Blockchain Security: Vulnerabilities and Protective Measures

Blockchain technology offers a decentralized and tamper-resistant framework for secure transactions. However, its growing adoption across industries—from finance to supply chain management—has also exposed it to critical security vulnerabilities. Issues such as smart contract flaws, 51% attacks, and Sybil attacks can undermine the integrity of blockchain applications, resulting in financial losses and diminished trust. This paper reviews the current state of blockchain security by examining key vulnerabilities, their impacts, and existing protective measures. It proposes a comprehensive security framework that integrates formal verification methods, enhanced consensus mechanisms, and international collaboration to mitigate these risks. The feasibility of these measures is discussed with regard to computational overhead and scalability challenges. Through real-world case studies, the review underscores the urgency of robust, multi-layered defenses and calls for collaborative efforts among developers, researchers, and regulators.