采用新的支付方式 扩大我国产品出口：推荐使用O／A和备用信用证相结合的新

通过对赊销、跟单信用证、备用信用证、银行保函、国际保理服务等结算方式在国际贸易中对买卖双方产生的有利和不利影响的分析,得出结论：赊销和备用信用证相结合这一新的综合结算方式,对买卖双立都具有吸引力,在未来十年里,这种结算方式必将得到广泛的使用。     

基于RSA和DLP数字签名方案的分析和改进

以李发根提出的签名方案为例子,通过攻击发现了它的安全性存在漏洞,并针对它的安全漏洞提出了一种改进的签名方案。该方案同样是基于RSA和DLP两大困难问题,同时修复了李的方案中存在的漏洞,并且步骤简单并且安全性可靠。通过4种方式的攻击对改进的方案进行安全性分析,证明了改进的方案在RSA和DLP问题不能同时求解的情况想是安全的。同时改进的方案计算步骤和复杂度上都优于Li的方案,信息通信量上低于Li的方案。     

A novel group signature with one time secret key

INTRODUCTION The concept of group signature, first introduced by Chaum and van Heyst (1992), allows each group member to sign messages on behalf of the group, and the receiver can use a group public key to verify the group signature, but cannot reveal the signer. In case of disputes, the group authority can open the group signature and identify the signer, but the outsider cannot identify all previous group signatures gener-ated by the same group member. A group member cannot impersonate…     

Colluding attacks on a group signature scheme

INTRODUCTION The concept of group signature,first introduced by Chaum and van Heyst(1992),allows each group member(and only the group member)to sign mes-sages on behalf of the group,and requires that the receiver can use a group public key to verify the group signature,but cannot reveal the signer.The group signature should be traceable,i.e.the group authority can open the group signature and identify the signer.The outsider cannot identify all previous group sig-natures generated by the …