Detailed Instructions

Begin by explicitly defining the scope of the bridge solutions under review. Identify whether you are assessing a federated, sidechain, or trust-minimized bridge like a zk-rollup. The threat model must catalog all potential adversaries, including malicious validators, economic attackers, and protocol-level exploiters. Consider the assets at risk, such as wrapped BTC (wBTC) or Bitcoin-backed stablecoins.

• Sub-step 1: Asset & Chain Mapping: List all supported assets (e.g., wBTC, tBTC) and the destination chains (e.g., Ethereum, Solana).
• Sub-step 2: Adversary Specification: Document assumed adversary capabilities, such as controlling >33% of validator signatures or executing 51% attacks on the connected chain.
• Sub-step 3: Trust Assumptions: Enumerate all trusted entities, like multi-signature signers or oracle networks, and their required security deposits.

Tip: Use frameworks like STRIDE to systematically identify Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege threats.

Detailed Instructions

Scrutinize the cryptographic primitives and consensus mechanisms that secure the bridge's state and transactions. For bridges using multi-party computation (MPC) or threshold signatures, verify the key generation ceremony and the signature scheme (e.g., ECDSA, Schnorr). Assess the economic security of any bonded validator set and their slashing conditions for malicious behavior.

• Sub-step 1: Signature Verification: Check the bridge's on-chain verifier contract for correctness. For example, verify a Bitcoin SPV proof on Ethereum:

solidityCopy
function verifyBitcoinTx(
    bytes memory _proof,
    bytes32 _txHash,
    uint256 _blockHeight
) public view returns (bool) {
    // Implementation logic for SPV proof verification
}

• Sub-step 2: Validator Set Analysis: Examine the on-chain governance or staking contract (e.g., at address 0x1234...) to determine the minimum stake required and the penalty for double-signing.
• Sub-step 3: Upgrade Mechanisms: Review the timelock and multi-signature requirements for protocol upgrades to prevent unilateral changes.

Tip: Use tools like MythX or Slither to audit smart contract verifiers for common vulnerabilities.

Detailed Instructions

Evaluate the economic security model that deters malicious actions. Calculate the total value locked (TVL) versus the cost of attack, ensuring the slashable stake or insurance fund sufficiently covers potential losses. Analyze liveness guarantees by checking the bridge's ability to process withdrawals under adverse conditions, such as validator downtime or network congestion. Review the liquidity pools for wrapped assets to ensure they can handle large redemptions without significant slippage.

• Sub-step 1: TVL/Attack Cost Ratio: For a bridge with $500M TVL, verify the bonded stake is a significant percentage (e.g., >10% or $50M) to make attacks economically irrational.
• Sub-step 2: Withdrawal Delay Analysis: Measure the typical and maximum withdrawal delay periods. For example, a bridge might have a 24-hour challenge period for fraud proofs.
• Sub-step 3: Liquidity Provider Risk: Assess the centralization and collateralization of minting entities for wrapped assets like wBTC by checking their publicly attested reserves.

Tip: Monitor real-time metrics using blockchain explorers and DeFi dashboards to validate claimed TVL and liquidity depth.

Detailed Instructions

Conduct a thorough code audit of the bridge's core smart contracts and off-chain components. Verify that the implementation matches the specified protocol and contains no critical vulnerabilities. Review the operational security practices, including key management, node deployment, and monitoring systems for anomalous transactions. Examine the incident response plan and historical performance during past outages or exploits.

• Sub-step 1: Smart Contract Review: Use static analysis and manual review on the bridge's GitHub repository (e.g., repo/bridge-core/contracts/) to check for reentrancy, integer overflows, and access control issues.
• Sub-step 2: Node Configuration Check: Verify that validator nodes are run on geographically distributed, fault-tolerant infrastructure with commands like systemctl status bridge-node to ensure service health.
• Sub-step 3: Response Protocol Verification: Confirm the existence of a publicly documented emergency pause function, accessible via a multi-signature wallet (e.g., requiring 5-of-8 signatures), and test the procedure in a testnet environment.

Tip: Cross-reference audit reports from reputable firms like Trail of Bits or Quantstamp, but do not rely on them exclusively; conduct independent verification.

Detailed Instructions

Synthesize all assessment data into a standardized scoring matrix to enable objective comparison between different bridge solutions. Assign weighted scores to categories like cryptographic security, economic robustness, decentralization, and operational maturity. Calculate a final composite risk score for each bridge, highlighting critical trade-offs, such as higher security versus slower transaction finality. Document all assumptions and limitations of the assessment.

• Sub-step 1: Category Weighting: Assign percentage weights based on priority (e.g., Cryptographic Security: 40%, Economic Guarantees: 30%, Operational Review: 20%, Scope/Threat Model: 10%).
• Sub-step 2: Scoring Implementation: Use a simple script to compute scores. For example:

pythonCopy
def calculate_score(weights, ratings):
    # weights = {'crypto': 0.4, 'economic': 0.3, ...}
    # ratings = {'crypto': 85, 'economic': 70, ...}
    score = sum(weights[cat] * ratings[cat] for cat in weights)
    return score  # e.g., 78.5

• Sub-step 3: Risk Mitigation Summary: For each bridge, list the top 3 identified risks (e.g., "Centralized minting authority for wBTC") and recommended mitigations (e.g., "Switch to a over-collateralized, decentralized minting model").

Tip: Present results in a dashboard format, clearly distinguishing between audited theoretical security and observed on-chain historical performance.