For anyone else who's wondering what PSP is, from the Google spec[1]:
The PSP Security Protocol (PSP) is a security protocol created by Google for encryption in
transit. PSP uses several of the concepts from IPsec ESP to provide an encryption
encapsulation layer on-top of IP that is streamlined and custom-built to address the
requirements of large-scale data centers.
So "PSP" really is a recursive acronym for "PSP Security Protocol". eyeroll
[1] https://raw.githubusercontent.com/google/psp/main/doc/PSP_Ar...