> The biggest problems with PKI are that there are too many CAs, who can each go rogue, and that X509 is a horrifically awful format that takes a gigantic TCB t

> The biggest problems with PKI are that there are too many CAs, who can each go rogue, and that X509 is a horrifically awful format that takes a gigantic TCB to parse. Mitigations include browsers firing CAs and severely impacting their business (so effectively, there is regulation), certificate transparency and more and more testing. Those are problems with XPKI, not with PKI in general. SPKI (RFCs 2692 & 2693) fixed them both — it really should have been picked up. It could be used to ensure that you really are talking to someone authorised to use a particular IP address and host name; it also uses a much lighter format than X.509's ASN.1 (and it's human-readable to boot!). I encourage anyone building a modern protocol to take a look at SPKI. Some parts of it need to be modernised, but that's easily-enough done. I'm not so worried about DNSSEC needing to trust TLD & root servers, because with domain-verified certs that's all you get anyway. I contend that domain verification (and IP verification, which to my knowledge no-one does) is good enough for most of what most of us need or want, and the customised SPKI certs could be used for the edge cases.