Keybase is a centralized service but AIUI you don't need to actually trust the centralized Keybase service because all the actual validation is performed client-side (i.e. verifying all the proofs that the people you follow have posted) and all of the changes people make to their profiles are publicly published as a chain that is then periodically embedded into the Bitcoin blockchain.

As long as you're ok with relying on the keybase service being reachable and functional, trust is still decentralized and verifiable.

Depends on what you think of their Blockchain/Merkle tree work, though. The attestation chain that Keybase uses is a public merkle tree, and though currently built to be centrally signed, at the root level, still has some built in decentralized redundancy at the user/client level.

Interesting gray areas between easy determinations of whether or not something is centralized/decentralized or now.

https://keybase.io/docs/server_security

Yup, the "centralized" is what I meant by "modern take".

Yeah, their website says nothing until you hit the docs. But I've found the app quite useful.

Essentially: a keyserver facility where you attest to your keys in public identities (like my hn profile), plus a bunch of end-to-end encrypted stuff built atop of it.