Abstract
We present a novel agent-based threshold proxy signcryption (ATPS) protocol, which enables an agent owner to securely delegate his signing capabilities to a mobile agent so that the mobile agent can sign documents on behalf of its owner. The protocol incorporates three novel contributions: a proxy key generation method, a threshold proxy signcryption scheme and a proxy signature verification method. The most notable feature of the protocol is that it enables a mobile agent to securely, efficiently and autonomously sign documents on the owner's behalf in a remote host with nonrepudiation and fairness assurance for both the owner and the remote host. The security of the proposed protocol is analyzed and its performance against other related work is evaluated.