: 45. The World Record Challenge


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Kommentare (1)

  1. #1 Gerd
    3. Mai 2019

    Note that Fabrot got the result two weeks earlier than the cryptophage project, but his approach was not faster. Fabrot’s C-program was running for 3 and a half years, where the dedicated FPGA-circuit of the cryptophage project needed only two months.
    As a FPGA approach is so much faster, the expected time to solve an encryption using a CPU based computer is not of great value. Codebreakers are not forced to use CPUs for that.