广义多用户环境下多接收者加密方案的研究

项目名称： 广义多用户环境下多接收者加密方案的研究

项目编号： No.61502276

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 自动化技术、计算机技术

项目作者： 魏普文

作者单位： 山东大学

项目金额： 22万元

中文摘要： 现代网络环境逐渐呈现用户数量巨大、密码算法多样等特点，新环境下如何实现加密消息对海量用户的有效群发是关系云计算服务质量的重要问题。本项目从用户加密算法多样性角度研究多接收者加密方案在广义多用户环境下的安全性：构建合理的新型安全模型，刻画算法多样性对安全性的影响；降低归约损失对用户数量、密文数量及算法多样性的依赖，在标准假设下构造可兼容多种密码算法且具有紧安全性的新型多接收者加密方案，扩充多接收者加密的定义及应用范围；打破现有方案密文长度与接收者数量的线性关系瓶颈，在无可信第三方设置密钥的条件下，构造短密文长度的多接收者加密；首次采用可构造碰撞Universal Hash函数的新技术，探讨有状态加密技术与后向恢复技术在多接收者加密中的安全性及有效实现。本项目将为多接收者加密的构造与证明提供新方法，推动广义多用户环境下相关密码理论的研究，为云计算环境中海量用户的隐私保护问题提供有效解决方案。

中文关键词： 公钥加密方案；可证明安全性；多接收者加密；多用户环境

英文摘要： The huge number of users and the diversity of cryptographic algorithms have become emerging concerns in the modern network environments. How to efficiently send encrypted messages for multiple recipients in new environments is one of the critical security issues of cloud computing services. This project will study the security of multirecipient encryption schemes (MRES) when considering the diversity of users’ encryption algorithms: Construct a new security model in the generic multi-user setting in order to capture the security influenced by various users’ algorithms; Reduce the dependence of reduction loss on the number of users, the number of ciphertexts and the diversity of users’ algorithms and design tightly secure MRES which is compatible with different cryptographic algorithms under the standard assumptions; Refine the related definitions and expand the potential application range of MRES; Break the barrier of the linear relationship between the ciphertext length and the number of recipients in current multirecipient encryptions and construct short MRES without trusted third party setting up keys; Introduce a novel method on the construction of universal hash with collision accessibility and investigate the related security and efficiency problems when techniques of stateful encryptions and backward recovery applied in the design of MRES. This project will propose a completely new method for the construction and the security proof of multirecipient encryptions, promote the related research on the cryptography theory in multi-user setting and provide efficient solutions to the privacy problems in cloud computing.

英文关键词： public key cryptography;provable security ;multirecipient encryption;multi-user setting