Solidity Security Master smart contract security best practices, vulnerability prevention, and secure Solidity development patterns. When to Use This Skill - Writing secure smart contracts - Auditing existing contracts for vulnerabilities - Implementing secure DeFi protocols - Preventing reentrancy, overflow, and access control issues - Optimizing gas usage while maintaining security - Preparing contracts for professional audits - Understanding common attack vectors Critical Vulnerabilities 1. Reentrancy Attacker calls back into your contract before state is updated. Vulnerable Code: Secure P…