量子安全两方计算基础协议的理论研究

Elementary protocols in secure two-party computation, including bit commitment and oblivious transfer, are not only important research topics in cryptography but also fundamental building blocks for many complex cryptographic protocols. As their quantum versions, quantum bit commitment and quantum private query have also attracted a great deal of attention in quantum cryptography. However, compared with quantum key distribution (one of the most mature quantum techniques now), these quantum secure two-party computation protocols fall far behind in the researches of the security and especially the practicability. This situation cannot satisfy the application needs of quantum communication networks in anonymous authentication, electronic voting, private information retrieval and so on. This project studies several key problems in the elementary protocols of quantum secure two-party computation, including (1) designing a cheat-sensitive quantum bit commitment protocol which is not only loss-tolerant but also can resist the coherent attack, (2) designing a practical quantum private query protocol under the noisy channels, and (3) studying the new relationships between different cryptographic tasks in quantum cryptography and then using existing protocols to design quantum solutions for some new cryptographic tasks, including anonymous authentication. The research results are expected to improve the security and practicability of quantum secure two-party computation protocols, extend their application domain, and help to balance the development of different branches of quantum cryptography.

比特承诺和不经意传输等安全两方计算基础协议是密码学的重要研究课题，也是许多复杂密码协议的基础构件。作为其量子对应，量子比特承诺和量子保密查询在量子密码中也引起了广泛关注。但与量子密钥分配等当前最成熟的量子技术相比，这些量子安全两方计算协议在安全性和实用性方面的研究还存在很大差距，难以支撑量子通信网络在匿名认证、电子投票、私有信息检索等方面的应用需求。本项目探究解决量子安全两方计算基础协议中存在的几个关键问题，包括①设计既能容忍信道损失又能抵抗相干攻击的欺骗敏感量子比特承诺协议；②设计有噪信道下的量子保密查询方案；③挖掘各类密码任务在量子密码中的新型关系，进而借助已有方案设计匿名认证等密码任务的量子解决方案。预期研究成果将有助于提高量子安全两方计算协议的安全性、实用性，推广其应用领域，同时促进量子密码各分支均衡发展。

量子安全两方计算基础协议是密码学的重要研究课题。现有协议在实用性和安全性上还存在很多不足，难以支撑应用的需求。本项目组采用理论分析、算法分析、仿真等多种方法在量子安全两方及多方计算协议的设计、分析、实用性改进和安全性证明等方面进行了研究，先后在《IEEE Journal on Selected Areas in Communications》、 《Optics Express》、 《Physica A》、 《Quantum Information Processing》和《电子与信息学报》等期刊上发表论文12篇，其中SCI已收录10篇。.课题组主要研究进展如下：. (1)在有噪信道情形下设计量子保密查询协议，并给出该协议可容忍错误率的上界(如对10000比特的数据库，当要求错误率不超过0.01时，该上界为0.04)。.(2)研究了量子安全两方计算基础协议的应用推广，给出了借助量子不经意密钥传输实现匿名认证密钥交换的方法。 .(3)设计了一个高效的能够抵抗联合相干攻击的量子不经意传输方案。 .(4)研究了几类量子安全多方计算协议，针对这类协议在实用性方面的不足，给出了一个容失的无需量子存储的量子多方密钥协商协议、一个测量设备无关的量子三方密钥协商协议以及一个无需量子存储的量子合同签署协议。 .(5)对安全多方求和的通用量子协议、量子仲裁签名协议、量子动态秘密共享协议、量子多代理签名协议等量子多方安全计算协议进行密码分析，查找存在的安全漏洞，并给出改进的方法。.同时，进一步凝练了团队的研究方向，申请人入选洛阳市青年科技奖，培养青年骨干教师2名，顺利完成了研究目标和任务。