格上匿名广播加密体制的研究

With the advent of the quantum cryptography era, how to design broadcast encryption schemes against quantum attacks has become a focus of research. In this project, we will design a series of corresponding broadcast encryption schemes, which are based on LWE of Lattice, to protect both data confidentiality and identity anonymity. The research content of this project mainly includes:(1)we construct a generic anonymous identity-based broadcast encryption scheme from lattice by combining an anonymous identity-based encryption scheme from lattice and an anonymous tag-based hint system; the scheme is chosen-ciphertext security in the standard model and supports efficient decryption.(2)we extend the congruence public key cryptosystem to a multi-user setting by employing the Chinese Remainder Theorem and construct a series of anonymous identity-based broadcast encryption schemes by using lattice basis delegation in fixed dimension. Our schemes obtain chosen-plaintext security in the standard model and have several attractive properties, such as fixed-length public key, private key and ciphertext and fixed encryption/decryption operation overhead. (3)we propose an anonymous identity-based broadcast encryption system with traitor tractability from lattice by leveraging the Chinese Remainder Theorem and an open black box tracking method. The system can effectively achieve dynamic expansion and stateless reception for client devices. Also, it has the practical performance in terms of storage, computing/communication overhead, and functions.

量子密码时代的到来，如何设计能抵抗量子攻击的广播加密方案成为研究的热点。本项目拟基于格上带错误学习困难(LWE)问题，设计出相应的基于格密码的广播加密方案，确保数据的保密性和用户身份的匿名性。本项目主要研究内容包括：(1) 结合格上匿名身份基加密和匿名标签基提示法，构造出格上通用的匿名身份基广播加密方案，确保用户解密高效，并且在标准模型下证明方案能抵抗选择密文攻击。(2) 基于中国剩余定理，将格上同余公钥加密系统扩展到多用户环境，结合维数不变的格基代理技术，构造出具有定长公私钥、定长密文、固定加/解密运算开销等良好性质的格上匿名身份基广播加密方案，并在标准模型下证明方案能抵抗选择明文攻击。(3) 基于中国剩余定理和公开黑盒追踪方法，构建格上具有叛逆者追踪功能的匿名身份基广播加密系统，使得系统能够有效实现用户端的动态扩展和无状态接收功能，并使其在存储、计算/通信开销及功能等方面满足工业需求。

量子密码时代的到来，如何设计能抵抗量子攻击的广播加密方案成为研究的热点。本项目拟基于格上带错误学习困难(LWE)问题，设计出相应的基于格密码的广播加密方案，确保数据的保密性和用户身份的匿名性。本项目主要研究内容包括：(1) 结合格上匿名身份基加密和匿名标签基提示法，构造出格上通用的匿名身份基广播加密方案，确保用户解密高效，并且在标准模型下证明方案能抵抗选择密文攻击。(2) 基于中国剩余定理，将格上同余公钥加密系统扩展到多用户环境，结合维数不变的格基代理技术，构造出具有定长公私钥、定长密文、固定加/解密运算开销等良好性质的格上匿名身份基广播加密方案，并在标准模型下证明方案能抵抗选择明文攻击。(3) 基于中国剩余定理和公开黑盒追踪方法，构建格上具有叛逆者追踪功能的匿名身份基广播加密系统，使得系统能够有效实现用户端的动态扩展和无状态接收功能，并使其在存储、计算/通信开销及功能等方面满足工业需求。