In ACM'CCS 2009,Camenisch,et al.proposed the Oblivious Transfer with Access Control(AC-OT) in which each item is associated with an attribute set and can only be available,on request,to the users who have all the ...In ACM'CCS 2009,Camenisch,et al.proposed the Oblivious Transfer with Access Control(AC-OT) in which each item is associated with an attribute set and can only be available,on request,to the users who have all the attributes in the associated set.Namely,AC-OT achieves access control policy for conjunction of attributes.Essentially,the functionality of AC-OT is equivalent to the sim-plified version that we call AC-OT-SV:for each item,one attribute is associated with it,and it is requested that only the users who possess the associated attribute can obtain the item by queries.On one hand,AC-OT-SV is a special case of AC-OT when there is just one associated attribute with each item.On the other hand,any AC-OT can be realized by an AC-OT-SV.In this paper,we first present a concrete AC-OT-SV protocol which is proved to be secure in the model defined by Camenisch,et al..Then from the protocol,interestingly,a concrete Identity-Based Encryption(IBE) with Anonymous Key Issuing(AKI) is given which is just a direct application to AC-OT-SV.By comparison,we show that the AKI protocol we present is more efficient in communications than that proposed by Chow.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
Two fast and robust digital watermarking schemes for compressed music format and MIDI format are put forward, which are suitable for on-line distribution through the Internet. For compressed music, the watermark is em...Two fast and robust digital watermarking schemes for compressed music format and MIDI format are put forward, which are suitable for on-line distribution through the Internet. For compressed music, the watermark is embedded in partially uncompressed domain and the embedding scheme is closely related to music content. For MIDI, the watermark is embedded in virtual notes that are generated and randomly hide among the MIDI notes. This paper also presents a method for controlling usage and protecting against copying of digital music contents and their associated players. The digital music contents and their players installed in one computer cannot be used if they are copied to another computer. Even in the same computer, the duplicated digital music contents are not usable. The usage associated to the music content will restrict the running time and times. Also the music can be played and it will be automatically updated after each playing. The digital music cannot be accessible if its permitted usage expires.展开更多
This paper shows several security weaknesses of a threshold authenticated encryption scheme. A new threshold authenticated encryption scheme using labor-division signature is proposed without redundancy added to messa...This paper shows several security weaknesses of a threshold authenticated encryption scheme. A new threshold authenticated encryption scheme using labor-division signature is proposed without redundancy added to message blocks. On the assumptions of EDDH problems, the proposed scheme is secure against chosen-ciphertext attacks and existentially unforgeable against the chosen- message attacks in the random oracle model.展开更多
结合云存储的应用环境,构造了一种基于密文策略属性的加密(ciphertext policy attribute based encryption,CP-ABE)技术和收敛加密技术的混合加密数据访问控制方案.该方案包括密钥发布中心、用户和云服务器三方实体,能高效、灵活、细粒...结合云存储的应用环境,构造了一种基于密文策略属性的加密(ciphertext policy attribute based encryption,CP-ABE)技术和收敛加密技术的混合加密数据访问控制方案.该方案包括密钥发布中心、用户和云服务器三方实体,能高效、灵活、细粒度地进行数据的访问控制,可提高云存储服务器的空间利用率,并使用签名技术支持数据源认证和数据完整性认证.理论分析与实验验证了该方案具有较高的实际应用价值.展开更多
文摘In ACM'CCS 2009,Camenisch,et al.proposed the Oblivious Transfer with Access Control(AC-OT) in which each item is associated with an attribute set and can only be available,on request,to the users who have all the attributes in the associated set.Namely,AC-OT achieves access control policy for conjunction of attributes.Essentially,the functionality of AC-OT is equivalent to the sim-plified version that we call AC-OT-SV:for each item,one attribute is associated with it,and it is requested that only the users who possess the associated attribute can obtain the item by queries.On one hand,AC-OT-SV is a special case of AC-OT when there is just one associated attribute with each item.On the other hand,any AC-OT can be realized by an AC-OT-SV.In this paper,we first present a concrete AC-OT-SV protocol which is proved to be secure in the model defined by Camenisch,et al..Then from the protocol,interestingly,a concrete Identity-Based Encryption(IBE) with Anonymous Key Issuing(AKI) is given which is just a direct application to AC-OT-SV.By comparison,we show that the AKI protocol we present is more efficient in communications than that proposed by Chow.
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.
文摘Two fast and robust digital watermarking schemes for compressed music format and MIDI format are put forward, which are suitable for on-line distribution through the Internet. For compressed music, the watermark is embedded in partially uncompressed domain and the embedding scheme is closely related to music content. For MIDI, the watermark is embedded in virtual notes that are generated and randomly hide among the MIDI notes. This paper also presents a method for controlling usage and protecting against copying of digital music contents and their associated players. The digital music contents and their players installed in one computer cannot be used if they are copied to another computer. Even in the same computer, the duplicated digital music contents are not usable. The usage associated to the music content will restrict the running time and times. Also the music can be played and it will be automatically updated after each playing. The digital music cannot be accessible if its permitted usage expires.
基金This research is supported by the Opening Foundation of Key Lab of Network Security and Cryptology, School of Mathematics and Computer Science, Fujian Normal University under Grant No. 09A003, and the National Natural Science Foundation of China under Grant No. 10961013.
文摘This paper shows several security weaknesses of a threshold authenticated encryption scheme. A new threshold authenticated encryption scheme using labor-division signature is proposed without redundancy added to message blocks. On the assumptions of EDDH problems, the proposed scheme is secure against chosen-ciphertext attacks and existentially unforgeable against the chosen- message attacks in the random oracle model.
文摘结合云存储的应用环境,构造了一种基于密文策略属性的加密(ciphertext policy attribute based encryption,CP-ABE)技术和收敛加密技术的混合加密数据访问控制方案.该方案包括密钥发布中心、用户和云服务器三方实体,能高效、灵活、细粒度地进行数据的访问控制,可提高云存储服务器的空间利用率,并使用签名技术支持数据源认证和数据完整性认证.理论分析与实验验证了该方案具有较高的实际应用价值.
