signature-replay-analysis

Detect and analyze signature replay vulnerabilities in smart contracts.

Updated Feb 25, 2026

Search Tags:#security audit #cryptography #smart contracts #vulnerability detection #EIP-712 #signature replay

Ready to run

npx skills add https://github.com/dajneem23/codex-skills --skill signature-replay-analysis-dajneem23

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: signature-replay-analysis
Source: https://github.com/dajneem23/codex-skills/tree/main/signature-replay-analysis
Command: npx skills add https://github.com/dajneem23/codex-skills --skill signature-replay-analysis-dajneem23

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill identifies and prevents vulnerabilities where cryptographic signatures can be reused or exploited across different chains, contracts, or timeframes, protecting against unauthorized actions.

Core Features & Use Cases

Replay Vulnerability Detection: Analyzes contracts for five types of signature replay attacks (same-chain, cross-chain, cross-contract, nonce-skip, expired-signature).
Secure Signature Verification: Provides guidance on implementing robust EIP-712 domain separators, nonce management, ecrecover safety, and deadline enforcement.
Use Case: When auditing a DeFi protocol that uses meta-transactions or permit functions, use this Skill to ensure that signatures cannot be replayed to drain funds or execute unintended actions.

Quick Start

Analyze the smart contract code for signature replay vulnerabilities and provide a detailed report.

Frequently Asked Questions about signature-replay-analysis

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

What is a signature replay attack in smart contracts?▼

A signature replay attack in smart contracts occurs when a cryptographic signature is reused across different chains, contracts, or timeframes to execute unauthorized actions, draining funds or bypassing intended access controls.

How do I detect cross-chain and cross-contract signature replay vulnerabilities?▼

Detect cross-chain and cross-contract signature replay vulnerabilities by thoroughly reviewing smart contract code for missing EIP-712 domain separators, improper nonce management, and ecrecover edge cases that allow signature reuse.

What's the best way to secure EIP-712 domain separators against replay attacks?▼

Secure EIP-712 domain separators against replay attacks by implementing robust chain-id verification, strict nonce management, and deadline enforcement to ensure signatures are invalid on unintended networks or contracts.

How do I audit permit and permit2 functions for signature replay risks?▼

Audit permit and permit2 functions for signature replay risks by verifying nonce-skip vulnerabilities, expired-signature enforcement, and ecrecover safety mechanisms to prevent unauthorized token approvals or fund drainage.

Does this signature replay analysis support ERC-1271 and meta-transaction security checks?▼

Yes, signature replay analysis supports ERC-1271 contract signature verification and meta-transaction security checks, ensuring that smart contract signature schemes prevent same-chain, cross-chain, and nonce-skip replay exploits.

Why does my ecrecover implementation allow signature replay across contracts?▼

Your ecrecover implementation may allow signature replay across contracts if it lacks proper domain separator binding, nonce tracking, or cross-contract message hashing, enabling identical signatures to authorize actions on multiple contracts.