Fifth generation (5G) networks are the base communication technology for connecting objects in the internet of things (IoT) environment. 5G is being developed to provide extremely large capacity, robust integrity, high bandwidth, and low latency. With the development and innovating new techniques for 5G-IoT, it surely will drive to new enormous security and privacy challenges. Consequently, secure techniques for data transmissions will be needed as the basis for 5G-IoT technology to address these arising challenges. Therefore, various traditional security mechanisms are provided for 5G-IoT technologies and most of them are based on mathematical models. With the growth and development of quantum technologies, traditional cryptographic techniques may be compromised due to their mathematical computation based construction. Quantum walks (QWs) is a universal model of quantum computation, which possesses inherent cryptographic features that can be utilized to build efficient cryptographic mechanisms. In this paper, we utilize the features of quantum walks to construct a new S-box method which plays a significant role in block cipher techniques for 5G-IoT technologies. As an application of the presented S-box mechanism and controlled alternate quantum walks (CAQWs) for 5G-IoT technologies a new robust video encryption mechanism is proposed. As well as to fulfill needs of encryption for varied files in 5G-IoT, we utilize the features of quantum walks to design a novel encryption technique for secure transmission of sensitive files in 5G-IoT paradigm. The analyses and results of the proposed cryptosystems show that it has better security properties and efficacy in terms of cryptographic performance.

The advent of quantum computing threatens blockchain protocols and networks because they utilize non-quantum resistant cryptographic algorithms. When quantum computers become robust enough to run Shor’s algorithm on a large scale, the most used asymmetric algorithms, utilized for digital signatures and message encryption, such as RSA, (EC)DSA, and (EC)DH, will be no longer secure. Quantum computers will be able to break them within a short period of time. Similarly, Grover’s algorithm concedes a quadratic advantage for mining blocks in certain consensus protocols such as proof of work. Today, there are hundreds of billions of dollars denominated in cryptocurrencies and other digital assets that rely on blockchain ledgers as well as thousands of blockchain-based applications storing value in blockchain networks. Cryptocurrencies and blockchain-based applications require solutions that guarantee quantum resistance in order to preserve the integrity of data and assets in these public and immutable ledgers. The quantum threat and some potential solutions are well understood and presented in the literature. However, most proposals are theoretical, require large QKD networks, or propose new quantum-resistant blockchain networks to be built from scratch. Our work, which is presented in this paper, is pioneer in proposing an end-to-end framework for post-quantum blockchain networks that can be applied to existing blockchain to achieve quantum-resistance. We have developed an open-source implementation in an Ethereum-based (i.e., EVM compatible) network that can be extended to other existing blockchains. For the implementation we have (i) used quantum entropy to generate post-quantum key pairs, (ii) established post-quantum TLS connections and X.509 certificates to secure the exchange of information between blockchain nodes over the internet without needing a large QKD network, (iii) introduced a post-quantum second signature in transactions using Falcon-512 post-quantum keys, and (iv) developed the first on-chain verification of post-quantum signatures using three different mechanisms that are compared and analyzed: Solidity smart-contracts run by the validators for each transaction, modified EVM Opcode, and precompiled smart contracts.