密钥隔离密码体制及其应用研究

发布时间：2018-12-18 18:04

【摘要】：近年来信息技术的发展速度惊人,随之带来的信息安全问题也日趋显著。随着人们对隐私保护和数据安全的重视程度逐渐加深,密码技术的应用变得愈加广泛。在一个密码系统中,用户可能会频繁地使用密钥进行加解密等操作,这就有一定概率会发生密钥泄漏问题。该问题在一般的密码系统中是不可避免的。密钥隔离密码体制则是用于抵抗密钥泄漏问题的有效方法之一。在密钥隔离密码系统中,系统生命周期被划分为N个有序的时间片,在整个系统生命周期中,用户私钥随着时间片的更替而不断更新,但用户的公钥仍保持不变。为保证用户私钥更新的安全性,每个用户都会配备一个独一无二的物理绝对安全但计算能力较弱的设备,即协助者,用户必须通过与其绑定的协助者进行交互才能完成私钥更新。本文通过对密钥隔离相关方案进行深入研究,分析了密钥隔离加密技术的设计机理和设计思想,并结合代理重加密体制和基于无证书的加密体制提出了两个具体的密钥隔离加密方案。本文在研究过程中主要取得了以下研究成果:1.本文对密钥隔离密码体制的研究现状进行了探讨并对其内在设计机理进行了分析。本文对密钥隔离密码体制的形式化定义进行了描述,并对其安全模型和安全属性进行了归纳整理。然后详细分析了典型的密钥隔离加密方案,并对其内在设计机理和设计思想进行了阐释。2.本文结合代理重加密体制的特性,提出一个具有密钥隔离的代理重加密方案。目前为止,虽已有不少代理重加密方案被提出,但代理重加密体制中存在的密钥泄漏问题未得到解决。本文将密钥隔离密码体制和代理重加密体制相结合,提出了一个云数据共享环境下具有密钥隔离的代理重加密方案,并对其系统模型、安全性和效率进行了分析。3.本文提出了一个多协助者的基于无证书的密钥隔离加密方案。通过在密钥隔离加密体制中引入无证书和多协助者的概念,该方案不仅避免了证书管理问题和密钥托管问题,而且较一般的密钥隔离加密方案,进一步降低了协助者发生密钥泄漏的危害性,具有更强的密钥隔离能力。此外,本文还利用可证明安全理论对所提方案进行了安全性分析,并与已有相关方案进行了性能对比。
[Abstract]:With the rapid development of information technology in recent years, the problem of information security is becoming more and more obvious. With the increasing attention to privacy protection and data security, cryptography has become more and more widely used. In a cryptographic system, the user may frequently use the key to encrypt and decrypt, so there is a certain probability that the key leakage will occur. This problem is inevitable in general cryptosystem. Key isolation cryptosystem is one of the effective methods to resist key leakage. In the key isolation cryptosystem, the system life cycle is divided into N ordered time slices. In the whole system life cycle, the private key of the user is updated with the change of the time slice, but the public key of the user remains unchanged. To ensure the security of the user's private key update, each user is provided with a unique device that is physically absolutely secure but less computationally powerful, namely, the helper, Users must interact with their bound facilitators to complete private key updates. In this paper, the design mechanism and design idea of key isolation encryption technology are analyzed through in-depth research on key isolation schemes. Combined with proxy reencryption and certificate-free encryption, two key isolation schemes are proposed. In this paper, the main research results are as follows: 1. In this paper, the research status of key isolation cryptosystem is discussed and its internal design mechanism is analyzed. In this paper, the formal definition of key isolation cryptosystem is described, and its security model and security attributes are summarized and sorted out. Then the typical key isolation encryption scheme is analyzed in detail, and its internal design mechanism and design idea are explained. 2. This paper presents a proxy reencryption scheme with key isolation combined with the characteristics of proxy reencryption system. So far, although many proxy reencryption schemes have been proposed, the key leakage problem in proxy reencryption system has not been solved. In this paper, we combine key isolation cryptosystem with proxy reencryption system, propose a proxy reencryption scheme with key isolation in cloud data sharing environment, and analyze its system model, security and efficiency. In this paper, a multi-aider-based key isolation encryption scheme without certificates is proposed. By introducing the concepts of non-certificate and multi-helper in key isolation encryption system, the scheme not only avoids the problem of certificate management and key escrow, but also the general key isolation encryption scheme. It further reduces the harm of key leakage and has stronger ability of key isolation. In addition, the security of the proposed scheme is analyzed by using the provable security theory, and the performance of the proposed scheme is compared with that of the existing schemes.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN918.4

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