Group signatures allow any member of a potentially large group to sign on behalf of the group. Group signatures are anonymous
and unlinkable for everyone with the exception of a designated group manager who can co-relate signatures and reveal the identity
of the acp- tual signer. At the same time, no one (including a group manager) can misattribute a valid group signature. Group
signatures are claimed to have many practical applications in e-commerce as well as in military and legal fields.
Despite some interesting and eclectic results, group signatures remain confined to academic literature. The focus of this
paper is two-fold. First, it discusses certain issues that stand in the way of practical applications of group signatures
and uses the example of on recent group signature scheme to illustrate certain problems. Second, this paper (informally) introduces
some practical security services that can be constructed us- ing any group signature scheme. Sample realizations of these
services are provided.
Keywords Public-key Cryptography - Digital Signatures - Group Signatures - Multi-Group Signatures - Sub-Group Signatures - Coalition Attacks - Revocation