A survey on security and privacy issues of blockchain technology

Blockchain is gaining traction and can be termed as one of the furthermost prevalent topics nowadays. Although critics question about its scalability, security, and sustainability, it has already transformed many individuals' lifestyle in some areas due to its inordinate influence on industries and businesses. Granting that the features of blockchain technology guarantee more reliable and expedient services, it is important to consider the security and privacy issues and challenges behind the innovative technology. The spectrum of blockchain applications range from financial, healthcare, automobile, risk management, Internet of things (IoT) to public and social services. Several studies focus on utilizing the blockchain data structure in various applications. However, a comprehensive survey on technical and applications perspective has not yet been accomplished. In this paper, we try to conduct a comprehensive survey on the blockchain technology by discussing its structure to different consensus algorithms as well as the challenges and opportunities from the prospective of security and privacy of data in blockchains. Furthermore, we delve into future trends the blockchain technology can adapt in the years to come. Index Terms- Blockchains, Future Trends of Blockchains, Security, Privacy