Maybe. But Cap'n Proto implements a capability-based model which is more web-of-trust than PKI, so arguably a lot of what's in TLS (and a lot of what makes TLS

Maybe. But Cap'n Proto implements a capability-based model which is more web-of-trust than PKI, so arguably a lot of what's in TLS (and a lot of what makes TLS complicated) is irrelevant to it. I agree that people who actually want traditional PKI should use TLS; we're certainly not going to reinvent that. But there's an opportunity to do something much simpler. There's also the issue that Cap'n Proto wants to implement a distributed capability fabric in which machine A may have a capability to an object on machine B and may send that capability to machine C, after which machine C should form a direct connection to machine B in order to make calls on that capability. How to accomplish this (without PKI) is well-known, but it may prove convoluted to build it with TLS as the basic building block. I have to do more research, though.