It took 3.5 years for Belgian programmer Bernard Fabrot to solve a cryptographic puzzle that was originally thought to take 35 years of computational time. The puzzle is what’s known as a “time-lock problem” – a time-consuming calculation that can only be accelerated by tuning your algorithm or by building faster computer hardware. Time-lock puzzles are interesting, and important, because they can’t be short-circuited simply by splitting the problem into pieces and throwing more computers at it. The puzzle essentially involves doing roughly 80 trillion successive squarings of a starting number, and was specifically designed to foil anyone trying to solve it more quickly by using parallel computing. The puzzle is an example of a “verifiable delay function” (VDF), meaning that its answer can only be solved after a certain number of steps.
In the original announcement, LCS promised that, if a correct solution was uncovered, they would open a special “time capsule” designed by architect Frank Gehry and filled with historical artifacts from the likes of Web inventor Tim Berners-Lee, Ethernet co-inventor Bob Metcalfe, and Microsoft founder Bill Gates. The capsule ceremony will happen Wednesday, May 15 at 4 p.m. at MIT’s Stata Center.