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A SubscriberExcluding and TraitorTracing Broadcast Distribution System
Maki YOSHIDA Toru FUJIWARA
Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Vol.E84A
No.1
pp.247255 Publication Date: 2001/01/01
Online ISSN:
DOI:
Print ISSN: 09168508 Type of Manuscript: Special Section PAPER (Special Section on Cryptography and Information Security) Category: Keyword: broadcast distribution system, subscriberexcluding, pirate decoder, traitor tracing, ElGamal cryptosystem,
Full Text: PDF(250.5KB)>>
Summary:
A broadcast distribution system (BDS) is a system for the distribution of digital contents over broadcast channel where the data supplier broadcasts the contents in encrypted form and gives each subscriber a decoder containing a secret decryption key. A traitor is a subscriber who offers the information which allows to decrypt the broadcast. When a pirate decoder is captured, if at least one traitor can be identified from it, a BDS is said to be traitortracing. If the data supplier can prevent subscribers from obtaining the contents without recalling their decoders, a BDS is said to be subscriberexcluding. In this paper, we propose an efficient BDS which is both subscriberexcluding and traitortracing. We use similar mathematics to a threshold cryptosystem. In the proposed BDS, the maximum number of excluded subscribers reaches the maximum number of traitors in a coalition for which at least one traitor can be identified. We prove that the proposed BDS is secure against ciphertextonly attack if and only if ElGamal cryptosystem is secure against the attack and the discrete logarithm problem is hard. The proposed BDS is the first one which satisfies all the following features: Both subscriberexcluding and traitortracing, identifying all the traitors, black box tracing and public key system.

