基于属性基加密的细粒度访问控制机制研究

发布时间：2019-07-09 21:13

【摘要】：数据外包能减少数据所有者的成本。然而,当数据被存储在远程服务器上时,数据所有者会丧失对其敏感数据的控制,不可信方可能访问这些敏感数据。传统的方法使用完全可信的服务器来存储和负责对敏感数据的访问控制,如果用户拥有某些证书,满足访问控制策略,他便可以访问敏感数据。然而,一旦存储敏感数据的服务器受到威胁,数据的机密性也会受到威胁。因此,对服务器中存储的敏感数据需要以加密形式存储,使得即使服务器受到威胁,数据的机密性也得以保证。然而,传统的加密方法存在如下缺点:(1).加密是一个用户和另一个用户秘密地共享数据的方式;(2).对加密数据的访问是要么全访问,要么全不访问。也就是说,它们不能用来处理对加密数据的富有表达力的访问控制。在许多应用中,比如云存储系统中,数据所有者可能希望根据对接收者属性的策略来选择性地共享敏感数据。不是每次为各方加密数据,而是一次为所有各方加密数据。近年来提出的属性基加密方案能很好地满足这些需求。属性基加密是一种新颖的公钥加密范例,它允许用户基于属性加密和解密消息,而且它富有表达力,能对加密数据实施细粒度的访问控制。本文进行了基于属性基加密的细粒度访问控制机制研究,其主要研究内容和创新点包括:1.提出了黑盒可追责密文策略属性基加密方案既存的属性基加密方案需要一个可信的中央机构。此中央机构拥有方案的主秘密,能计算与用户的任意属性相关的私钥,并能解密对任意用户加密的任意密文,生成和分发与属性相关的私钥给其他用户。因此,它必须是绝对可信的。如果中央机构从事恶意活动,它将不会被抓住和起诉。也就是说,属性基加密方案中仍然存在密钥托管问题。如果这个问题没被解决,将会影响属性基加密方案的采纳。本文提出了黑盒可追责密文策略属性基加密方案,在这个方案中,一个安全的私钥生成协议被构造,法官能判断译码盒是由恶意的用户创建还是由恶意的中央机构创建。本文方案减轻了对中央机构的信任,使得中央机构被指控滥用这种信任的可能性被减少,从而使得属性基加密方案能很好地对加密数据实施细粒度的访问控制。2.提出了密文策略属性基代理重加密方案在属性基加密方案中,用户的私钥与属性集相关,敏感数据在对属性的访问结构下被加密成密文,当且仅当其属性满足与密文相关的访问结构的用户才能解密密文。然而,在加密数据不被解密的前提下,既存的属性基加密方案并不支持对属性基加密方案中访问结构的更新。本文提出了密文策略属性基代理重加密方案,它允许在不解密密文的前提下,通过一个诚实而又好奇的代理如云服务器转换与初始密文相关的访问结构,此代理在另一个访问结构下重加密最初的密文成重加密密文,使得其属性满足新访问结构的用户能解密重加密的密文。所提方案较好地解决了在采用属性基加密方案对加密数据实施细粒度访问控制时,属性基加密方案中访问结构频繁地发生变化的问题。3.提出了基于属性基加密的具有细粒度访问控制的不经意传输方案在外包系统中,尽管加密技术被用来保护外包数据,但对像谁访问了外包数据以及他怎样访问这些数据的这类型的敏感数据,服务提供商仍能收集它们。为了保护用户的隐私和让服务提供商实施访问控制,本文提出了基于属性基加密的具有细粒度访问控制的不经意传输方案,其中,数据库服务器中的数据用访问控制策略来保护,仅有其证书满足访问策略的用户才能访问这些数据,而服务提供商不会了解到用户访问了哪些数据或用户的证书。本文方案具有如下优势:第一、本文方案维护了不经意传输的隐私特性,提供了细粒度的访问控制机制。第二、它允许直接支持AND门,OR门和Threshold的富有表达力的访问控制策略。第三、在本文方案中的通信复杂度与用户访问的记录数成常量关系。第四、本文方案在素数阶环境下被构造。4.提出了具有外包解密功能的基于素数阶群的内积谓词加密方案在谓词加密方案——属性隐藏的属性基加密方案中,密文既隐藏明文消息,又隐藏属性。谓词加密对加密数据实施细粒度的访问控制和对加密数据进行搜索。然而,谓词加密在效率上存在的主要缺点是密文的大小和解密它的时间会随着谓词的复杂性而增长。本文提出了具有外包解密功能的基于素数阶群的内积谓词加密方案,它大大地减少了用户的开销。在该方案中,用户提供给云服务器一把转换密钥,以允许云服务器转换密文属性满足谓词的谓词加密密文成一条简短的密文,从而大大减少用户解密密文的时间,而云服务器也不会了解任意的用户消息,同时,用户能对云服务器进行的转换进行验证,以保证转换的正确性。
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[Abstract]:The out-of-data package can reduce the cost of the data owner. However, when data is stored on a remote server, the data owner loses control over its sensitive data, and the untrusted party may access the sensitive data. The traditional approach uses a fully trusted server to store and take charge of access control for sensitive data, and if the user has certain credentials to meet the access control policy, he can access sensitive data. However, once the server that stores sensitive data is threatened, the confidentiality of the data is also compromised. Therefore, sensitive data stored in the server needs to be stored in encrypted form, so that the confidentiality of the data is guaranteed even if the server is threatened. However, the conventional encryption method has the following disadvantages: (1). Encryption is the way a user and another user share data in secret; (2). Access to the encrypted data is either full access or full access. That is, they cannot be used to handle access control for the rich expression of the encrypted data. In many application, such as a cloud storage system, a data owner may wish to selectively share sensitive data in accordance with a policy of that recipient's attributes. It is not to encrypt data for each party at a time, but to encrypt data for all parties at a time. The attribute-based encryption scheme proposed in recent years can well meet these demands. Attribute-based encryption is a novel public-key encryption paradigm that allows users to encrypt and decrypt messages based on attributes, and it is rich in expression, enabling fine-grained access control to encrypted data. In this paper, a fine-grained access control mechanism based on attribute-based encryption is studied, and the main research contents and innovation points are as follows:1. It is proposed that the property-based encryption scheme of the property-based encryption scheme of the cryptograph policy of the black box can be traced back to the existing property-based encryption scheme requires a trusted central mechanism. The central mechanism has the master secret of the scheme, can calculate the private key related to any attribute of the user, and can decrypt any cipher text encrypted by any user, and generate and distribute the private key related to the attribute to other users. It must therefore be absolutely credible. If the central authority is engaged in a malicious activity, it will not be caught and prosecuted. That is, a key escrow problem is still present in the attribute-based encryption scheme. If this problem is not resolved, the adoption of the attribute-based encryption scheme will be affected. In this paper, a key encryption scheme is proposed in this paper. In this scheme, a secure private key generation protocol is constructed, and the judge can judge whether the decoding box is created by a malicious user or by a malicious central mechanism. The scheme reduces the trust of the central authorities, so that the possibility of the central authorities being charged with the abuse of such trust is reduced, so that the attribute-based encryption scheme can well implement fine-grained access control to the encrypted data. In the attribute-based encryption scheme, the key of the user's private key is related to the attribute set, and the sensitive data is encrypted into the cipher text under the access structure of the attribute, and the cipher text can be decrypted only when the attribute of the attribute satisfies the user of the access structure related to the cipher text. However, if the encrypted data is not decrypted, the existing attribute-based encryption scheme does not support the update of the access structure in the attribute-based encryption scheme. This paper presents a scheme for re-encryption of the attribute-based proxy of the cipher-text strategy, which allows the access structure related to the initial cipher text to be converted by an honest and curious agent, such as the cloud server, without the decryption of the cipher text, The agent re-encrypts the original cipher text to re-encrypt the cipher text under the other access structure, so that the user whose property satisfies the new access structure can decrypt the re-encrypted cipher text. The proposed scheme better solves the problem that the access structure in the attribute-based encryption scheme is changed frequently when the attribute-based encryption scheme is adopted to implement fine-grained access control to the encrypted data. in an out-of-packet system, an inadvertent transmission scheme with fine-grained access control based on an attribute-based encryption is proposed, although encryption techniques are used to protect the outsourced data, Service providers can still collect them. in order to protect the privacy of the user and to let the service provider implement the access control, the paper proposes an unintentional transmission scheme with fine-grained access control based on the attribute-based encryption, wherein the data in the database server is protected by the access control strategy, Only users whose certificates meet the access policy can access these data, and the service provider will not know which data or the user's credentials have been accessed by the user. The scheme of this paper has the following advantages: first, the scheme of this paper maintains the privacy characteristic that is inadvertently transmitted, and provides the fine-grained access control mechanism. Second, it allows an expression-based access control strategy that directly supports AND gates, OR gates, and Threshold. Third, the communication complexity in the scheme is constant with the number of records accessed by the user. Fourth, the scheme of this paper is constructed in prime order environment. An inner product predicate encryption scheme based on prime order group with outsourced decryption function is proposed. In the attribute-based encryption scheme of the predicate encryption scheme _ attribute hiding, the cipher text both hides the plain text message and hides the attribute. Predicate encryption implements fine-grained access control for encrypted data and searches for encrypted data. However, the main disadvantage of predicate encryption in efficiency is that the size of the cipher text and the time to decrypt it will increase with the complexity of the predicates. In this paper, an inner product predicate encryption scheme based on prime order group with outsourcing and decryption function is proposed, which greatly reduces the user's overhead. In the scheme, the user provides a conversion key to the cloud server to allow the cloud server to convert the ciphertext attribute to satisfy the predicate encryption cipher text of the predicate into a short cipher text, thereby greatly reducing the time when the user decrypts the cipher text, and the cloud server does not know any user information, At the same time, the user can verify the conversion of the cloud server to ensure the correctness of the conversion.
【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN918.4

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