Pangolin can't afford to hire decent crypto dudes- they are *really* expensive. That's why people use published crypto standards like AES- you don't need to hire world-class cryptographers to implement strong crypto.
If Pangolin were using such a system, they would not need to put a QM in a datacenter- they could just give Pieter the appropriate private key, maybe even embedded in some secure hardware like a smartcard or a USB cryptostick.
It isn't. It got cracked recently- that's what all the trapdoored FB3 firmware upgrades were about.