In a strong designated verifier proxy signature scheme, a proxy signer can generate proxy signature on behalf of an original signer, but only the designated verifier can verify the validity of the proxy signature. In ...In a strong designated verifier proxy signature scheme, a proxy signer can generate proxy signature on behalf of an original signer, but only the designated verifier can verify the validity of the proxy signature. In this paper, we first define the security requirements for strong designated verifier proxy signature schemes. And then we construct an identity-based strong designated verifier proxy signature scheme. We argue that the proposed scheme satisfies all of the security requirements.展开更多
Hafizul Islam SK和G.P.Biswas最近基于椭圆曲线双线性对提出一个无证书强指定验证者签名方案,并声称该方案在三类敌手攻击模型下是可证明安全的,即第一类只得到系统公开参数和公钥的敌手,第二类可替换签名和验证者公钥的敌手,第三类可...Hafizul Islam SK和G.P.Biswas最近基于椭圆曲线双线性对提出一个无证书强指定验证者签名方案,并声称该方案在三类敌手攻击模型下是可证明安全的,即第一类只得到系统公开参数和公钥的敌手,第二类可替换签名和验证者公钥的敌手,第三类可得到系统主密钥的敌手。分析该强指定验证者签名方案不能抵抗第三类敌手的攻击,亦即第三类敌手可以伪造有效的签名。针对此缺陷,对该无证书强指定验证者签名方案做了改进,在改进方案中,验证者的秘密私钥(由参与者独立产生的私钥)参与签名的验证计算,因此有效避免了原有方案的安全缺陷。最后对改进方案作了安全性分析,说明改进方案确实能抵抗三类敌手的攻击。展开更多
In this paper an encryption-decryption algorithm based on two moduli is described: one in the real field of integers and another in the field of complex integers. Also the proper selection of cryptographic system para...In this paper an encryption-decryption algorithm based on two moduli is described: one in the real field of integers and another in the field of complex integers. Also the proper selection of cryptographic system parameters is described. Several numeric illustrations explain step-by-step how to precondition a plaintext, how to select secret control parameters, how to ensure feasibility of all private keys and how to avoid ambiguity in the process of information recovery. The proposed cryptographic system is faster than most of known public key cryptosystems, since it requires a small number of multiplications and additions, and does not require exponentiations for its implementation.展开更多
Prime integers and their generalizations play important roles in protocols for secure transmission of information via open channels of telecommunication networks. Generation of multidigit large primes in the design st...Prime integers and their generalizations play important roles in protocols for secure transmission of information via open channels of telecommunication networks. Generation of multidigit large primes in the design stage of a cryptographic system is a formidable task. Fermat primality checking is one of the simplest of all tests. Unfortunately, there are composite integers (called Carmichael numbers) that are not detectable by the Fermat test. In this paper we consider modular arithmetic based on complex integers;and provide several tests that verify the primality of real integers. Although the new tests detect most Carmichael numbers, there are a small percentage of them that escape these tests.展开更多
基金Supported by the National Natural Science Foun-dation of Chinafor Distinguished Young Scholars(60225007) the Na-tional Research Fundfor the Doctoral Programof Higher Education ofChina(20020248024) the Science and Technology Research Pro-ject of Shanghai (04DZ07067)
文摘In a strong designated verifier proxy signature scheme, a proxy signer can generate proxy signature on behalf of an original signer, but only the designated verifier can verify the validity of the proxy signature. In this paper, we first define the security requirements for strong designated verifier proxy signature schemes. And then we construct an identity-based strong designated verifier proxy signature scheme. We argue that the proposed scheme satisfies all of the security requirements.
文摘Hafizul Islam SK和G.P.Biswas最近基于椭圆曲线双线性对提出一个无证书强指定验证者签名方案,并声称该方案在三类敌手攻击模型下是可证明安全的,即第一类只得到系统公开参数和公钥的敌手,第二类可替换签名和验证者公钥的敌手,第三类可得到系统主密钥的敌手。分析该强指定验证者签名方案不能抵抗第三类敌手的攻击,亦即第三类敌手可以伪造有效的签名。针对此缺陷,对该无证书强指定验证者签名方案做了改进,在改进方案中,验证者的秘密私钥(由参与者独立产生的私钥)参与签名的验证计算,因此有效避免了原有方案的安全缺陷。最后对改进方案作了安全性分析,说明改进方案确实能抵抗三类敌手的攻击。
文摘In this paper an encryption-decryption algorithm based on two moduli is described: one in the real field of integers and another in the field of complex integers. Also the proper selection of cryptographic system parameters is described. Several numeric illustrations explain step-by-step how to precondition a plaintext, how to select secret control parameters, how to ensure feasibility of all private keys and how to avoid ambiguity in the process of information recovery. The proposed cryptographic system is faster than most of known public key cryptosystems, since it requires a small number of multiplications and additions, and does not require exponentiations for its implementation.
文摘Prime integers and their generalizations play important roles in protocols for secure transmission of information via open channels of telecommunication networks. Generation of multidigit large primes in the design stage of a cryptographic system is a formidable task. Fermat primality checking is one of the simplest of all tests. Unfortunately, there are composite integers (called Carmichael numbers) that are not detectable by the Fermat test. In this paper we consider modular arithmetic based on complex integers;and provide several tests that verify the primality of real integers. Although the new tests detect most Carmichael numbers, there are a small percentage of them that escape these tests.
