Fair Traceable Multi-Group Signatures
V. Benjumea, S.G. Choi, J. Lopez, and M. Yung.
This paper presents fair traceable multi-group signatures (FTMGS),
which have enhanced capabilities, compared to group and traceable
signatures, that are important in real world scenarios combining
accountability and anonymity. The main goal of the primitive is to
allow multiple groups that are managed separately (managers are not even
aware of the other ones), yet allowing users (in the spirit of the
Identity 2.0 initiative) to manage what they reveal about their
identity with respect to these groups by themselves.
This new primitive incorporates the following additional features.
We specify the notion and implement it in the random oracle model.
While considering multiple groups it discourages users from
sharing their private membership keys through two orthogonal and
complementary approaches. In fact, it merges functionality similar to
credential systems with anonymous type of signing with revocation.
The group manager now mainly manages joining procedures,
and new entities (called fairness authorities and consisting of
various representatives, possibly) are involved in opening
and revealing procedures. In many systems scenario assuring fairness
in anonymity revocation is required.
Keywords: digital signatures, group signatures,
traceable signatures, anonymous authentication