Single-use seal primitive over Bitcoin blockchain

[dr-orlovsky]

Single-use seal primitive over Bitcoin blockchain

Motivation

Single-use seal is a generic concept preventing double-definition or double-action (like double-spend), originally proposed by Peter Todd [1]. This specification defines how single-use seals can be constructed on top of bitcoin blockchain.

Background

Single use seal is a non-mathematical commitment primitive that allows to pick the fact after the commitment.

Single use seal (or seal) is a replicative state (or consensus?) primitive that allows to define a option for a future commitment (lazy commitment) to some value (that even can be not known now), such as:

• the actual commitment to a message can happen once and only once;
• the event of the promise fulfillment (i.e. the actual commitment being made) can be proved to independent parties.

Single-use seal may be used to define some value (or, with usage of cryptographic digests, message) to be defined in the future only once, and prevents an inconsistent view on a historical state. A party which would like to prove the event of the commitment must present a witness of the seal being closed over the message.

[implementation-specific]
The parties sharing the same single-use seal before it's creation must agree on a set of the global parameters, namely:

• deterministic single location of the seal in that medium
• cryptographic commitment function
• deterministic definition of the witness for the seal closing

Specification

Single-use seal is defined as a tuple of parameters S_opened=(txid, vout, commitment_scheme, deterministic_commitment_txout_locator). When the seal is closed, it is closed over a value V (which may be just an integer value or a value of cryptographic hash function), so `S_closed=(S_opened, V).

struct Seal {
    txid: Txid,
    vout: u16,
}

trait Sealer<V> {
    fn close(&self, value: V, witness: &mut Transaction);
    fn verify(&self, value: V, bitcoin_blockchain: BitcoinFullNodeAPI) -> Result<V, Error>;

    // Used by the close function internally:
    fn commitment_applicator(&self,  commiting_txout: &mut TxOut);
    fn commitment_locator(&self, witness: &Transaction) -> &TxOut;
}

References

1: https://petertodd.org/2017/scalable-single-use-seal-asset-transfer

[dr-orlovsky]

closed by https://github.com/LNP-BP/LNPBPs/blob/master/lnpbp-0010.md