Blockchain Challenges and Security Schemes: A Survey

This survey provides a detailed examination of the persistent security challenges facing blockchain systems, with a particular focus on the integration of security schemes to mitigate common attack vectors. The author investigates how blockchain architectures are susceptible to diverse threats including double-spending, selfish mining, and eclipse attacks, while also analyzing the effectiveness of existing mitigation strategies. The paper employs a comparative analysis of cryptographic techniques, highlighting the utility of formal verification and multi-signature schemes in hardening transaction integrity. Furthermore, the survey addresses the scalability-security dilemma, noting that while security enhancements often introduce latency, they are essential for the adoption of permissionless networks in enterprise environments. By aggregating contemporary research on attack patterns, the study offers a critical perspective on the maturity of current defensive infrastructures. It argues that while blockchain provides inherent tamper-resistance, the surrounding ecosystem remains fragile due to flawed implementation of smart contracts and user-facing infrastructure. The significance of this work is in its synthesis of defensive frameworks, serving as a roadmap for researchers aiming to improve the security lifecycle of blockchain deployments.