Security and a decentralized system are identical unique features of Blockchain. In recent times, blockchain-based cryptocurrency has become mainstream, but the growth and value of transactions and application services remain volatile. Among all these applications, finding a fast consensus in a large-scale blockchain network frequently requires extreme energy for huge computations and storing the complete blockchain for verification. These problems prevent further commercialization. Here, we present a solution to this problem. In this paper, we introduce a revised blockchain consensus algorithm, PDPoS, to address the scalability and transaction efficiency limitations. The symmetry in between Proof of Stake (PoS) and Delegated Proof of Stake (DPoS) is PoS. However, their ways of working are dissimilar. Here, we review the existing consensus algorithms, such as Proof of work (PoW), PoS and DPoS, as they are directly relating to our proposed work: PDPoS. We highligh Delegated Proof of Stake (DPoS)–based crypto-currencies, as they have much higher transactions per second (TPS) than PoW-based currencies. Then, we describe our proposed works and the working steps of the proposed PDPoS. Simulation results of the proposed PDPoS with two layers result in improved efficiency. We used TPS as the evolution criteria for showing that the proposed PDPoS is more efficient than DPoS. This makes the proposed work more relevant to the large-scale blockchain network as it is more efficient and requires less energy consumption.

The Internet of Medical Things (IoMT) global market has grown and developed significantly in recent years, and the number of IoMT devices is increasing every year. IoMT systems are now very popular and have become part of our everyday life. However, such systems should be properly protected to preventing unauthorized access to the devices. One of the most popular security methods that additionally relies on real-time communication is Blockchain. Moreover, such a technique can be supported by the Trusted Third Party (TTP), which guarantees data immutability and transparency. The research and industrial community has predicted the proliferation of Blockchain-based IoMT (BIoMT), for providing security, privacy, and effective insurance processing. A connected environment comprises some of the unique features of the IoMT in the form of sensors and devices that capture and measure, recognize and classify, assess risk, notify, make conclusions, and take action. Distributed communication is also unique due to the combination of the fact that the Blockchain cannot be tampered with and the Peer-to-Peer (P2P) technique, especially compared to the traditional cloud-based techniques where the reliance of IoMT systems on the centralized cloud makes it somewhat vulnerable. This paper proposes a Blockchain-based technique oriented on IoMT applications with a focus on maintaining Confidentiality, Integrity, and Availability (the CIA triad) of data communication in the system. The proposed solution is oriented toward trusted and secure real-time communication. The presented method is illustrated by an example of a cloud-based hospital application. Finally, the security aspects of the proposed approach are studied and analyzed in detail.

Blockchain-based cyber-physical systems (CPSs) and the blockchain Internet of things (BIoT) are two major focuses of the modern technological revolution....

For virtual private network and LAN-to-LAN tunnel sessions, End-to-End security is the main constraint in private messaging scenarios. Internet Protocol Security can negotiate new keys for every communication, but when the key is compromised, it is a problem. Perfect Forward Secrecy is the resolution. In addition, the messaging scheme should be efficient and lightweight for keeping parity with daily needs. The popular Rivest-Shamir-Adleman (RSA) cipher is omnipresent in secure communications but has many scientific problems. So here, in this paper, a lightweight and efficient Secure Hybrid RSA (SHRSA) messaging scheme with four-layered authentication stack is implemented and analyzed. The scheme is resolving the problem of asymptotic very low speed of decryption of RSA, the computational modular exponentiation complexity and partial key exposure vulnerability issues of RSA, and many more. The four-layered authentication stack have eliminated the need of the use of any password, external digital certificates, and a third party for authentication with its own four techniques in a staked way. We have found that in evolutions and analysis of the scheme, it is not only resolving various scientific problems of RSA but also occupying 2%-4% less CPU than main RSA and occupying 1%-3% less memory than main RSA. Its decryption average time has gained 8.858 times compared to the main RSA and gained 2.248 times compared to CRT RSA. We have found that the RSA, CRT-RSA, and SHRSA's encryption throughput are alike-all are around 6 KB/Sec but decryption throughput of SHRSA has gained 8.5345 times than main RSA and gained 2.1174 times than CRT-RSA. The results obtained have shown us the relevancies of the SHRSA messaging scheme to be integratable as a cipher in Blockchain architectures, cyber-physical systems, and the Internet of Everything.