Electronic voting (e-voting) is an electronic means for casting and counting votes. It is an efficient and cost-effective way for conducting a voting procedure, which has characteristic of being magnanimous data and real time and requesting high safety. However, concerns on security of networking and privacy of communication for e-voting have been grown. Securing e-voting is very urgent and has becoming a popular topic in the area of communications and networking. We present techniques to exploit blockchain in P2P network to improve the security of e-voting. First, we design a synchronized model of voting records based on distributed ledger technology (DLT) to avoid forgery of votes. Second, we design a user credential model based on elliptic curve cryptography (ECC) to provide authentication and non-repudiation. Third, we design a withdrawal model that allows voters to change their vote before a preset deadline. By integrating the above designs, a blockchain-based e-voting scheme in P2P network is proposed for essential requirements of e-voting process. To prove and verify the scheme, a blockchain-based e-voting system for multiple candidates has been designed on Linux platforms in P2P network. The system involves electronic voting theory, cryptography, and software engineering theory. The implementation result shows that it is a practical and secure e-voting system, which solves the problem on forgery of votes during e-voting. The blockchain-based e-voting system can be applied to a variety of networking applications directly.

With the advancement of the application of Internet of Things (IoTs), the IoT technology is combining with the social network, forming a new network with private object information as the media and social entertainment as the purpose. Social Internet of things (SIoTs) is a new application of IoT technology in social network. The current SIoT systems are centralized and the user's security and privacy is not properly protected. In order to address the challenges in SIoTs, we propose a privacy protection system for the users. First, we propose a post-quantum ring signature. Second, we propose a blockchain system based on the ring signature. Compared with the traditional SIoTs, our system is based on post-quantum techniques, which is secure against both traditional computers and quantum computers. The results of the blockchain system show that it is very suitable for SIoTs.

As digital transformation progresses across industries, digital twins have emerged as an important technology. In healthcare, digital twins are created by digitizing patient parameters, medical records, and treatment plans to enable personalized care, assist diagnosis, and improve planning. Data is core to digital twins, originating from physical and virtual entities as well as services. Once processed and integrated, data drives various components. Medical records are critical healthcare data but present unique challenges for digital twins. However, directly storing or encrypting medical records has issues. Plaintext risks privacy leaks while encryption hinders retrieval. To address this, we present a cloud-based solution combining post-quantum searchable encryption. Our system includes key generation using Physical Unable Functions (PUF). It encrypts medical records in cloud storage, verifies records using blockchain, and retrieves records via cloud. By integrating cloud encryption, blockchain verification and cloud retrieval, we propose a secure and efficient cloud-based medical records system for digital twins. Our implementation demonstrates the system provides users efficient and secure medical record services, compared to related designs. This highlights digital twins’ potential to transform healthcare through secure data-driven personalized care, diagnosis and planning.