International Association
for Cryptologic Research

In this paper the ID-based signcryption scheme of Li, Xin, and Hu is extended to a compartmented scheme. If an organization is partitioned into different compartments, this scheme allows any member of a specific compartment to participate in the unsigncryption; moreover, each mem- ber of a compartment has information unique to that individual. This construction is the first (to the authors\' knowledge) to combine identity-based encryption, Shamir\'s threshold scheme, and signcryption into an implementable compartmented sharing scheme.