In 1991, the cybersecurity company, RSA Laboratories in Bedford, Massachusetts published a list of 54 increasingly large numbers that it had created by multiplying two prime numbers together. It then challenged the computer science community to factorize them — to find the original prime numbers in each case. The company even offered cash prizes for some of the solutions.
The challenge was designed to assess state-of-the-art capabilities for factoring numbers. That’s important because factoring — or more precisely its difficulty— secures various public key cryptosystems. So advanced factoring capabilities make these cryptosystems less secure.
The challenge ended in 2007 but even today 31 of these RSA numbers remain unfactored. The largest is RSA-2048, so-called because of the number of bits required to represent it.
