Cryptology ePrint Archive: Report 2009/295

Defending Against Key Abuse Attacks in KP-ABE Enabled Broadcast Systems

Shucheng Yu and Kui Ren and Wenjing Lou and Jin Li

Abstract: Key-Policy Attribute-Based Encryption (KP-ABE) is a promising cryptographic primitive which enables fine-grained access control over sensitive data. However, key abuse attacks in KP-ABE may impede its wide application especially in copyright-sensitive systems. To defend against this kind of attacks, this paper proposes a novel KP-ABE scheme which is able to disclose any illegal key distributorís ID when key abuse is detected. In our scheme, each bit of user ID is defined as an attribute and the user secret key is associated with his unique ID. The tracing algorithm fulfills its task by tricking the pirate device into decrypting the ciphertext associated with the corresponding bits of his ID. Our proposed scheme has the salient property of black box tracing, i.e., it traces back to the illegal key distributorís ID only by observing the pirate deviceís outputs on certain inputs. In addition, it does not require the pirate deviceís secret keys to be well-formed as compared to some previous work. Our proposed scheme is provably secure under the Decisional Bilinear Diffie-Hellman (DBDH) assumption and the Decisional Linear (DL) assumption.

Category / Keywords: public-key cryptography / attribute-based encryption, traitor tracing, broadcast

Publication Info: Accepted by securecomm 2009.

Date: received 18 Jun 2009, last revised 1 Jul 2009

Contact author: yscheng at wpi edu

Available format(s): PDF | BibTeX Citation

Note: This is the revised version to the previous one.

Version: 20090701:154901 (All versions of this report)

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