  This paper presents an identity based multi-proxy multi-signcryption scheme
from pairings. In this scheme a proxy signcrypter group could authorized as a
proxy agent by the coopration of all members in the original signcryption
group. Then the proxy signcryption can be generated by the cooperation of all
the signcrypters in the authorized proxy signcrypter group on the behalf of the
original signcrypter group. As compared to the scheme of Liu and Xiao, the
proposed scheme provides public verifiability of the signature along with
simplified key management.
