No, quantum computers are not about to destroy the security of encryption systems. I have been seeing loads of noise about that, and it’s not true. To break encryption systems, you need to be able to factor numbers with thousands of digits to break cryptography and we have been stuck with quantum computers being able to factor two digits for 25 years now. 21 is the largest number ever cleanly factored by a quantum computer, and you can do that in your head in a moment, it’s 3 times 7. This graph is on a log scale (linear in digits), but it would be pretty much the same silly flat line on a linear scale. You need to be able to handle 1200 digits, but I will settle for being interested again when someone can factor 91 with a quantum computer. Now, a schoolchild can factor 91, it’s 7 x 13, but it would at least represent progress over the current record, which as I said is 21. (And yes, for the pedants out there, elliptic curve systems are a bit different but it’s the same principle.)