With IBM, Google, and Microsoft pouring funding into the research of quantum computing, it’s really starting to look like we are going to see the benefits in the next 5 – 10 years. Google may be just weeks from announcing they reached the quantum supremacy milestone and IBM may not be far behind either. Today, I wanted to share my thoughts on how quantum computing may affect cryptography as we know it.
When we talk about the basic cryptography used for things like TLS when you access your bank’s website, the premise behind securing your data is surprisingly simple. The certificate uses a public key which is really just a large number that’s the result of multiplying two prime numbers together. This key has a size typically between 256 bits and 2048 bits. It’s quite a large number. To find the two factors via brute force, in today’s classical computers, it would take a billion years to solve (give or take a year or two). In computational complexity theory, they refer to these problems as intractable. They just can’t be solved with the computers we have today.