A redactable blockchain allows authorized individuals to remove or replace undesirable content,offering the ability to remove illegal or unwanted information.Access control is a mechanism that limits data visibility a...A redactable blockchain allows authorized individuals to remove or replace undesirable content,offering the ability to remove illegal or unwanted information.Access control is a mechanism that limits data visibility and ensures that only authorized users can decrypt and access encrypted information,playing a crucial role in addressing privacy concerns and securing the data stored on a blockchain.Redactability and access control are both essential components when implementing a regulated consortium blockchain in real-world situations to ensure the secure sharing of data while removing undesirable content.We propose a decentralized consortium blockchain system prototype that supports redactability and access control.Through the development of a prototype blockchain system,we investigate the feasibility of combining these approaches and demonstrate that it is possible to implement a redactable blockchain with access control in a consortium blockchain setting.展开更多
Chameleon hash is the main primitive to construct a chameleon signature scheme which provides nonrepudiation and non-transferability simultaneously. However, the initial chameleon hash schemes suffer from the key expo...Chameleon hash is the main primitive to construct a chameleon signature scheme which provides nonrepudiation and non-transferability simultaneously. However, the initial chameleon hash schemes suffer from the key exposure problem： non-transferability is based on an unsound assumption that the designated receiver is willing to abuse his private key regardless of its exposure. Recently, several key-exposure-free chameleon hashes have been constructed based on RSA assumption and SDH （strong Diffie-Hellman） assumption. In this paper, we propose a factoring-based chameleon hash scheme which is proven to enjoy all advantages of the previous schemes. In order to support it, we propose a variant Rabin signature scheme which is proven secure against a new type of attack in the random oracle model.展开更多
In a digital society,the rapid development of computer science and the Internet has greatly facilitated image applications.However,one of the public network also brings risks to both image tampering and privacy exposu...In a digital society,the rapid development of computer science and the Internet has greatly facilitated image applications.However,one of the public network also brings risks to both image tampering and privacy exposure.Image authentication is the most important approaches to verify image integrity and authenticity.However,it has been challenging for image authentication to address both issues of tampering detection and privacy protection.One aspect,image authentication requires image contents not be changed to detect tampering.The other,privacy protection needs to remove sensitive information from images,and as a result,the contents should be changed.In this paper,we propose a practical image authentication scheme constructed from chameleon hashes combined with ordinary digital signatures to make tradeoff between tampering detection and privacy protection.Our scheme allows legitimate users to modify contents of authenticated images with a privacy-aware purpose(for example,cover some sensitive areas with mosaics)according to specific rules and verify the authenticity without interaction with the original authenticator.The security of our scheme is guaranteed by the security of the underlying cryptographic primitives.Experiment results show that our scheme is efficient and practical.We believe that our work will facilitate image applications where both authentication and privacy protection are desirable.展开更多
In a digital society,the rapid development of computer science and the Internet has greatly facilitated image applications.However,one of the public network also brings risks to both image tampering and privacy exposu...In a digital society,the rapid development of computer science and the Internet has greatly facilitated image applications.However,one of the public network also brings risks to both image tampering and privacy exposure.Image authentication is the most important approaches to verify image integrity and authenticity.However,it has been cha卜lenging for image authentication to address both issues of tampering detection and privacy protection.One aspect,image authentication requires image contents not be changed to detect tampering.The other,privacy protection needs to remove sensitive information from images,and as a result,the contents should be changed.In this paper,we propose a practical image authentication scheme constructed from chameleon hashes combined with ordinary digital signatures to make tradeoff between tampering detection and privacy protection.Our scheme allows legitimate users to modify contents of authenticated images with a privacy-aware purpose(for example,cover some sensitive areas with mosaics)according to specific rules and verify the authenticity without interaction with the original authenticator.The security of our scheme is guaranteed by the security of the underlying cryptographic primitives.Experiment results show that our scheme is efficient and practical.We believe that our work will facilitate image applications where both authentication and privacy protection are desirable.展开更多
Double-authentication-preventing signature(DAPS) is a novel signature notion proposed at ESORICS2014. The double-authentication-preventing property means that any pair of signatures on two different messages with the ...Double-authentication-preventing signature(DAPS) is a novel signature notion proposed at ESORICS2014. The double-authentication-preventing property means that any pair of signatures on two different messages with the same subject will result in an immediate collapse of the signature system. A few potential applications of DAPS have been discussed by its inventors, such as providing a kind of self-enforcement to discourage certificate authority(CA) from misbehaving in public key infrastructure and offering CA some cryptographic arguments to resist legal coercion. In this study, we focus on some fundamental issues on DAPS. We propose a new definition,which is slightly weakened but still reasonable and strong enough to capture the DAPS concept. We develop the new notion of invertible chameleon hash functions with key exposure. Then we propose a generic DAPS scheme, which is provably secure if the underlying invertible chameleon hash function with key exposure is secure. We instantiate this general construction to obtain the DAPS schemes respectively based on the well-known assumptions of integer factorization, Rivest-Shamir-Adleman(RSA), and computational Diffie-Hellman(CDH). They are more efficient than previous DAPS schemes. Furthermore, unlike previous constructions, the trusted setup condition is not needed by our DAPS schemes based on RSA and CDH.展开更多
为了进一步提高平台配置远程证明机制的实用性,针对RAMT(remote attestation based on Merkle hashtree)方案的不足,基于Chameleon哈希算法,采用软件分组的思想,改进了RAMT方案,给出了实验证明。认真讨论了RAMT方案的特点,详细描述了改...为了进一步提高平台配置远程证明机制的实用性,针对RAMT(remote attestation based on Merkle hashtree)方案的不足,基于Chameleon哈希算法,采用软件分组的思想,改进了RAMT方案,给出了实验证明。认真讨论了RAMT方案的特点,详细描述了改进后的RAMT方案的体系结构、度量及验证过程,并深入讨论了新机制的特点。实验结果表明,新机制不仅提高了远程证明机制的可伸缩性,而且进一步增强了隐私保护能力,从而进一步提高了方案的实用性。展开更多
基金supported by the National Key Research and Development Program of China(2020YFB1005900)。
文摘A redactable blockchain allows authorized individuals to remove or replace undesirable content,offering the ability to remove illegal or unwanted information.Access control is a mechanism that limits data visibility and ensures that only authorized users can decrypt and access encrypted information,playing a crucial role in addressing privacy concerns and securing the data stored on a blockchain.Redactability and access control are both essential components when implementing a regulated consortium blockchain in real-world situations to ensure the secure sharing of data while removing undesirable content.We propose a decentralized consortium blockchain system prototype that supports redactability and access control.Through the development of a prototype blockchain system,we investigate the feasibility of combining these approaches and demonstrate that it is possible to implement a redactable blockchain with access control in a consortium blockchain setting.
基金This work is partially supported by the National Natural Science Foundation of China under Grants No. 10271042 and No. 60373085.
文摘Chameleon hash is the main primitive to construct a chameleon signature scheme which provides nonrepudiation and non-transferability simultaneously. However, the initial chameleon hash schemes suffer from the key exposure problem： non-transferability is based on an unsound assumption that the designated receiver is willing to abuse his private key regardless of its exposure. Recently, several key-exposure-free chameleon hashes have been constructed based on RSA assumption and SDH （strong Diffie-Hellman） assumption. In this paper, we propose a factoring-based chameleon hash scheme which is proven to enjoy all advantages of the previous schemes. In order to support it, we propose a variant Rabin signature scheme which is proven secure against a new type of attack in the random oracle model.
基金National Natural Science Foundation of China(Grant Nos. 61902070, 61902289).
文摘In a digital society,the rapid development of computer science and the Internet has greatly facilitated image applications.However,one of the public network also brings risks to both image tampering and privacy exposure.Image authentication is the most important approaches to verify image integrity and authenticity.However,it has been challenging for image authentication to address both issues of tampering detection and privacy protection.One aspect,image authentication requires image contents not be changed to detect tampering.The other,privacy protection needs to remove sensitive information from images,and as a result,the contents should be changed.In this paper,we propose a practical image authentication scheme constructed from chameleon hashes combined with ordinary digital signatures to make tradeoff between tampering detection and privacy protection.Our scheme allows legitimate users to modify contents of authenticated images with a privacy-aware purpose(for example,cover some sensitive areas with mosaics)according to specific rules and verify the authenticity without interaction with the original authenticator.The security of our scheme is guaranteed by the security of the underlying cryptographic primitives.Experiment results show that our scheme is efficient and practical.We believe that our work will facilitate image applications where both authentication and privacy protection are desirable.
基金supported by National Natural Science Foundation of China(Grant Nos.61902070,61902289).
文摘In a digital society,the rapid development of computer science and the Internet has greatly facilitated image applications.However,one of the public network also brings risks to both image tampering and privacy exposure.Image authentication is the most important approaches to verify image integrity and authenticity.However,it has been cha卜lenging for image authentication to address both issues of tampering detection and privacy protection.One aspect,image authentication requires image contents not be changed to detect tampering.The other,privacy protection needs to remove sensitive information from images,and as a result,the contents should be changed.In this paper,we propose a practical image authentication scheme constructed from chameleon hashes combined with ordinary digital signatures to make tradeoff between tampering detection and privacy protection.Our scheme allows legitimate users to modify contents of authenticated images with a privacy-aware purpose(for example,cover some sensitive areas with mosaics)according to specific rules and verify the authenticity without interaction with the original authenticator.The security of our scheme is guaranteed by the security of the underlying cryptographic primitives.Experiment results show that our scheme is efficient and practical.We believe that our work will facilitate image applications where both authentication and privacy protection are desirable.
基金Project supported by the National Natural Science Foundation of China(Nos.61202475,61133014,and 61472114)the Science and Technology Planning Key Project of Shandong Universities,China(No.J18KA326)the Science and Technology Planning Key Project of Guangdong Province,China(No.2016B010124014)
文摘Double-authentication-preventing signature(DAPS) is a novel signature notion proposed at ESORICS2014. The double-authentication-preventing property means that any pair of signatures on two different messages with the same subject will result in an immediate collapse of the signature system. A few potential applications of DAPS have been discussed by its inventors, such as providing a kind of self-enforcement to discourage certificate authority(CA) from misbehaving in public key infrastructure and offering CA some cryptographic arguments to resist legal coercion. In this study, we focus on some fundamental issues on DAPS. We propose a new definition,which is slightly weakened but still reasonable and strong enough to capture the DAPS concept. We develop the new notion of invertible chameleon hash functions with key exposure. Then we propose a generic DAPS scheme, which is provably secure if the underlying invertible chameleon hash function with key exposure is secure. We instantiate this general construction to obtain the DAPS schemes respectively based on the well-known assumptions of integer factorization, Rivest-Shamir-Adleman(RSA), and computational Diffie-Hellman(CDH). They are more efficient than previous DAPS schemes. Furthermore, unlike previous constructions, the trusted setup condition is not needed by our DAPS schemes based on RSA and CDH.
基金Supported by the Communication Security Foundation of China under Grant Nos.J641, 0130 (国家通信保密基金)the National Natural Science Foundation of China under Grant No.69931010 (国家自然科学基金)
文摘为了进一步提高平台配置远程证明机制的实用性,针对RAMT(remote attestation based on Merkle hashtree)方案的不足,基于Chameleon哈希算法,采用软件分组的思想,改进了RAMT方案,给出了实验证明。认真讨论了RAMT方案的特点,详细描述了改进后的RAMT方案的体系结构、度量及验证过程,并深入讨论了新机制的特点。实验结果表明,新机制不仅提高了远程证明机制的可伸缩性,而且进一步增强了隐私保护能力,从而进一步提高了方案的实用性。
