Originally I meant author of the piece who would confirm the sale. But basically anyone who feels like writing into the commit log, which can be a creator, a consumer for confirmation, a trustee or a clearing entity that creates merge commits. Even multiple commits by the same person are thinkable if there are handshakes.

> The whole point of a blockchain is for people who can’t trust each other.

I guess that's a very valid point and from my understanding the anonymity baked in is quite unique. And yet, even if I bought say coffee from an independent online market. Probably it's good to have a chain of trust to the seller to know that it's high quality. (Like Amazon reviews)

After all this is what GPG or x509 provide, a chain of trust.