Attack which generates gpg keys which match the 32 bits of a target public key.
\begin{quote} GPG usage has grown steadily while the tooling that supports it remains stagnant despite staggering hardware advancement. 32bit key ids were reasonable 15 years ago but are obsolete now. Using modern GPUs, we have found collisions for every 32bit key id in the WOT’s (Web of Trust) strong set. Although this does not break GPG’s encryption, it further erodes the usability of GPG and increases the chance of human error.
Stop using 32bit key ids It takes 4 seconds to generate a colliding 32bit key id on a GPU (using scallion). Key servers do little verification of uploaded keys and allow keys with colliding 32bit ids. Further, GPG uses 32bit key ids throughout its interface and does not warn you when an operation might apply to multiple keys. \end{quote}