Holochain; extremely simplified

[A gross summarization of how Holochain works.](https://developer.holochain.org/concepts/)

Holochain is a blockchain system that does not rely on proof of work (Bitcoin), proof of stake (Loki, NXT), or central trust delegation (Ripple.) It works on a kind of "trust but verify" system where people run their own software but the software produces a log which can be audited by other users of the same software. Any user can clown their own ledgers but everyone else is capable of detecting the tampering and can choose whether to exile that user.

Data

Each user-program pair has their own public blockchain. They can write new entries in to this at any time. After appending an entry that new piece is distributed to other users on the network via a large distributed hash table. Public-private keys are used so only the owner of the user-program pair can write new events for their chain. Custodial holding of public fragments in the hash table prevents the owner of the keys from modifying their own history and minting a new blockchain undetected.

Private data can be put in to blocks . These blocks are then referenced (via content hashes) in the public chain. This allows you to keep some secret like predicting who the next president will be. The public chain certifies the prediction happened and once the private blocks are published can testify this is the prediction you made and told everyone about.

Thus the only public information is whatever an application publishes. Private state can be maintained indefinitely or revealed at a later date for auditing.

The Program

Users interact with a program in some way. The program then implements the rules for signalling, verifying data, and issuing updates. Other users in the network who use the same version of the program also are able to verify that each other are following the rules.