CAJ | 학술논문

近年来,为了解决身份基密码系统中固有的密钥托管问题,无证书公钥密码系统的概念被提出.对潘帅(2013)等提出的无证书签名方案进行安全性分析,指出该方案存在着公钥替换攻击和恶意KGC攻击,并给出具体攻击方法.针对上述问题,文中采用改变传统无证书签名算法顺序,定期更新用户秘密值来对原方案进行改进.改进方案同时加强了用户身份信息与其他参数的关联程度,以达到安全性要求.并基于离散对数问题、CDH问题和Inv-CDH问题的困难性假设,在随机预言模型中证明了改进方案的安全性.与潘方案比较,发现改进后的签名方案在整体性能上有更高的优势,且具有了前向安全性.
근년래,위료해결신빈기밀마계통중고유적밀약탁관문제,무증서공약밀마계통적개념피제출.대반수(2013)등제출적무증서첨명방안진행안전성분석,지출해방안존재착공약체환공격화악의KGC공격,병급출구체공격방법.침대상술문제,문중채용개변전통무증서첨명산법순서,정기경신용호비밀치래대원방안진행개진.개진방안동시가강료용호신빈신식여기타삼수적관련정도,이체도안전성요구.병기우리산대수문제、CDH문제화Inv-CDH문제적곤난성가설,재수궤예언모형중증명료개진방안적안전성.여반방안비교,발현개진후적첨명방안재정체성능상유경고적우세,차구유료전향안전성.
Recently,in order to eliminate the key-escrow problem in identity based cryptography,the notion of certificateless public key cryptography was proposed. Security analysis is carried out for the certificateless signature scheme presented by Pan et al,which shows that the scheme is insecure against public key replacement attack and malicious KGC attack. Detailed attack method is given. Aiming at these problem,the scheme is improved by the modification of traditional certificateless signature algorithm sequence and regularly update of user' s secret values in this paper. And the improved scheme also enhances the relationship between identity information with other pa-rameters to meet the security requirements. Its security relies on the hardness of the DL problem,CDH problem and Inverse-CDH prob-lem. Under the random oracle model,the new scheme is proved to be secure. Furthermore,it has better overall performances and forward security than the scheme presented by Pan et al.