Protecting Cryptographic Keys: The Trace
and Revoke Approach
Dalit Naor Moni Naor
The problem of protecting ownership of digital content has become a target
for many cryptographic studies in the past decade. These studies provide myriad
technology solutions to attack the problem, both from the aspect of rights
management and for piracy prevention. In this article we survey a number
of relevant techniques, focusing on methods for protecting cryptographic
keys and in particular for sending encrypted information to a group of
users. We present two such methods: the LKH method that is best tailored
to scenarios where attentiveness is guaranteed and the Subset-difference scheme
that is suited for the stateless case, where users are not necessarily always
on-line. The latter is a trace and revoke scheme that allows the detection
of keys which are used in a pirate box and, furthermore, can be used to
prevent these illegally used keys from decrypting future content.
We comment on the applications of these technological solutions to the ``real"
Related On-Line Papers:
- Cynthia Dwork, Jeff Lotspiech and Moni Naor, Digital Signets:
Self-Enforcing Protection of Digital Information,
- Amos Fiat and Moni Naor, Broadcast Encryption,
- Dalit Naor, Moni Naor and Jeff Lotspiech, Revocation and
Tracing Schemes for Stateless
- Benny Chor, Amos Fiat, Moni Naor and Benny Pinkas,
Tracing Traitors, IEEE Transactions on Information Theory, Vol.
46(3), pp. 893-910, 2000.
- Moni Naor and Benny Pinkas, Threshold Traitor Tracing, Crypto 98.
- Moni Naor and Benny Pinkas, Efficient Trace and Revoke Schemes, FC'2000.
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