关于无个人公钥的群认证

群认证是一种多方认证机制，研究动态群的成员们如何确认每个成员身份的真实性。这里，群组成员没有个人公钥。本文首先分析了Harn的群认证方案，证明他的方案在有意义的参数下是不安全的。我们还研究了群认证和几个多方签名之间的关系。我们证明基于身份的多重签名可以转换为安全群认证协议，而门限签名方案没有这种特性。我们还证明，如果去掉签名消息的话，Bellare和Neven的基于ID的多重签名方案实际上就是一个安全的群认证协议。

On Group Authentication without Personal Public-Keys

We study the group authentication, where a dynamic group of members wish to confirm whether all of them are valid. The restriction is that a member does not have a personal public key. We present an attack to Harn''s scheme, which implies that his scheme is insecure as long as the parameters are set to be meaningful. We also study the relation between a group authentication and some multi-party based signatures. We show that an ID-based multi-signature can be converted into a secure group authentication while a threshold signature scheme does not have this property. We also show that an ID-based multi-signature by Bellare and Neven in fact is a secure group authentication when we remove the message to be signed.