[icebraining]

The innovation of Bitcoin is combining the Proof-of-Work with a signed ledger. But Proof-of-Work is only needed because otherwise anonymous people might create new nodes from thin air and get a majority.

In this case, all the parties are well identified, so if a new node appears, it can simply be rejected by the existing participants. So there's no need for PoW, all you need is for companies to sign and publish documents to each other. The only possible fraud is publishing different documents to different parties, but that's easily fixable by having the nodes confirm each others' documents.

So yeah, that's just a signed ledger. All invoicing programs in my country had that before Bitcoin even appeared, as part of the SAF-T standard (mandated by our tax authority). It's nothing new.