PGP algorithm exists for a long time. It seems to me that it has been already hacked repeatedly, so it isnt rational to use it in STEEL ecosystem.
There have been no known cases of crack of an PRG protocol carried out with the help of cryptographic or computing methods. If you find the info about real case of crack, please tell the platform representatives about it.
However, why hasnt this algorithm become popular if it is so effective? Theres smthng screwy about the matter.