Abstract: Through the analysis of a forward secure threshold proxy signature scheme with designated verifier, it shows that even valid proxy signature could not be verified, because the scheme’s signature verification equation is wrong, and the scheme does not have the feature of anonymity. In order to deal with these disadvantages, an improved forward secure threshold proxy signature scheme is proposed. By updating the partial keys to achieve success in updating the collection members’ signing secret key, which makes it nearly impossible that no single member is expected to control the updating of the signing secret key. The new scheme has the feature of verifiability as well as anonymity.

Key words: forward secure, designated verifier, threshold proxy, anonymity

摘要： 首先通过分析崔涛等人提出的前向安全的指定验证者门限代理签名方案，以下简称C-L-W方案，发现该方案的签名验证等式是错误的，即使是合法的代理签名也无法通过指定验证者的验证，且方案不具有匿名性。之后提出了一个改进的前向安全的指定验证者门限代理签名方案，方案中签名密钥的前向更新是由部分密钥的前向更新实现的，使得方案中任何成员不能单独控制签名密钥的前向更新，方案不仅满足可验证性而且满足匿名性。

关键词: 前向安全, 指定验证者, 门限代理, 匿名性