  A first multi-proxy multi-signcryption scheme from pairings, which
efficiently combines a multi-proxy multi-signature scheme with a signcryption,
is proposed. Its security is analyzed in detail. In our scheme, a proxy
signcrypter group could be authorized as a proxy agent by the cooperation of
all members in the original signcrypter group. Then the proxy signcryptions can
be generated by the cooperation of all the signcrypters in the authorized proxy
signcrypter group on behalf of the original signcrypter group. The correctness
and the security of this scheme are proved.
