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RISCy Docs

Architecture

RISCy Network combines four layers into a single chain: a high-throughput UTXO base layer derived from Nexa, a general-purpose RISC-V virtual machine, eCash-style pre-consensus for instant finality, and Drivechain (BIP-300/301) for Bitcoin-anchored security.

The stack at a glance

LayerProvidesOrigin
Base ledgerUTXO model, parallel validationNexa fork
ExecutionRISC-V smart-contract VMRISCy addition
FinalityInstant finality via pre-consensuseCash
SecurityDrivechain hashrate escrow (BIP-300/301)RISCy addition
Native coinRISCYRISCy

1. Base layer — Nexa-derived UTXO

RISCy’s base layer is a fork of Nexa, whose protocol is itself a modification of Bitcoin Cash (and, in turn, Bitcoin). Key inherited properties:

  • UTXO ledger. State is held in unspent transaction outputs rather than a single global account state. This enables parallel transaction validation — there is no global-state bottleneck.
  • Proof-of-Work consensus. Block ordering uses a PoW hash that combines elliptic-curve multiplication with SHA-256, targeting a 2-minute block time.
  • Schnorr signatures over the secp256k1 curve.
  • Pay-to-Script-Template addresses and a native token / group system.
  • A peer-to-peer (P2P) overlay network for transaction and block propagation.

See the Nexa specification for full base-layer detail. Parameters RISCy may tune before mainnet are marked TBD elsewhere in these docs.

2. Execution layer — RISC-V VM

On top of the UTXO base layer, RISCy adds a general-purpose RISC-V virtual machine. Contracts are compiled to standard RISC-V bytecode — not a proprietary format or an EVM-compatibility layer — so any language that targets RISC-V (Rust, C, Zig, and more) can run on RISCy.

Because execution sits on a UTXO model, contract logic is enforced through script templates rather than a single mutable global state. The detailed mapping between the RISC-V VM and the UTXO model is TBD and will be documented in the Contracts section.

3. Finality layer — pre-consensus

RISCy uses pre-consensus, the Avalanche-based voting layer pioneered on eCash, to deliver instant finality. Nodes rapidly agree on the order and validity of transactions before they are buried in blocks, producing a Nakamoto / Avalanche hybrid:

  • Nakamoto (PoW) provides long-term ordering and security.
  • Avalanche pre-consensus provides fast convergence and irreversible settlement in seconds.

This removes reorg risk for confirmed transactions and enables Web2-like responsiveness. For a full explanation, see Instant Finality.

RISCy’s specific finality timing and validator/stake parameters are TBD.

4. Security layer — Drivechain

RISCy is secured by Bitcoin miners via Drivechain:

  • BIP-300 (Hashrate Escrow). Lets the sidechain inherit Bitcoin’s security budget through a hashrate-escrow mechanism.
  • BIP-301 (Blind Merged Mining). Lets Bitcoin miners secure RISCy with no additional work and no separate token staking.

This anchors RISCy to Bitcoin-level security while keeping the sidechain independently programmable.

How the layers work together

A simplified transaction lifecycle:

  1. A transaction (optionally invoking a RISC-V contract) is broadcast to the P2P network.
  2. Nodes validate it against the UTXO set — in parallel where possible.
  3. Pre-consensus quickly converges on its validity and ordering, giving the user instant finality.
  4. The transaction is included in a PoW block.
  5. Drivechain anchors the chain’s security to Bitcoin miners over time.

The precise interaction between pre-consensus, the RISC-V VM, and block production is TBD and will be expanded here.

Economics

  • The native coin is RISCY, used for fees.
  • Builders can capture up to 70% of the fees their contracts generate, paid directly on-chain. Exact mechanics are TBD — see Contracts.

Next steps