Crate btc_relay

BTC-Relay Pallet

Based on the specification.

This pallet implements a Bitcoin light client to store and verify block headers in accordance with SPV assumptions - i.e. longest chain.

Unless otherwise stated, the primary source of truth for code contained herein is the Bitcoin Core repository, though implementation details may vary.

Overview

The BTC-Relay pallet provides functions for:

• Initializing and updating the relay.
• Transaction inclusion verification.
• Transaction validation.

Terminology

• Bitcoin Confirmations: The minimum number of Bitcoin confirmations a Bitcoin block header must have to be seen as included in the main chain.

• Parachain Confirmations: The minimum number of Parachain confirmations a Bitcoin block header must have to be usable in transaction inclusion verification.

Re-exports

• pub use bitcoin;
• pub use types::OpReturnPaymentData;
• pub use types::RichBlockHeader;
• pub use pallet::*;

Modules

• pallet
  The pallet module in each FRAME pallet hosts the most important items needed to construct this pallet.
• types

Structs

• BtcPublicKey
  Compressed ECDSA (secp256k1 curve) Public Key
• FullTransactionProof
  We also check the coinbase proof in order to defend against the ‘leaf-node weakness’. See https://bitslog.com/2018/06/09/leaf-node-weakness-in-bitcoin-merkle-tree-design/ .
• PartialTransactionProof

Enums

• BtcAddress
  A Bitcoin address is a serialized identifier that represents the destination for a payment. Address prefixes are used to indicate the network as well as the format. Since the Parachain follows SPV assumptions we do not need to know which network a payment is included in.

Constants

• ACCEPTED_MAX_TRANSACTION_OUTPUTS
  Accepted maximum number of transaction outputs for validation of redeem or replace See: https://spec.interlay.io/intro/accepted-format.html#accepted-bitcoin-transaction-format
• DIFFICULTY_ADJUSTMENT_INTERVAL
  Difficulty Adjustment Interval
• MAIN_CHAIN_ID
  Main chain id
• TARGET_SPACING
  Target Spacing: 10 minutes (600 seconds)
• UNROUNDED_MAX_TARGET
  Unrounded Maximum Target 0x00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

Traits

• WeightInfo
  Weight functions needed for btc_relay.