The SKS Keyserver network has been under attack with poisoned
certificates since at least 2019. Downloading a poisoned certificate has
the awful side-effect of completely breaking your keyring and most
software has now moved off the network and uses the keys.openpgp.org
which has a different protocol instead - in fact one whereby emails are
verified.
For more details regarding the attack see: https://gist.github.com/rjhansen/67ab921ffb4084c865b3618d6955275f
See: https://keys.openpgp.org/about and https://keys.openpgp.org/about/faq
Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>