  In some cases, the original signer may delegate its signing power to a
specified proxy group while ensuring individual accountability of each
participantsigner. The proxy signature scheme that achieves such purpose is
called the multi-proxy signature scheme and the signature generated by the
specified proxy group is called multi-proxy signature for the original signer.
Recently such scheme has been discussed by Lin et al. Lins scheme is based on
partial delegation by Mambo et al. In present chapter we introduce a new
multi-proxy signature scheme, which requires less computational overhead in
comparison to Lin et al, and also fulfill the requirement of partial delegation
with warrant simultaneously.
