Nonce Reuse Risk Explainer

WHAT IT DOES

Nonce Reuse Risk Explainer is a read-only tool that analyzes transactions to detect nonce reuse vulnerabilities and generates AI-powered plain-language explanations of reuse risks. It reads transaction nonce, sender address, transaction history, signature values (v, r, s), chain ID, transaction hash, pending transaction queue, used nonces for an address, account state, transaction order, recent transactions, signature reuse patterns, and duplicate transaction detection. The tool then presents this data alongside an AI-generated explanation of whether a transaction is reusing a nonce, the risks of nonce reuse (including transaction replays and accidental overwrites), and recommended safe practices — helping you avoid costly mistakes before signing and broadcasting a transaction.

HOW TO USE

Connect your wallet using the BGWallet bridge and select your target network. Enter the transaction hash you want to analyze. Optionally enter the sender address (auto-detected from the transaction). Click "Analyze nonce reuse" to read on-chain data. The tool displays the transaction hash, sender address, nonce, nonce reuse status (Safe or Reused), and used nonces count. A prominent warning banner appears if a reuse is detected. Detailed information includes chain ID, transaction hash, signature values (v, r, s), account state, transaction order, reuse pattern, and duplicate detection. A recommendation box provides specific safe practices. An AI explanation appears below the on-chain data, detecting whether the transaction is reusing a nonce, explaining the risks of nonce reuse (including transaction replays and accidental overwrites), and recommending safe practices before you sign and broadcast a transaction. The wallet's own signature step still protects you — this explanation is informational only and does not replace reviewing what you approve in your wallet.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 with the provider from the BGWallet bridge to read on-chain transaction data. No hardcoded contract addresses are used — you are always in control of which contract you trust. When analyzing nonce reuse, the tool reads the transaction nonce from the transaction object, reads the sender address from the transaction's from field, reads the transaction history for the sender address via provider.getTransactionCount(address) and by scanning previous transactions, reads the signature values (v, r, s) from the transaction object, reads the chain ID from the network, reads the transaction hash from the user input, reads the pending transaction queue via provider.getPendingTransactions() (if available), tracks used nonces for the address by scanning the transaction history, reads the account state via provider.getTransactionCount(address), reads the transaction order by comparing nonce values, reads recent transactions via the transaction history scan, detects signature reuse patterns by comparing signature values across transactions, and detects duplicate transactions by comparing transaction hashes and nonces. The tool fetches event logs by walking backwards in chunks and halving chunk size on failure, ensuring logs are properly read despite varying RPC limitations. The data is formatted and passed to the AI bridge via BGAI.generate() with a structured prompt that includes all the on-chain data read. The AI is instructed to detect whether the transaction is reusing a nonce, explain the risks of nonce reuse (including transaction replays and accidental overwrites), and recommend safe practices — while stating plainly that it cannot detect nonce reuse across different wallets sharing the same key, cannot detect nonce reuse in transactions that have been replaced if they are not in the tx pool, and cannot guarantee that a nonce is safe to reuse even if no reuse is detected. The AI response is capped at 1,024 tokens to ensure concise, focused nonce risk assessments. All computed values are guarded against negative numbers — if a nonce or transaction count appears invalid, the tool flags it rather than displaying nonsensical values.

WHAT IT CANNOT SEE

This tool cannot detect nonce reuse across different wallets sharing the same key. It cannot detect nonce reuse in transactions that have been replaced (same nonce, higher gas) if they are not in the tx pool. It cannot detect intentional nonce reuse in off-chain signature systems. It cannot guarantee that a nonce is safe to reuse even if no reuse is detected. The AI explanation is generated from on-chain data only and cannot detect off-chain nonce management, wallet implementation details, or nonce reuse in replaced transactions not visible in the tx pool. It cannot predict whether a nonce reuse will cause a transaction to be overwritten or replayed. The tool does not continuously monitor nonce usage; each analysis is a snapshot at the time of the lookup. It cannot detect pending nonce replacements, stale transaction pools, or off-chain nonce reuse. The tool does not store any data persistently; all state is in-memory and resets on reload. The AI explanation is informational and does not constitute financial advice, legal advice, or a guarantee of transaction safety or nonce correctness.

PLEASE NOTE

Nonce Reuse Risk Explainer works exclusively with EVM-compatible chains. It requires a Web3 wallet (MetaMask or similar) and the BGWallet bridge. Explanations are AI-generated from data the app reads on-chain — always review what you are actually signing in your wallet before approving it. Nonce reuse carries significant risk including transaction replay attacks, accidental overwrites of pending transactions, and potential loss of funds. Use this tool as a guide only; always cross-check with wallet transaction history and independent sources for critical decisions. This is experimental software; use at your own risk.