一种可转换的认证加密方案

现有的认证加密方案只考虑了如何在验证消息的有效性时不使用Hash函数和消息冗余函数的情况，或只讨论在验证时签名的可转换性问题。针对这种情况，该文基于椭圆曲线密码体制设计了一个可转换的且不需要Hash函数和消息冗余函数的认证加密方案，而且方案中签名的转换过程不需要签名者的合作，并对该方案进行了性能分析。     

一种基于公钥自证明的认证加密方案

针对基于认证证书的数字签名方案中公钥集中保存,系统容易受到主动攻击的缺点,提出了一种新的基于公钥自证明的认证加密方案。该方案中用户匿名注册,并获得由用户与CA共同产生的公钥证明,可以根据用户公钥证明推导其公钥;通信双方的公钥认证与消息签名结合在一起,由消息接收者在认证签名、恢复消息时完成公钥认证,因而减少了存储空间、通信量和计算量。     

分工式门限认证加密方案

(t,n)门限认证加密方案允许t个以上签名方产生指定接收方的认证加密签名,使得只有指定的接收方能够恢复消息和验证消息的完整性,而其他人却无法做到这一点.最近,在Tseng和Jan的认证加密方案的基础上,Chung等构造了一个(t,n)门限认证加密方案.该方案运用了分工式签名技术,有效地减轻了签名方的负担.然而,该文作者对该方案的安全性仅进行了解释性说明.目前,文献中没有对分工式门限认证加密的形式化刻画,没有出现可证安全分工式门限认证加密方案.事实上,Chung等的分工式门限认证加密方案存在设计上的缺陷.文中给出了分工式门限认证加密方案的形式化模型和安全模型,基于双线性映射构造了一个新的分工式门限认证加密方案.在随机预言机模型下,证明了该方案对于适应性选择密文攻击是语义安全的,该方案对于适应性选择消息攻击是存在性不可伪造的.方案的安全性可规约到计算性Diffie-Hellman(CDH)困难假设和决定性双线性Diffie-Hellman困难假设(DBDH).     

两个具有语义安全的可转换认证加密方案

提出了两个具有语义安全的可转换认证加密方案,方案具有以下性质:能够提供消息的语义安全——任何攻击者,即使获得了一个认证加密签名,也无法确定他所猜测的消息是否为真正的消息;收到签名后,接收者只用自己的私钥和签名者的公钥来恢复、验证消息;如果签名者后来否定签名,接收者可以通过恢复的消息和其它一些相关参数向任何第三方证明签名者的欺骗。     

基于身份认证的手机支付系统的设计与实现

通过椭圆曲线上的Weil配对的双线性和Euler准测，提出了一种基于身份认证的签名加密方案。它不仅可以获得较快的加密解密速度，辨别消息的真伪，还能抵抗重发密文的攻击。该方案降低了公钥的存储和管理成本，签名长度大约是Guillou Quisquater签名长度的1/4。针对手机自身的特点，设计了一种基于该签名加密方案的手机支付系统，并进行了安全性和有效性分析。     

基于身份认证的离线电子支付系统安全性研究

利用椭圆曲线上Weil配对的双线性性质和Euler准测,提出了一种新的基于身份认证的签名加密方案.它集密钥交换、数字签名、和数据加密解密功能于一体,不仅可以获得较快的加密解密速度,辨别消息的真伪,还能抵抗重发密文的攻击.该方案降低了公钥的存储和管理成本,签名长度大约是Guillou-Quisquater签名长度的1/4.利用该方案构造了一种安全的离线电子支付系统,能够有效地防止重复消费、窃听、篡改和高手段的犯罪,并对该系统进行了安全性和有效性分析.     

代理可转换认证加密方案

结合代理签名和可转换认证加密两种方案,提出了代理可转换认证加密方案和(t,n)门限代理方案。方案能够使一个代理人代理被代理人认证加密一个消息给某个特定的接收者。     

无线体域网中节点认证方案研究

针对无线体域网中节点身份认证问题,本文在传统椭圆曲线签名算法的基础上,提出了一种新的在线\离线椭圆曲线签名方案。该方案在未确定签名消息之前进行离线签名,在确定要加密的消息和身份私钥之后进行在线签名。对该方案进行了安全性分析,证明了其具有正确性、不可伪造、不可否认、抵御重放攻击、轻量级的优点,同时通过运算量的对比分析,表明该方案由于取消了求逆运算,具有较大的计算优势。     

基于可截取签名和属性加密的云存储访问控制方案

现有的云存储访问控制方案只能根据用户属性的不同发送不同的消息,因而消息利用率不高。针对这一缺陷,首先设计了一个基于ElGamal的可截取签名方案,然后基于该可截取签名方案结合属性加密体制提出了一种新的云存储访问控制方案。新方案在实现数据加密的同时,提供了细粒度的访问控制,将符合属性的子消息发送给相应的用户,提高了消息的利用率,具有更强的应用性。     

可认证安全的多接收者签密方案

利用椭圆曲线上的双线性映射,提出了一个新的可认证安全的多接收者签密方案,该方案的特点在于基于身份,集签名与加密于一体,实现了可公开认证性,同时该方案中只有指定的接收者才能恢复出相应的消息.经过分析,所提的方案是高效的.     

Authenticated encryption schemes with message linkages for message flows

Two efficient authenticated encryption schemes with message linkages are proposed. One is a basic scheme, that it has the better performance in comparison with the all previously proposed schemes in terms of the communication and the computation costs. However, it has a property as same as the previously proposed schemes, that the message blocks can be recovered only after the entire signature blocks have been received. Therefore, the basic scheme is applicable to encrypt all-or-nothing flow. Thus, we improve the basic scheme and also propose a generalized scheme, which allows the receiver to recover the partial message blocks before receiving the entire signature blocks. That is, the receiver may perform the receiving and the recovering processes simultaneously. Therefore, the generalized scheme is applicable to message flows. The generalized scheme requires smaller bandwidth and computational time as compared to the previously proposed authenticated encryption schemes with message linkages for message flows.     

Improvements of authenticated encryption schemes with message linkages for message flows

Recently, Tseng et al. proposed two authenticated encryption schemes (basic scheme and generalized scheme) with message linkages, which are efficient in terms of the communication and computation costs in comparison with all the previously proposed schemes. The basic authenticated encryption scheme suited for only after receiving the entire signature blocks, the recipient can then recover the message blocks. In order to allow the receiver to perform the receiving and the recovering processes simultaneously according to application requirements and the transmission efficiency of the network, the generalized authenticated encryption scheme was then proposed. In this paper, we show that both Tseng et al.’s authenticated encryption schemes do not achieve integrity and authentication. Improvements are then proposed to repair the weaknesses.     

Convertible multi-authenticated encryption scheme

A convertible authenticated encryption (CAE) scheme allows the signer to generate a valid authenticated ciphertext on his chosen message such that only the designated recipient can retrieve the message. Further, the recipient has the ability to convert the authenticated ciphertext into ordinary signature in case of a dispute or repudiation. The previous proposed CAE schemes can only allow one signer to produce the authenticated ciphertext. It might be inadequate for multiparty environments. In this paper, we elaborate on the merits of CAE and multi-signature schemes to propose a convertible multi-authenticated encryption scheme which has the following advantages: (i) The size of the generated authenticated ciphertext is independent of the number of total participating signers. (ii) Except for the designated recipient, no one can obtain the signed message and verify its corresponding signature. (iii) The signature is cooperatively produced by a group of signers instead of a single signer. (iv) In case of a later dispute on repudiation, the recipient has the ability to convert the authenticated ciphertext into an ordinary one for convincing anyone of the signers’ dishonesty.     

The ring authenticated encryption scheme – How to provide a clue wisely

Though cryptography is being used more and more widely in reality, it seems that there exists no scheme or a concatenation of some existing schemes that could deal soundly with such practical situations as providing a clue, where the provider of the clue may want to reserve his beneficial rights while keeping his identity secret. To address this problem, inspired by the two notions of the ring signature and the authenticated encryption signature, we propose a new type of authenticated encryption scheme, which we call the ring authenticated encryption scheme, which can enable any member of a group of persons to provide a clue to some designated recipient wisely.     

椭圆曲线上具有信息恢复的签名方案的研究

基于椭圆曲线的数字签名系统设计是目前数字签名系统设计的热点之一。论文在椭圆曲线上设计出自我鉴定公钥来建立一个新的数字签名方案,该方案利用用户标识和公钥就可以在通过签名恢复信息的同时又具备认证功能。并在此基础上提出两个扩展方案:一个满足了认证加密、恢复明文的功能;另一个则是第二个方案在处理大信息时的推广。     

公开验证认证加密方案中的第三方验证

通过对两个认证加密方案中第三方验证的分析和改进，说明了在设计一个公开验证认证加密方案中的第三方验证时，为了防止来自接收者的攻击，加入接收者的身份信息和将消息与签名验证关联都是十分必要的。     

辫群上的可转换认证加密方案

量子计算的快速发展给目前的公钥密码体制带来严重威胁,非交换的辫群为构造安全密码协议提供了新平台。基于辫群上共轭搜索问题和多重共轭搜索问题的难解性,提出一个可转换认证加密方案,只有指定的接收者才能恢复认证的原始消息;当发送者否认签名时,接收者不需要发送方的参与即可将收到的签名转换为一般签名,并向第三方证明发送者的不诚实。与基于交换代数的方案相比,该方案在抗量子攻击上更有优势。     

基于身份的环认证加密方案的改进*

环认证加密方案是加密方案与环签名方案的融合,具有这两种方案的优点。但通过研究发现,有的环认证加密方案不具有环签名的无条件匿名性的性质。为此提出了一个改进方案,并分析了其性质。