Quantum algorithms to find collisions
The reality, however, is that the CNS algorithm is not an efficient way to find collisions. In fact, it’s so inefficient that it’s beaten by the standard non-quantum method of finding collisions, namely “parallel rho” collision search from 1997 van Oorschot–Wiener. Let’s take an in-depth look at what’s going on here.
Besides the beatdown, some good notes on finding collisions and performance assessment. Not always as simple as big O.