Verifiably encrypted signatures are employed when a signer wants to sign a message for a verifier but does not want the verifier to possess his signature on the message until some certain requirements of his are satis...Verifiably encrypted signatures are employed when a signer wants to sign a message for a verifier but does not want the verifier to possess his signature on the message until some certain requirements of his are satisfied. This paper presented new verifiably encrypted signatures from bilinear pairings. The proposed signatures share the properties of simplicity and efficiency with existing verifiably encrypted signature schemes. To support the proposed scheme, it also exhibited security proofs that do not use random oracle assumption. For existential unforgeability, there exist tight security reductions from the proposed verifiably encrypted signature scheme to a strong but reasonable computational assumption.展开更多
As a special kind of digital signature, verifiably encrypted signatures are used as a building block to construct optimistic fair exchange. Many verifiably encrypted signature schemes have been proposed so far and mos...As a special kind of digital signature, verifiably encrypted signatures are used as a building block to construct optimistic fair exchange. Many verifiably encrypted signature schemes have been proposed so far and most of them were proven secure under certain complexity assumptions. In this paper, however, we find that although some schemes are secure in a single-user setting, they are not secure in a multi-user setting any more. We show that Zhang, et al. ＇ s scheme, Gorantla, et al. ＇ s scheme and Ming, et al. ＇ s scheme are vulnerable to key substitution attacks, where an adversary can generate new keys satisfying legitimate verifiably encrypted signatures created by the legitimate users. We also show that this kind of attacks can breach the fairness when they are used in fair exchange in a multi-user setting.展开更多
A non-delegatable strong designated verifier signature （NSDVS） enforces verification of a signature by a designated verifier only. The concept is useful in various commercial cryptographic applications such as copyr...A non-delegatable strong designated verifier signature （NSDVS） enforces verification of a signature by a designated verifier only. The concept is useful in various commercial cryptographic applications such as copyright protection, e-voting, and e-libraries. This paper reports the shortest NSDVS so far that consists of only two elements. The scheme is inspired by an identification scheme and Cramer et al.＇s OR-proof technique where a prover can prove that he knows at least one out two secrets. It is solidified by a symmetric key based group to group encryption algorithm. Two implementations of the algorithm are reported. The scheme is provably secure with respect to its properties of unforgeability, non-transferability, privacy of signer＇s identity, and non-delegatability.展开更多
As a new computing paradigm, outsourcing computing provides inexpensive, on-demand, convenient storage and computing services for cloud clients. For the security of outsourcing databases to the cloud, it is important ...As a new computing paradigm, outsourcing computing provides inexpensive, on-demand, convenient storage and computing services for cloud clients. For the security of outsourcing databases to the cloud, it is important to allow the user to verify the query results returned by the cloud server. So far, tremendous efforts have been carried out to study secure outsourcing computing. The existing scheme supports that the user can detect the correctness and completeness of the query results even if the cloud server returns an empty set. However, since the data owner performs the database encryption operations and uploads the encrypted database to the cloud server, they require the user to request the data owner to decrypt the query results. In this paper, we propose a new scheme, which can accurately verify the search results. Meanwhile, the users can decrypt the query results independently. Furthermore, the proposed scheme supports a large number of data owners to upload their encrypted database to the cloud server, and it can efficiently verify the query results. Besides, we can prove that our proposed solution can achieve the desired security properties.展开更多
针对外包数据库的数据机密性和完整性等安全问题,结合数据库加密和NTRU(Number Theory Research Unit)签名技术,提出一种安全有效的密钥管理方案.方案中首先用户由数据表的结构特点选择属性参数,产生数据加密密钥,对数据进行加密保护.其...针对外包数据库的数据机密性和完整性等安全问题,结合数据库加密和NTRU(Number Theory Research Unit)签名技术,提出一种安全有效的密钥管理方案.方案中首先用户由数据表的结构特点选择属性参数,产生数据加密密钥,对数据进行加密保护.其次,通过对密文数据进行基于多项式环密码体制的签名,实现数据的完整性保护.最后将密文数据和签名数据一起存放到外包数据库中,而数据加密密钥储存到本地安全数据库中,并由系统主密钥加密保护,系统主密钥和签名验证密钥安全存放在硬件安全模块中.此外,解密数据时先验证请求数据的NTRU签名,如果验证通过则可以解密数据,否则不需要解密数据.实验中分别比较了密钥管理方案中密钥生成算法以及NTRU签名的效率,结果表明该方案安全有效,并且在不同的加密算法下该密钥管理方案均是安全稳定的,可以同时提供数据机密性保护和完整保护.展开更多
文摘Verifiably encrypted signatures are employed when a signer wants to sign a message for a verifier but does not want the verifier to possess his signature on the message until some certain requirements of his are satisfied. This paper presented new verifiably encrypted signatures from bilinear pairings. The proposed signatures share the properties of simplicity and efficiency with existing verifiably encrypted signature schemes. To support the proposed scheme, it also exhibited security proofs that do not use random oracle assumption. For existential unforgeability, there exist tight security reductions from the proposed verifiably encrypted signature scheme to a strong but reasonable computational assumption.
基金Supported by the National High Technology Research and Development Programme of China （ No. 2008AA092301 ） and the National Natural Science Foundation of China （No. 50879014）.
文摘As a special kind of digital signature, verifiably encrypted signatures are used as a building block to construct optimistic fair exchange. Many verifiably encrypted signature schemes have been proposed so far and most of them were proven secure under certain complexity assumptions. In this paper, however, we find that although some schemes are secure in a single-user setting, they are not secure in a multi-user setting any more. We show that Zhang, et al. ＇ s scheme, Gorantla, et al. ＇ s scheme and Ming, et al. ＇ s scheme are vulnerable to key substitution attacks, where an adversary can generate new keys satisfying legitimate verifiably encrypted signatures created by the legitimate users. We also show that this kind of attacks can breach the fairness when they are used in fair exchange in a multi-user setting.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant Nos. 61003244, 61100224）, Doctoral Fund of Ministry of Education of China （20120171110027）.Fundamental Research Funds for the Central Universities （1 11gpy71）.
文摘A non-delegatable strong designated verifier signature （NSDVS） enforces verification of a signature by a designated verifier only. The concept is useful in various commercial cryptographic applications such as copyright protection, e-voting, and e-libraries. This paper reports the shortest NSDVS so far that consists of only two elements. The scheme is inspired by an identification scheme and Cramer et al.＇s OR-proof technique where a prover can prove that he knows at least one out two secrets. It is solidified by a symmetric key based group to group encryption algorithm. Two implementations of the algorithm are reported. The scheme is provably secure with respect to its properties of unforgeability, non-transferability, privacy of signer＇s identity, and non-delegatability.
基金Supported by the National Key Research and Development Program of China(2017YFB0802000)the National Natural Science Foundation of China(61572390,U1736111)+1 种基金the Natural Science Foundation of Ningbo City(201601HJ-B01382)the Open Foundation of Key Laboratory of Cognitive Radio and Information Processing of Ministry of Education(Guilin University of Electronic Technology)(CRKL160202)
文摘As a new computing paradigm, outsourcing computing provides inexpensive, on-demand, convenient storage and computing services for cloud clients. For the security of outsourcing databases to the cloud, it is important to allow the user to verify the query results returned by the cloud server. So far, tremendous efforts have been carried out to study secure outsourcing computing. The existing scheme supports that the user can detect the correctness and completeness of the query results even if the cloud server returns an empty set. However, since the data owner performs the database encryption operations and uploads the encrypted database to the cloud server, they require the user to request the data owner to decrypt the query results. In this paper, we propose a new scheme, which can accurately verify the search results. Meanwhile, the users can decrypt the query results independently. Furthermore, the proposed scheme supports a large number of data owners to upload their encrypted database to the cloud server, and it can efficiently verify the query results. Besides, we can prove that our proposed solution can achieve the desired security properties.
文摘针对外包数据库的数据机密性和完整性等安全问题,结合数据库加密和NTRU(Number Theory Research Unit)签名技术,提出一种安全有效的密钥管理方案.方案中首先用户由数据表的结构特点选择属性参数,产生数据加密密钥,对数据进行加密保护.其次,通过对密文数据进行基于多项式环密码体制的签名,实现数据的完整性保护.最后将密文数据和签名数据一起存放到外包数据库中,而数据加密密钥储存到本地安全数据库中,并由系统主密钥加密保护,系统主密钥和签名验证密钥安全存放在硬件安全模块中.此外,解密数据时先验证请求数据的NTRU签名,如果验证通过则可以解密数据,否则不需要解密数据.实验中分别比较了密钥管理方案中密钥生成算法以及NTRU签名的效率,结果表明该方案安全有效,并且在不同的加密算法下该密钥管理方案均是安全稳定的,可以同时提供数据机密性保护和完整保护.
基金Supported by the National Natural Science Foundation of China under Grant No.60673075the Doctoral Program Foundation of Chinese Ministry of Education under Grant No.20050614018~~
