An application of ramp schemes to broadcast encryption

Broadcast encryption schemes were first introduced by Fiat and Naor and hav e been studied by several authors. The scheme of Fiat and Naor was generali zed by Stinson, who proposed the so-called "KIO construction". In this cons truction, a threshold scheme is used to divide the secret into pieces calle d shares. In this note, we instead use a ramp scheme, which allows the info rmation rates of the broadcast encryption scheme to be improved significant ly. (C) 1999 Elsevier Science B.V. All rights reserved.