This Self Taught Programmer Solved MIT's 20-Yr-Old Cryptographic Puzzle

A Belgian self-taught programmer has solved MIT’s 20-year-old cryptographic puzzle designed by Ron Rivest who is one of the pioneers in RSA cryptographic protocol and, in fact, the R in RSA was taken from his name.

In 1999, a time capsule with a puzzle designed by Rivest was delivered to the famous architect Frank Gehry to design MIT’s Computer Science and Artificial Intelligence Lab, which is now known as CSAIL. The time capsule consisted of 50 rare items contributed by the likes of internet founder Sir Tim Berners Lee and Microsoft founder Bill Gates.

Ron Rivest designed the puzzle in a manner that would take exactly 35 years to compute a solution for it. However, Bernard Fabrot, a self-taught programmer from Belgium has solved the forgotten puzzle 15 years earlier than expected.

What’s the puzzle?

The puzzle involved computing the number that would result from running a squaring operation 80 trillion times — for example, squaring 2 results into 4, squaring 4 results into 16 and so on. The answer to the puzzle was to be obtained by repeating this process 80 trillion times.

This resultant number would then be combined with a number given in the time capsule. The final result would produce a congratulatory phrase which would be used for opening the time capsule.

No parallel computing, only sequential operations

What makes this cryptographic puzzle tough is the fact that you cannot arrive at the answer faster by parallel computing. It requires sequential computing which is a time-consuming task. Rivest used Moore’s law to ensure that it would take exactly 35 years to compute an answer for it.

How did Fabrot solve it?

Fabrot, who stumbled upon the puzzle accidentally in 2015, solved the puzzle using a consumer PC running on an Intel Core i7-6700 processor. He applied GNU Multiple Precision Arithmetic Library (GMP) which is a free software written in C language.

He spent three years solving the puzzle and said that his computer was running 24×7 to obtain the answer except when he went out for vacations or during power cuts.