We present an implementation of Kuang and Bettenburg's Quantum Permutation Pad (QPP) used to encrypt superposition states. The project was conducted on currently available IBM quantum systems using the Qiskit development kit. This work extends previously reported implementation of QPP used to encrypt basis states and demonstrates that application of the QPP scheme is not limited to the encryption of basis states. For this implementation, a pad of 56 2-qubit Permutation matrices was used, providing 256 bits of entropy for the QPP algorithm. An image of a cat was used as the plaintext for this experiment. To create corresponding superposition states, we applied a novel operator defined in this paper. These superposition states were then encrypted using QPP, producing superposition ciphertext states. Due to the lack of a quantum channel, we omitted the transmission and executed the decryption procedure on the same IBM quantum system. If a quantum channel existed, the superposition ciphertext states could be transmitted as qubits, and be directly decrypted on a different quantum system. We provide a brief discussion of the security, although the focus of the paper remains on the implementation. Previously we have demonstrated QPP operating in both classical and quantum computers, offering an interesting opportunity to bridge the security gap between classical and quantum systems. This work broadens the applicability of QPP for the encryption of basis states as well as superposition states.

翻译：本文展示了Kuang和Bettenburg提出的量子置换垫（QPP）在加密叠加态中的实现方法。该实验在现役IBM量子系统上使用Qiskit开发工具包完成。本研究扩展了此前QPP加密基态的实施方案，证明QPP方案的应用并不局限于基态加密。实现过程中使用了56个2量子比特置换矩阵构成的置换垫，为QPP算法提供256比特熵。实验以一张猫的图像作为明文，通过本文定义的新型算子生成相应的叠加态，随后利用QPP加密这些叠加态产生叠加密文态。由于缺乏量子信道，我们省略了传输环节，在同一IBM量子系统上执行解密流程。若存在量子信道，叠加密文态可作为量子比特传输，并在不同量子系统上直接解密。虽然本文重点在于实现方法，仍对安全性进行了简要讨论。我们此前已证明QPP在经典计算机与量子计算机上均可运行，为弥合经典系统与量子系统间的安全鸿沟提供了独特机遇。本工作拓展了QPP对基态及叠加态加密的适用范围。