International Association for Cryptologic Research (IACR)
Abstract
We construct the first fully collusion resistant tracing traitors
system with sublinear size ciphertexts and constant size private keys.
More precisely, let N be the total number of users. Our system
generates ciphertexts of size O(N) and private keys of size
O(1). We build our system by first building a simpler primitive
called private linear broadcast encryption (PLBE). We then show
that any PLBE gives a tracing traitors system with the same
parameters. Our system uses bilinear maps in groups of composite
order