How to signcrypt a message to designated group

In an open network environment, the protection of group communication is a crucial problem. In this article, a novel broadcast group-oriented signcryption scheme is presented for group communication scenarios in distributed networks. Anyone in this scheme can signcrypt a message and distribute it to a designated group, and any member in the receiving group can unsigncrypt the ciphertext. The ciphertext and public key in the scheme are of constant size. In addition, this new scheme offers public verification of the ciphertext. This property is very important to the large-scale group communication since the gateway can filter the incorrect ciphertext and alleviate the receiver's workload. Finally, a proof in the random oracle model is given to show that the scheme is secure against chosen ciphertext attack and existential forgery.     

ANSYS有限元网格划分浅析

为提高有限元数值计算的精度和对复合材料结构及力学分析的准确性，结合实例阐述了有限元网格划分复合材料结构件的方法和过程，指出了采用ANSYS有限元分析软件在网格划分时应注意的技术问题，并对进行ANSYS网格划分采用的方法、工具进行了详细的分析和论述，研究认为，对于单一模型的分析可采用自由网格划分方法；对于尺寸变化的系列模型分析，则应考虑采用对应网格划分方法，同时应保证划分得到的结点均匀分布在指定路径上。     

一种通用的指定验证者环签名方案的改进

Li-Wang(2006)提出了一种通用指定验证者环签名方案(UDVRS)。该方案允许签名者指定一个验证者并产生一个指定验证者环签名,使得只有指定验证者才能验证该环签名。通过对Li-Wang提出的通用环签名方案进行分析,指出了该方案并不满足指定验证者性质,给出了攻击方法。为避免该缺陷,对Li-Wang通用指定验证者环签名方案进行改进,改进后的方案是可证安全的。     

一个改进的强指定验证者签密方案

Sujata等人在2012年提出了一个基于离散对数的强指定验证者签密方案,然而分析可知Sujata 等人的方案无法抵抗授权攻击,并且验证权具有可委托性。针对上述不足,给出一个改进的强指定验证者签密方案,仅有指定的验证者才能验证签密密文的有效性;此外,指定的验证者能够生成一个与原始签密密文不可区分的签密副本。安全分析表明,该方案不仅能够抵抗适应性选择明文攻击,而且在提供认证的同时可保证签密密文的不可伪造性。由于该方案的上述优越性能,在实际生活中具有广泛的应用前景,如区块链、电子投票、电子招标等场景。     

对一类强指定验证者签名方案的分析与改进

针对若干强指定验证者签名方案所存在的安全问题,给出了对一类新的高效的基于身份的强指定验证者签名方案的分析,指出该方案不具备强指定验证者签名应有的特性,并针对该方案所存在的缺陷给出了一种伪造攻击,利用该攻击任何第三方即使没有签名者或验证者的私钥也可以生成有效的签名.最后提出了一种新的基于身份的强指定验证者签名方案,并在随机预言机模型中基于双线性Diffie-Hellman假设给出了其形式化的安全性证明,该方案与已有方案相比具有更高的效率,且满足强指定验证者签名的所有性质.     

无证书的广义指定多个验证者签名体制*

提出了无证书的广义指定多个验证者的签名体制,将指定单个验证者签名方案扩展到了指定多个验证者的签名方案。该方案满足所有无证书体制下指定验证者签名所要满足的安全要求,它的不可伪造性依赖于BDH假设,并且在随机预言模型下证明了该方案能够抵抗适应性选择消息和身份攻击。     

A provably secure code‐based short signature scheme and its nontransferable variant

Signatures with partially message recovery in which some parts of messages are not transmitted with signatures to make them shorter are helpful where bandwidth is one of the critical concern. This primitive is especially used for signing short messages in applications such as time stamping, certified email services, and identity‐based cryptosystems. In this paper, to have quantum‐attack‐resistant short signatures, the first signature scheme with partially message recovery based on coding theory is presented. Next, it is shown that the proposal is secure under Goppa Parametrized Bounded Decoding and the Goppa Code Distinguishing assumptions in the random oracle model. Relying on the partially message recovery property, the proposal is shorter than Dallot signature scheme, the only provably secure and practical code‐based signature scheme, while it preserves Dallot signature efficiency. We should highlight that our scheme can be used as a building block to construct short code‐based signature schemes with special properties. To show this, we present a provably secure short designated verifier signature scheme, a nontransferable form of short signatures, which is used in electronic voting and deniable authentication protocols.     

指定接收人的（t，n）门限代理签名方案

为了满足原始签名人的意愿,提出一个指定接收人的门限代理签名方案。在代理授权的过程中,原始签名人通过授权指定代理签名的接收人,代理签名人在验证原始签名人所提供的授权参数合法的基础上产生代理签名密钥,从而可以产生代理签名。提出的签名方案具有代理签名方案的基本安全要求：不仅验证人在验证代理签名之后只能确信代理签名是代表原始签名人的签名而无法确定代理签名者身份;当出现争议时,原始签名人可通过代理群管理员追查出代理签名人的身份;而且保证代理签名人只能对所指定的签名接收人产生代表原始签名人的有效代理签名,从而防止了代理签名权利的滥用。     

A novel ID-based designated verifier signature scheme

In a designated verifier signature scheme, only the designated verifier can verify the validity of a signature. This paper studies an Identity-based Strong Designated Verifier Signature (IBSDVS) scheme based on bilinear pairings by combining ID-based cryptosystem with the designated verifier signature scheme. We analyze the security of the scheme and the result shows that the security of our proposed scheme is closely related to the Bilinear Diffie-Hellman problem and the scheme is against delegatability attack.     

J2EE应用服务器内置部署器的设计与实现

本文提出了一种J2EE应用服务器内置部署器的体系结构，并且给出了其实现方案。它完全符合J2EE规范的相应要求，并且具有良好的可扩展性，能够满足企业应用部署的要求。这些技术已经被成功地应用于我们开发的J2EE应用服务器中。