共查询到20条相似文献,搜索用时 31 毫秒
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2010年,Jin等人和Zhang在标准模型下分别设计了一个基于身份的签密方案,并且声称在标准模型下满足IND—CCA的保密安全性和EUF—CMA的不可伪造安全性。通过对这两个方案的安全性进行详细的分析,发现它们并不满足其所声称的安全强度。在严格的签密定义和安全模型下,明确地给出了对这两个方案的实际有效的攻击。最后,进一步分析和总结了这两个方案在其他常用的安全定义下的安全强度。 相似文献
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In view of the existing efficiency and security problems of lattice based signcryption,with the ABB16’s signature scheme ring-TESLA,a signcryption scheme without trapdoor named RLWE-SC was constructed,which achieved indistinguish ability against adaptive chosen cipher text attack (IND-CCA2) security and strongly existential unforgeability against chosen message attack (SUF-CMA) security respectively in terms of confidentiality and authentication based on the problem of learning with errors on ring.The size of the public and private keys was optimized by the construction on the ring.The complex trapdoor generation and preimage sample calculation was avoided by the structure without trapdoor.Efficiency analysis and experiment shows that RLWE-SC has better computational and communication performance than other similar lattice-based signcryption schemes with the same security strength. 相似文献
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在云计算应用中,确保消息的机密性和不可伪造性,同时判断不同密文对应明文的等价性显得至关重要。具有密文等值测试功能的签密方案可以实现此类安全目标。该文基于无证书公钥密码环境,设计了一个具有密文等值测试功能的无证书签密方案(CLSCET)。首先,提出了无证书密文等值测试签密方案的框架和安全模型,定义了两类具有不同攻击能力的敌手和3类安全目标。然后构造了具体的无证书密文等值测试签密方案,并分析了方案的正确性。最后,基于随机预言模型,证明该文方案满足选择密文攻击下的单向性(OW-CCA)、选择密文攻击下的不可区分性(IND-CCA2)和选择消息攻击下的不可伪造性(EUF-CMA)安全。与现有近似方案相比,该文方案满足IND-CCA2的机密性、EUF-CMA的不可伪造性和OW-CCA的密文单向性。 相似文献
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签密能高效地同时完成数据加密与认证,可用于设计紧凑的安全通信协议.签密中的仲裁机制用于保护签密的不可抵赖性,但同时用于仲裁的信息可能危及协议安全.本文指出签密仲裁中存在仲裁者解密攻击和仲裁机制无法保护明文完整性两种安全隐患,归纳其原因并指出解决方法.提出一个可安全仲裁的安全混合签密方案SASC,并在随机预言机模型下证明SASC方案具有IND-CCA2和UF-CMA安全性;SASC基于明文仲裁,不仅能维护明完整性而且能抵抗仲裁者解密攻击.SASC方案不增加计算量和通信量,且对明文的长度没有限制. 相似文献
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Through cryptanalysis of the improved scheme of a generalized group-oriented threshold signcryption schemes, it is found that the improved scheme can effectively resist conspiracy attack and forgery attack, but does not have semantic security and public verification function, and sends threshold signcryption by the secret secure channel, which increases the communication costs and potential safety hazards of the system. A new group-oriented publicly verifiable threshold signcryption scheme is proposed on the basis of the improved scheme, the new scheme overcomes the drawbacks of the improved scheme, which not only provides with semantic security and public verification function, but also can send threshold signcryption by the public channel. 相似文献
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In practical applications,the potential adversary may exploit partial information about the secret keys by side-channel attacks ,traditional certificateless signcryption schemes can’t resist these key-leakage attacks.A leakage-resilient certificateless signcryption scheme based on Elliptic Curve Cryptography and bilinear pairing was presented.In the random oracle,proved that the security of the scheme is based on the decisional Diffie-Hellman assumption.The scheme is also proved semantically secure against adaptive posterior chosen-ciphertext key-leakage attacks (KL-CCA2),and existentially unforgeable against chosen-message key-leakage attacks(KL-CMA).The proposed scheme was free from non-interactive zero knowledge proof system and needs no bilinear paring operation in signcryption phase.Compared with other schemes of the same kind,the proposed scheme can resist key-leakage attacks and maintains high efficiency. 相似文献
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一个可公开验证签密方案的密码分析和改进 总被引:4,自引:0,他引:4
对Lee等提出的可公开验证签密方案进行了密码分析和改进.研究了Lee方案的机密性和不可否认性,发现Lee方案的公开验证过程是以泄漏消息的机密性为代价的.提出对Lee方案的一个修改方案,修改方案克服了Lee方案中存在的安全漏洞,是一个安全的可公开验证签密方案.该修改方案的给出有助于"设计可公开验证签密方案"这一公开问题的尽快解决. 相似文献
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Concurrent signature was introduced as an efficient approach to solving the problem of fair exchange of signatures. Almost all fair exchange e-commerce protocols based on concurrent signature that have been proposed until now either do not provide message privacy protection or adopt the sign-then-encrypt scheme to provide confidentiality. However, confidentiality is an important requirement of fair exchange e-commerce protocol. In this paper, a new concept called concurrent signcryption which
combines the concepts of concurrent signature and signcryption together to resolve the confidentiality problem in e-commerce systems based on concurrent signature. We also propose a concurrent signcryption scheme using bilinear pairings and prove its security in the random oracle model. Compared with the sign-then-encrypt scheme using bilinear pairings, our scheme enjoys shorter
message length and less operation cost. Moreover, in our scheme the two ambiguous signcryptions can be published in any order. 相似文献
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In 2010,Liu,et al.proposed a certificateless signcryption scheme in the standard model,but many analyses revealed that Liu's scheme was insecure in fact.To overcome the disadvantages,the scheme was improved and a certificateless generalized signcryption scheme was constructed.In addition,a formal security model for the proposed scheme against the malicious-but-passive KGC attacks was introduced.Furthermore,the proposed scheme was proven to be secure under the decisional bilinear Diffie-Hellman and the computational Diffie-Hellman intractability assumptions in the standard model.Numerical results illustrate that the proposed algorithm is efficient. 相似文献
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基于身份的可快速撤销代理权的代理签密方案 总被引:2,自引:0,他引:2
在代理签密方案中,一个被指定的代理签密人可以代表原始签密人生成有效的代理签密。然而,现有的代理签密方案都没有解决代理撤销问题,即如何收回代理签密人的签密权利。本文基于双线性对,提出了一个新的基于身份的代理签密方案,所提方案引入一个安全中介SEM,其作用是:帮助合法的代理签密人生成有效的代理签密;监督代理签密人是否按照授权证书的规定签名;检查代理签密人的签密权利是否被撤销。新方案不仅满足代理签密方案的所有安全要求,而且代理签密人只有与SEM合作才能生成有效的代理签密,使得方案具有快速撤销的功能。 相似文献
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为解决发送者和接收者都具有匿名性的基于属性签密方案中密钥泄露的问题,将密钥隔离机制引入到基于属性签密方案中,给出了基于属性密钥隔离签密的形式化定义和安全模型,构建了随机预言模型下安全的基于属性的密钥隔离签密方案。改进后的方案不仅没有失去原有的双向匿名性,而且满足前向安全性和后向安全性的要求,减轻了密钥泄露带来的危害。最后在安全模型的基础上,给出了双向匿名的基于属性的密钥隔离签密的机密性、认证性和匿名性的安全性证明。 相似文献