Efficient Trace and  Revoke Schemes

Abstract:

1. (1) deter users from leaking their personal keys
2. (2) trace which users leaked keys to construct an illegal decryption device
3. (3) revoke these keys as to render the device dysfunctional.

We start by designing an efficient revocation scheme,  based on secret sharing.  It can remove up to t parties and is secure against coalitions of size t. The performance of this scheme is more efficient than that of previously proposed schemes with the same properties. We then show how to combine the revocation scheme with traitor tracing and self enforcement schemes. More precisely, how to construct schemes such that

1. (1) Each user's personal key contains some sensitive information of that user (e.g., the user's credit card number), and therefore users would be reluctant o disclose their keys.
2. (2) An illegal decryption device discloses the identity of users that contributed keys to construct the device.
3. (3) it is possible to revoke the keys of corrupt users. For this point it is important to be able to do so without publicly disclosing the sensitive information.

Postscript, gzipped Postscript.

Related On-Line Papers:
 

• Cynthia Dwork, Jeff Lotspiech and Moni Naor, Digital Signets: Self-Enforcing Protection of Digital Information, Abstract , Postscript, gzipped Postscript
• Amos Fiat and Moni Naor, Broadcast Encryption, Abstract, Postscript, gzipped Postscript
• Dalit Naor, Moni Naor and Jeff Lotspiech, Revocation and Tracing Schemes for Stateless Receivers, Abstract, Postscript, gzipped Postscript
• Moni Naor and Benny Pinkas, Threshold Traitor Tracing, Crypto 98. Postscript, gzipped Postscript

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