Key Concepts and Terminology

Attestation

When submitting an epoch solution, miners must attest to state from 4 epochs ago (~21 blocks deep). This ensures the attested state is already immutable in Bitcoin's history.

Checksum Root

A cryptographic fingerprint of the entire epoch's final state. Every balance, every contract's storage, every bit of data. If anything differs by a single bit, the checksum root changes completely.

Consensus Layer

An external system that observes a base layer blockchain's blocks and derives deterministic state according to its own ruleset, without requiring modifications to the base layer protocol. OP_NET is the first implementation of this pattern.

A consensus layer inherits the parent chain's security and can only be more secure, never less.

Deterministic Ordering

OP_NET sorts transactions within each block by: gas price, then priority fees, then transaction ID. This canonical ordering ensures all nodes process transactions in the same order.

Epoch

Five consecutive Bitcoin blocks (~50 minutes). All OP_NET transactions confirmed during an epoch become part of that epoch's state. At epoch end, a checksum root is computed and miners compete to checkpoint it.

Gas

Computational cost unit for contract execution. Paid in satoshis. The winning epoch miner receives fees from a future epoch, not the one they're mining.

Metaprotocol

A system where indexers interpret data embedded in transactions. Different indexers can show different results because there's no mechanism forcing agreement. Examples: BRC-20, Runes, Alkanes.

OP_NET is NOT a metaprotocol. It provides cryptographic proof of correct execution.

ML-DSA

Module-Lattice Digital Signature Algorithm. A NIST-standardized post-quantum signature scheme. OP_NET requires ML-DSA for all contract interactions, adding quantum-resistant security on top of Bitcoin's ECDSA.

OP_VM

OP_NET's WebAssembly virtual machine. Executes smart contracts deterministically. Given the same code and inputs, every node computes the same result. Gas-metered to prevent infinite loops.

P2OP

Pay-to-OP_NET. Custom address format for smart contracts using SegWit version 16 (OP_16) with a custom HRP. Encoded with Bech32m. Example: opnet1s...

SHA-1 Epoch Mining

Miners compete to find SHA-1 near-collisions with the previous epoch's checksum root. This determines reward distribution only. Miners cannot influence consensus. If nobody mines, the genesis block hash becomes the epoch miner.

Single Honest Node

OP_NET needs only ONE honest node to maintain validity. All state is deterministically derived from Bitcoin blocks. Any node can verify the entire state independently.