  In this paper, we propose a Directed threshold multisignature scheme without
SDC. This signature scheme is applicable when the message is sensitive to the
signature receiver; and the signatures are generated by the cooperation of a
number of people from a given group of senders. In this scheme, any malicious
set of signers cannot impersonate any other set of signers to forge the
signatures. In case of forgery, it is possible to trace the signing set.
