How The “Conservation of Weirdness” Will Impact Cryptography. Cryptography depends on the supposed difficulty of finding the prime factors of a large number, and a variety of similar computationally hard tasks. RSA and related public key algorithms are believed to be at risk within a decade or two of becoming ineffective. There is still a huge amount of work to be done both in building practical quantum computers and in figuring out what they are actually good for, and broad expertise is needed to make progress. I was inspired to write this post by Scott Aaronson’s suggestion that there is a “Law of Conservation of Weirdness” in quantum computing.