Anonymous Attribute Certificates based on Traceable Signatures
V. Benjumea, J. Lopez, and J. M. Troya.
Anonymous attribute certificates were introduced by Benjumea
et. al in PKC'04 in order to integrate anonymity
capabilities in the standardized X.509 attribute certificates. That
solution was based on the use of fair-blind signatures, but did not
explore further possibilities of constructing similar data structures
based on more advanced signature schemes. In this paper, we propose a
new type of anonymous attribute certificates that is based on the
recently proposed traceable signature
scheme by Kiayias et al. in Eurocrypt'04, providing a new anonymous
authorization solution with interesting features that were not covered
with the aforementioned solution. Thus, this new solution allows users
to make use of their attribute certificates in an anonymous way, but
under certain circumstances it allows to disclose the users'
identities, trace the transactions carried out by any specific user,
or revoke any anonymous attribute certificate. An additional
contribution of this work is that it pays special attention to the
preservation of the unlinkability property between transactions,
making impossible the creation of anonymous user profiles.
Keywords: authorization, privilege, anonymity, credential