Here we introduce an improved approach to Variational Quantum Attack Algorithms (VQAA) on crytographic protocols. Our methods provide robust quantum attacks to well-known cryptographic algorithms, more efficiently and with remarkably fewer qubits than previous approaches. We implement simulations of our attacks for symmetric-key protocols such as S-DES, S-AES and Blowfish. For instance, we show how our attack allows a classical simulation of a small 8-qubit quantum computer to find the secret key of one 32-bit Blowfish instance with 24 times fewer number of iterations than a brute-force attack. Our work also shows improvements in attack success rates for lightweight ciphers such as S-DES and S-AES. Further applications beyond symmetric-key cryptography are also discussed, including asymmetric-key protocols and hash functions. In addition, we also comment on potential future improvements of our methods. Our results bring one step closer assessing the vulnerability of large-size classical cryptographic protocols with Noisy Intermediate-Scale Quantum (NISQ) devices, and set the stage for future research in quantum cybersecurity.

翻译：本文介绍了一种针对密码协议的改进型变分量子攻击算法（VQAA）。相较于先前方法，我们的方法能以更高效率和显著更少的量子比特对知名密码算法实施稳健的量子攻击。我们针对S-DES、S-AES和Blowfish等对称密钥协议实现了攻击仿真。例如，我们展示了如何通过8量子比特小型量子计算机的经典仿真，以比暴力攻击少24倍的迭代次数破解32位Blowfish实例的密钥。我们的研究还表明，针对S-DES和S-AES等轻量级密码算法的攻击成功率有所提升。同时探讨了对称密钥密码学之外的应用前景，包括非对称密钥协议和哈希函数。此外，我们还对本方法的未来改进方向进行了展望。本研究结果使得利用噪声中等规模量子（NISQ）设备评估大型经典密码协议的脆弱性更近一步，并为量子网络安全领域的未来研究奠定了基础。