共查询到16条相似文献,搜索用时 375 毫秒
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本文提出一种基于公钥密码体制(Number Theory Research Unit,NTRU)选择明文攻击(Chosen Plaintext Attack,CPA)可证明安全的全同态加密方案.首先,对NTRU的密钥生成算法进行改进,通过格上的高斯抽象算法生成密钥对,避免了有效的格攻击,同时,没有改变密钥的分布.然后,基于改进的NTRU加密算法,利用Flattening技术,构造了一个全同态加密体制,并在标准模型下证明方案是选择明文攻击不可区分性IND-CPA安全的. 相似文献
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Falcon是通过NIST第一轮筛选的唯一的基于NTRU格的签名方案.相较于其它的签名设计,Falcon的公钥长度和签名长度都较短,可有效降低通信的复杂度.它的劣势在于算法设计复杂,特别是其中的密钥生成算法和快速傅里叶采样算法难以理解且需要精细实现.本文分析了在内存资源受限的设备中实现Falcon签名方案的可行性,经过优化后,运行Falcon签名算法需要的动态内存降低到参考实现的37%.采用本文提出的实现方法,则签名需要334.7 ms,签名验证需要6.16 ms. 相似文献
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当前基于格设计的能够抵抗量子计算机攻击的签名方案是基于数论难题的传统签名方案的热门候选替代。通过Fiat-Shamir变换以及拒绝采样技术构造格签名是一种重要方法,共有5个格签名方案提交到美国国家标准与技术局的后量子算法项目中,基于Fiat-Shamir变换进行设计的有两个方案。其中Dilithium是基于模错误学习(MLWE)问题构造的Fiat Shamir签名,它的一个特性是在签名算法中使用了高效简洁的均匀采样。Dilithium签名方案构造在一般格上,为了获得更紧凑的公钥尺寸,Dilithium对公钥进行了压缩。另一方面,NTRU格上的密码方案比一般格上的密码方案在效率和参数尺寸上有更大的优势,该文给出了Dilithium签名在NTRU格上的一个高效变种方案,在继承Dilithium简洁设计的基础上,综合了NTRU和拒绝采样的技术优势而无需额外的压缩处理,进一步提升了基于格的Fiat-Shamir签名的效率。 相似文献
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全同态加密可以用来解决云计算环境中的隐私保护问题,然而现有体制具有系统参数大、效率低的缺点.针对现有攻击技术,首先设计了一种高效的NTRU格上的基于身份公钥加密体制,无需借助额外的安全性假设,具有更高的安全性和更小的系统参数.之后,基于近似特征向量技术,构造了一种高效的全同态加密转化方式.通过将以上两种方法结合,给出了一种高效的基于身份全同态加密体制.和现有体制相比,除了不需要计算密钥、实现了真正意义上的基于身份特性以外,还减小了密钥、密文尺寸,提高了计算和传输效率. 相似文献
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Efficient identity-based fully homomorphic encryption over NTRU 总被引:1,自引:0,他引:1
Fully homomorphic encryption is the best solution for solving privacy concerns for data over cloud so far,while large public key size is a general shortcoming for existing schemes.First,by introducing the concept of Kullback-Leibler divergence,an identity-based public key scheme over NTRU lattice with modified ciphertext form was proposed.Analysis on parameter setting showed its small key size and ciphertext size,and experiments revealed its high computational efficiency.Second,with the idea of approximate eigenvector,an improved method to convert the scheme into an identity-based fully homomorphic encryption one was put forward to further reduce ciphertext size.Compared with existing schemes,the converted scheme not only abandons evaluation keys to make it fully identity-based,but also has smaller keys and ciphertext,which results in higher computational and transmission efficiency. 相似文献
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The previous identity-based homomorphic encryption schemes from lattice was analyzed.That the high complexity in previous schemes was mainly caused by trapdoor generation and preimage sampling was pointed out.A new solution was proposed.A novel identity-based encryption scheme from lattice by combining new trapdoor function and dual-LWE algorithm organically was constructed,and it was transformed to an identity-based fully homomorphic encryption scheme from lattice by employing the idea of eigenvector.Comparative analysis shows that the scheme’s complexity of trapdoor generation has a significant reduction,the complexity of preimage sampling has a nearly three-fold reduction,and the SIVP approximation factor has a times reduction.The security of the proposed scheme strictly reduces to the hardness of decisional learning with errors problem in the standard model. 相似文献
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User revocation is necessary to the practical application of identity-based proxy re-signature scheme.To solve the problem that the existing identity-based proxy re-signature schemes cannot provide revocation functionality,the notion of revocable identity-based proxy re-signature was introduced.Furthermore,the formal definition and security model of revocable identity-based proxy re-signature were presented.Based on proxy re-signature scheme and binary tree structure,a revocable identity-based proxy re-signature scheme was proposed.In the proposed,scheme,the user's signing key consists of two parts,a secret key and an update key.The secret key transmitted over the secure channel is fixed,but the update key broadcasted by the public channel is periodically changed.Only the user who has not been revoked can obtain the update key,and then randomize the secret key and update the key to generate the corresponding signature key of the current time period.In the standard model,the proposed scheme is proved to be existentially unforgeable against adaptive chosen-identity and chosen-message attacks.In addition,the proposed scheme has properties of bidirectionality and multi-use,and can resist signing key exposure attacks.The analysis results show that the proposed scheme can efficiently revoke the user and update the user’s key,and thus it has good scalability. 相似文献
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国产密码算法SM9是我国自主设计的标识密码方案,现已受到各界的广泛关注。为了解决现有属性签名(ABS)方案验签效率不高这一问题,该文基于国密SM9算法构造新的支持树形访问策略的属性签名方案,该方案的验签操作仅需1次双线性对映射和1次指数运算。此外,所提方案具有签名者身份可追踪功能,防止恶意签名者利用属性签名的匿名性进行非法签名操作,从而避免传统属性签名中无条件匿名性下的签名滥用问题。安全分析结果表明所提方案在随机谕言机模型下具有不可伪造性,同时也可抗合谋攻击。与现有的可追踪属性签名方案相比,所提方案的追踪算法效率更高,签名与验签开销也更低。实验结果表明,所提方案验签算法的计算复杂度与策略规模无关,完成1次验签算法仅需2 ms。 相似文献