A survey on blockchain technology and its security

This paper offers a comprehensive overview of blockchain technology, tracing its evolution from its foundations in distributed ledger systems to its contemporary status as a cornerstone of decentralized infrastructure. The authors conduct a systematic review of the underlying architecture, consensus mechanisms, and the various security challenges inherent in public and private blockchain environments. By examining the structural vulnerabilities in network layers, transaction processing, and cryptographic implementations, the study provides a taxonomy of threats ranging from 51% attacks to smart contract exploitation. The methodology involves a rigorous categorization of consensus algorithms—such as Proof of Work, Proof of Stake, and Practical Byzantine Fault Tolerance—evaluating their security trade-offs against performance metrics like throughput and latency. The work serves as a foundational reference for understanding the inherent tension between decentralization, security, and scalability in modern blockchain implementations. It highlights the necessity of multi-layered defense strategies in securing distributed ecosystems against adversarial actors. Its significance lies in bridging the gap between theoretical blockchain properties and practical operational security requirements in evolving decentralized networks.