A cryptographic identity is a public key as used in a public key signature scheme. So a particular person is represented by a ridiculously long number. That number can be shortened with some sort of hash to a shorter value to make a key fingerprint, which is a shorter ridiculously long number. The scheme described in the system seems to use a blockchain to create a shared mapping between a name and a cryptographic id…
> most of them would have to conspire to forge a mapping.
The mapping is recorded in an immutable ledger (bitcoin) so forging is not feasible without breaking Bitcoin's proof of work. its a stronger guarantee than a key server.
> They instead want to be sure that they are securely exchanging messages with an particular flesh and blood person
comparing fingerprints doesn't verify a flesh-and-blood human either. "is this the specific person I mean" problem is still real and separate though.
`grace@key` binding gives you a stable, human-readable identifier you can hand out like an email address, build reputation on, and that anyone can use to verify posts made by you and message you without having to meet you in person. It solves the UX of using public keys as your identity. You can post online with a public key as your id (e.g. nostr) but its harder to build your online identity around it.
you can rotate the key underneath the name. with a bare key it becomes your identity, so rotating means becoming a new person and re-verifying with everyone.
> you are back in the realm of ridiculously long numbers.
not really. the long number is a disposable part, and there's a name above it. You can still exchange "grace@key" in person, and be sure you're talking to "grace@key"