Anonymous proxy signature scheme can provide the privacy protection for the proxy signer. Recently, Yu et al. proposed an anonymous proxy signature, which can be viewed as the organic combination of proxy signature an...Anonymous proxy signature scheme can provide the privacy protection for the proxy signer. Recently, Yu et al. proposed an anonymous proxy signature, which can be viewed as the organic combination of proxy signature and ring signature. However, the efficiency is low. In this paper, we propose an efficient and secure proxy signature with the properties of anonymity and traceability, and it is provably secure in the random oracle model. Compared with Yu et al.＇s scheme, the scheme has higher efficiency.展开更多
区块链因具有分布式、不可篡改和不变性的特点而广受关注,但区块链中使用的国际密码算法存在一定的后门安全隐患。现基于国密算法SM2,结合无证书密码机制,提出了一种基于区块链的无证书公钥加密(Certificateless Public Key Encryption,...区块链因具有分布式、不可篡改和不变性的特点而广受关注,但区块链中使用的国际密码算法存在一定的后门安全隐患。现基于国密算法SM2,结合无证书密码机制,提出了一种基于区块链的无证书公钥加密(Certificateless Public Key Encryption,CL-PKE)方案。该方案不依赖双线性配对,降低了计算成本,消除了证书管理和密钥托管问题,并且利用区块链不可篡改和可追溯的优点,实现了用户对公钥的更新与撤销,同时能够对抗无证书机制中的Type-1和Type-2型敌手。该方案基于计算性Diffie-Hellman问题(Computational Diffie-Hellman Problem,CDHP)的困难性,在随机预言模型中被证明在自适应选择密文攻击下具有不可区分性。最后进行性能分析与测试,结果表明,与现有CL-PKE方案相比,该方案的计算效率至少提升11%。展开更多
共识机制是区块链系统的核心技术,但是目前的共识机制存在3个问题,即共识效率低、可靠性和安全性低、计算复杂度高。针对这些问题,提出了一种新的子分组多重Schnorr签名方案,该方案既拥有Schnorr数字签名密码体制的计算复杂度低优势,又...共识机制是区块链系统的核心技术,但是目前的共识机制存在3个问题,即共识效率低、可靠性和安全性低、计算复杂度高。针对这些问题,提出了一种新的子分组多重Schnorr签名方案,该方案既拥有Schnorr数字签名密码体制的计算复杂度低优势,又拥有子分组多重签名的优势(它可以从集合的全体成员中选择不定数量的成员组成子分组,以代替群组产生多重签名,由于子分组是不可预知的,因此可以有效避免出现Byzantine叛徒,提高了方案的安全性,解决了共识机制存在的可靠性和安全性低、计算复杂度高的问题)。该方案引入了公共第三方(PTP,public third party),PTP由可自动公开执行的智能合约充当,完全公开透明,不仅可以抵御流氓密钥攻击,还减少了签名过程的总通信轮次和时间开销,解决了共识机制存在的共识效率低问题。同时,详细证明了该方案具有鲁棒性,可以提高共识机制的安全性;基于离散对数假设,该方案在随机预言模型下具有不可伪造性。理论分析和实验结果证明,该方案拥有更小的公钥长度、私钥长度、单签名长度和多重签名长度,拥有更少的通信轮次,签名生成算法和验证签名算法的时间开销更小,应用在共识机制上具有更优越的性能。展开更多
The research on the identification scheme is an important and active area in computer and communication security. A series of identification schemes were proposed to improve the efficiency and security of the protocol...The research on the identification scheme is an important and active area in computer and communication security. A series of identification schemes were proposed to improve the efficiency and security of the protocols by various methods. Based on the hardness assumption of the discrete logarithm problem in a gap Diffie-Hellman group and the difficulty of the collusion attack algorithm with k traitors, an efficient identification scheme is presented. Without random oracle models, the proposed scheme is then proved secure against impersonation and reset attacks in both concurrent and reset attack setting. Since the proposed scheme is simple, memory-saving, computation-efficient, and perfectly-secure, it is well suitable for use in smart cards.展开更多
This paper focuses on the instantiation of random oracles in public key encryption schemes. A misunderstanding in the former instantiations is pointed out and analyzed. A method of using this primitive as a substituti...This paper focuses on the instantiation of random oracles in public key encryption schemes. A misunderstanding in the former instantiations is pointed out and analyzed. A method of using this primitive as a substitution of random oracles is also proposed. The partial and full instantiations of random oracles in optimal asymmetric encryption padding （OAEP） implemented by pseudorandom functions are described and the resulted schemes are proven to be indistinguishable secure against adaptive chosen ciphertext attack （IND-CCA2） secure. Using this method, one can transform a practical public key encryption scheme secure in the random oracle model into a standard-model secure scheme. The security of the scheme is based on computational assumptions, which is weaker than decisional assumptions used in Cramer- Shoup like schemes.展开更多
基金supported by the National Natural Science Foundation of China (61121061, 90812001, 61272519)
文摘Anonymous proxy signature scheme can provide the privacy protection for the proxy signer. Recently, Yu et al. proposed an anonymous proxy signature, which can be viewed as the organic combination of proxy signature and ring signature. However, the efficiency is low. In this paper, we propose an efficient and secure proxy signature with the properties of anonymity and traceability, and it is provably secure in the random oracle model. Compared with Yu et al.＇s scheme, the scheme has higher efficiency.
文摘共识机制是区块链系统的核心技术,但是目前的共识机制存在3个问题,即共识效率低、可靠性和安全性低、计算复杂度高。针对这些问题,提出了一种新的子分组多重Schnorr签名方案,该方案既拥有Schnorr数字签名密码体制的计算复杂度低优势,又拥有子分组多重签名的优势(它可以从集合的全体成员中选择不定数量的成员组成子分组,以代替群组产生多重签名,由于子分组是不可预知的,因此可以有效避免出现Byzantine叛徒,提高了方案的安全性,解决了共识机制存在的可靠性和安全性低、计算复杂度高的问题)。该方案引入了公共第三方(PTP,public third party),PTP由可自动公开执行的智能合约充当,完全公开透明,不仅可以抵御流氓密钥攻击,还减少了签名过程的总通信轮次和时间开销,解决了共识机制存在的共识效率低问题。同时,详细证明了该方案具有鲁棒性,可以提高共识机制的安全性;基于离散对数假设,该方案在随机预言模型下具有不可伪造性。理论分析和实验结果证明,该方案拥有更小的公钥长度、私钥长度、单签名长度和多重签名长度,拥有更少的通信轮次,签名生成算法和验证签名算法的时间开销更小,应用在共识机制上具有更优越的性能。
基金supported by the National Natural Science Foundation of China (60803151)the Major Joint Research Foundation of NSFC and Guangdong Province (U0835004).
文摘The research on the identification scheme is an important and active area in computer and communication security. A series of identification schemes were proposed to improve the efficiency and security of the protocols by various methods. Based on the hardness assumption of the discrete logarithm problem in a gap Diffie-Hellman group and the difficulty of the collusion attack algorithm with k traitors, an efficient identification scheme is presented. Without random oracle models, the proposed scheme is then proved secure against impersonation and reset attacks in both concurrent and reset attack setting. Since the proposed scheme is simple, memory-saving, computation-efficient, and perfectly-secure, it is well suitable for use in smart cards.
基金Supported by the National Basic Research Program of China (973 Program) (2007CB311201)the National High-Technology Research and Development Program of China (863 Program) (2006AA01Z427)the National Natural Science Foundation of China (60673073)
文摘This paper focuses on the instantiation of random oracles in public key encryption schemes. A misunderstanding in the former instantiations is pointed out and analyzed. A method of using this primitive as a substitution of random oracles is also proposed. The partial and full instantiations of random oracles in optimal asymmetric encryption padding （OAEP） implemented by pseudorandom functions are described and the resulted schemes are proven to be indistinguishable secure against adaptive chosen ciphertext attack （IND-CCA2） secure. Using this method, one can transform a practical public key encryption scheme secure in the random oracle model into a standard-model secure scheme. The security of the scheme is based on computational assumptions, which is weaker than decisional assumptions used in Cramer- Shoup like schemes.
