This study deals with the dynamic property of threshold cryptosystem. A dynamic threshold cryptosystem allows the sender to choose the authorized decryption group and the threshold value for each message dynamically. ...This study deals with the dynamic property of threshold cryptosystem. A dynamic threshold cryptosystem allows the sender to choose the authorized decryption group and the threshold value for each message dynamically. We first introduce an identity based dynamic threshold cryptosystem, and then use the CanettiHalevi-Katz(CHK) transformation to transform it into a fully secure system in the traditional public key setting.Finally, the elegant dual system encryption technique is applied to constructing a fully secure dynamic threshold cryptosystem with adaptive security.展开更多
The short secret key characteristic of elliptic curve cryptosystem （ECC） are integrated with the （ t, n ） threshold method to create a practical threshold group signature scheme characterized by simultaneous signi...The short secret key characteristic of elliptic curve cryptosystem （ECC） are integrated with the （ t, n ） threshold method to create a practical threshold group signature scheme characterized by simultaneous signing. The scheme not only meets the requirements of anonymity and traceability of group signature but also can withstand Tseng and Wang＇s conspiracy attack. It allows the group manager to add new members and delete old members according to actual application, while the system parameters have a little change. Cryptanalysis result shows that the scheme is efficient and secure.展开更多
为提高Baek-Zheng方案的解密效率,用逆运算代替Baek-Zheng方案中所用的点乘运算设计验证过程.由于验证过程只需1次Pairing操作,故在保持Baek-Zheng方案的加密速度以及密文和解密碎片的长度的前提下,新方案将每个门限解密参与者的效率提...为提高Baek-Zheng方案的解密效率,用逆运算代替Baek-Zheng方案中所用的点乘运算设计验证过程.由于验证过程只需1次Pairing操作,故在保持Baek-Zheng方案的加密速度以及密文和解密碎片的长度的前提下,新方案将每个门限解密参与者的效率提高了近1倍.新方案在O rac le D iffie-Hellm an假设下被证明可以抗选择密文攻击.展开更多
基金the National Natural Science Foundation of China(Nos.61202023,60903189 and 61133014)
文摘This study deals with the dynamic property of threshold cryptosystem. A dynamic threshold cryptosystem allows the sender to choose the authorized decryption group and the threshold value for each message dynamically. We first introduce an identity based dynamic threshold cryptosystem, and then use the CanettiHalevi-Katz(CHK) transformation to transform it into a fully secure system in the traditional public key setting.Finally, the elegant dual system encryption technique is applied to constructing a fully secure dynamic threshold cryptosystem with adaptive security.
基金The National Natural Science Foundation of China (No60403027)
文摘The short secret key characteristic of elliptic curve cryptosystem （ECC） are integrated with the （ t, n ） threshold method to create a practical threshold group signature scheme characterized by simultaneous signing. The scheme not only meets the requirements of anonymity and traceability of group signature but also can withstand Tseng and Wang＇s conspiracy attack. It allows the group manager to add new members and delete old members according to actual application, while the system parameters have a little change. Cryptanalysis result shows that the scheme is efficient and secure.
文摘为提高Baek-Zheng方案的解密效率,用逆运算代替Baek-Zheng方案中所用的点乘运算设计验证过程.由于验证过程只需1次Pairing操作,故在保持Baek-Zheng方案的加密速度以及密文和解密碎片的长度的前提下,新方案将每个门限解密参与者的效率提高了近1倍.新方案在O rac le D iffie-Hellm an假设下被证明可以抗选择密文攻击.
