Audit

Every step of every payment is hash-linked, and the roots are published where nobody can rewrite them.

Why this is worth anything

A log we keep is a log we could edit. Each record hashes the one before it, so a removal or an edit breaks the chain visibly; the root of a batch is then written to a public consensus topic. Anyone can recompute the chain and check it against that root without trusting us, and without us being online.