Post‐Quantum Cryptosystems for Blockchain
K. Tamil Selvi, R. Thamilselvan · 2022
Blockchain with its inherent characteristics like transparency, accountability, and reliability finds its place in numerous applications. These characteristics are enabled through hash functions and public key cryptography. However, these hash functions and public key cryptography are non-resistance to quantum attacks. This leads to the rise of post-quantum cryptosystem for distributed ledger technologies like blockchain. The post-quantum cryptosystem can be modeled through public key post-quantum cryptosystems and post-quantum signing algorithms. Many variants of public key–based systems are code-based, multivariate-based, and lattice-based cryptosystems. Signing algorithms can be implemented as code-based or hash-based. Post-quantum blockchains are derived from quantum-resistant blockchain cryptography which are immune to Grover's and Shor's algorithm-based security attacks. Further secured blockchain transaction can be implemented using quantum key distribution (QKD) through secured key exchange. QKD can support one-time pad (OTP) generation, which is a large single key pre-shared between sender and receiver. This OTP can be generated using quantum random number generation. Hybrid post-cryptosystem that combines pre-quantum and post-quantum cryptosystem aims to protect the transactions of blockchain from quantum attacks. Although this system is secure, there is a complementation between security, resource consumption, and high complex of computation. The compression mechanisms can be employed to reduce the data transmission overhead. Thus, most relevant post-quantum blockchain system can be built based on applications requirements and security constraints.