[tialaramex]

Trust infrastructures are always like this, it's one reason PGP's "Web of trust" doesn't work at scale.

If you trust Alice then it's not astonishing that Alice can stab you in the back. Most of us can probably manage to pick trustworthy direct friends. But then, what if we're to trust that Alice's friends won't betray us ? That's a lot stickier.

PGP tries to distinguish "Do you trust that Alice is who she says she is?" from "Do you trust that Alice is a good judge of character?" but the latter is largely unknowable and PGP treats it as recursive. You trust Alice, Alice trusted Bob, Bob trusted Caroline and now Caroline's friend Dave stabbed you in the back. How is this Alice's fault somehow?

[somat]

How is that better or worse than the "I trust everyone my authority trusts" mechanism the authority system uses?

[tialaramex]

Having a handful of authorities means we can direct our limited resources at scrutinizing those authorities. Which we do, to great effect. It's not perfect, such a system will never be perfect, but it keeps improving. It's a lot better in 2026 than it was in 2016, and it was a lot better in 2016 than in 2006. In 1996 this is all new and the CAs have basically no idea what they're doing, what's a domain name? Their employees aren't using Tim's toy hypermedia service, it's for nerds.

The resources available to check that Edith's friend Frank's cousin Gerald is trustworthy are zero and when trusting Gerald goes badly, what do we do? "Oh, huh, be more careful"? It's not actionable at all.