共查询到20条相似文献,搜索用时 62 毫秒
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在线/离线签名是利用预处理技巧提高在线签名速度的签名形式。构造了一种可以恢复消息的在线/离线签名方案。因为不需要发送消息,该方案可以大大节约传输带宽。在随机预言模型下,新方案被证明是安全的。 相似文献
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在线/离线签密不仅可以提高移动设备的计算效率,而且还可以保证数据的机密性和不可伪造性。异构密码环境下,需要考虑不同公钥密码环境之间的在线/离线签密问题。定义了从无证书密码体制到身份密码体制的在线/离线异构签密安全模型,并提出了具体的CLPKC-to-IDPKC在线/离线异构签密方案。方案执行签密运算时,不需要双线性对运算;执行解签密时,只需要2个双线性对运算。与已有在线/离线异构签密方案相比,在效率相当的情况下不存在证书管理问题,适合于计算能力受限的移动设备。通过安全性证明本文方案满足机密性和不可伪造性。最后的实验仿真分析了所提方案在线/离线签密和解签密的效率,该方案采用了独立系统参数,更适用于实际应用环境。 相似文献
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在线/离线加密方案旨在提高在线加密速度.本文研究并设计了一种基于一次函数的在线/离线短信息加密方案,它在现阶段只需要做一次函数计算,并将该方案应用在手机短信息上. 相似文献
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签密能够同时实现加密和签名的功能,并且代价小于传统方法。在线/离线技术能够有效提高签名与加密效率,适用于计算能力严格受限的移动网络终端设备。针对现有的属性签密方案实用性不强、效率低下的现状,提出了一个基于属性的在线/离线签密方案,在随机预言机模型下,利用判定双线性Diffie-Hellman倒转(l-DBDHI)问题和计算Diffie-Hellman(CDH)问题的困难性,证明了该方案满足在适应性选择密文攻击下的不可区分性以及适应性选择消息下的不可伪造性。基于属性的在线/离线签密方案虽然在密文长度方面有所增加,但该方案既可以支持保密性和认证性,又更加贴近于实际环境。 相似文献
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基于以前提出的门限签名方案的不足,给出了一种新的在线/离线门限签名方案。给出了密钥生成、离线阶段和在线阶段的具体算法步骤,并在随机预言模型下,从完备性和可靠性等方面证明了该方案的安全性,采用零知识证明验证部分签名的方法保证了方案的健壮性,并对方案的计算复杂度,存储复杂度,和通信复杂度进行了效率分析和比较,验证了方案的可行性。证明和分析结果表明,方案解决了密钥泄露问题,大大降低了离线阶段的计算量和存储量,降低了在线阶段的通信量,极大地提高了签名的响应速度,具有良好的安全性和健壮性。 相似文献
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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。 相似文献
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Puwen WeiAuthor Vitae Xiaoyun WangAuthor Vitae 《Computers & Electrical Engineering》2012,38(4):975-985
In this paper, we report our success in identifying an efficient public key encryption scheme whose formal security proof does not require a random oracle. Specifically, we focus our attention on a universal hash based public key encryption scheme proposed by Zheng and Seberry at Crypto’92. Although Zheng and Seberry’s encryption scheme is very simple and efficient, its reductionist security proof has not been provided. We show how to tweak the Zheng-Seberry scheme so that the resultant scheme not only preserves the efficiency of the original scheme but also admits provable security against adaptive chosen ciphertext attack without random oracle. For the security proof, our first attempt is based on a strong assumption called the oracle Diffie-Hellman+ assumption. This is followed by a more challenging proof that employs a weaker assumption called the adaptive decisional Diffie-Hellman assumption, which is in alignment with adaptively secure assumptions advocated by Pandey, Pass and Vaikuntanathan. 相似文献
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基于双曲线映射的签名设计了一种新型可分电子现金方案,方案中有效地加入了压缩支付和批处理支付,计算时间复杂度较小,从而使得系统的整体效率较高。另外,方案中无需可信第三方(TTP)的参与,因而系统的整体开销较小。方案的安全性基于q-SDK假设、计算离散对数困难性假设以及单向散列函数存在性假设。 相似文献
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高效无证书签名方案的安全性分析和改进 总被引:2,自引:1,他引:1
最近,张玉磊等人提出一个基于双线性对的高效无证书签名方案,通过对其提出的方案进行安全性分析,指出他们的方案对替换公钥攻击是不安全的。对张玉磊等人的方案进行了改进,在q-强Diffie-Hellman困难性假设和离散对数困难假设下,在随机预言机模型中证明改进后的方案,是存在性不可伪造的。 相似文献
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对金春花等人提出的无证书混合签密方案进行了密码分析,分析表明其方案在内部攻击模型下存在保密性攻击,基于双线性对提出了一个改进的无证书混合签密方案。在随机预言机模型中,基于间隙双线性Dif-fie-Hellman问题和计算Diffie-Hellman问题证明了改进方案的安全性。改进方案在克服原方案的安全缺陷的基础上保持了原方案的高效性。 相似文献
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At Crypto 96 Cramer and Damgård proposed an efficient, tree-based, signature scheme that is provably secure against adaptive chosen message attacks under the assumption that inverting RSA is computationally infeasible.
In this paper we show how to modify their basic construction in order to achieve a scheme that is provably secure under the assumption that factoring large composites of a certain form is hard. Our scheme is as efficient as the original Cramer Damgård solution while relying on a seemingly weaker intractability assumption. 相似文献
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This paper proposes a new public-key encryption scheme which removes one element from the public-key tuple of the original Cramer-Shoup scheme. As a result, a ciphertext is not a quadruple but a triple at the cost of a strong assumption, the third version of knowledge of exponent assumption (KEA3). Under assumptions of KEA3, a decision Diffie-Hellman (DDH) and a variant of target collision resistance (TCRv), the new scheme is proved secure against indistinguishable adaptive chosen ciphertext attack (IND-CCA2). This scheme is as efficient as Damgard ElGamal (DEG) scheme when it makes use of a well-known algorithm for product of exponentiations. The DEG scheme is recently proved IND-CCA1 secure by Bellare and Palacio in ASIACRYPT 2004 under another strong assumption. In addition to our IND-CCA2 secured scheme, we also believe that the security proof procedure itself provides a well insight for ElGamal-based encryption schemes which are secure in real world. 相似文献
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Zuhua ShaoAuthor Vitae 《Computers & Electrical Engineering》2011,37(2):136-146
In Certificate-Based Encryption, introduced by Gentry, a certificate, -or, more generally, a signature-acts not only as a certificate but also as a decryption key. However, the security model of Gentry’s scheme relies on an unrealistic assumption, where the adversary must reveal its partial private key to the challenger in attack games. In this paper, we propose an enhanced Certificate-Based Encryption scheme from pairings in the chosen-key model. We show that this scheme is semantically secure against adaptive chosen ciphertext attacks in the random oracle model under the Bilinear Diffie-Hellman (BDH) assumption. The new scheme not only solves the key escrow problem and the secure channel problem to be inherent in Identity-Based Encryption schemes, but also eliminates the unrealistic assumption of Gentry scheme. Moreover, the proposed scheme is more efficient and secure than the existing related works. 相似文献