Abstract: After the advent of quantum computers, the widely used public key cryptosystem will be broken, so it is urgent to propose new public key schemes to resistant quantum computing attacks. A single qubit-rotation transformation and classical one-way functions (Hash functions) are used to construct a multi-qubit quantum public key encryption scheme. The analysis results show that the new scheme is against the known forward search attack and a chosen ciphertext attack. Furthermore, the number of public key qubits used in the new scheme is obviously lower than that in the scheme presented by Kawachi et al.

Key words: multi-bit quantum public key encryption, chosen ciphertext attack, forward search attack