Dynamic Credentials and Ciphertext Delegation for Attribute-Based Encryption
- Amit SahaiAffiliated withDepartment of Computer Science, UCLA
- , Hakan SeyaliogluAffiliated withDepartment of Mathematics, UCLA
- , Brent WatersAffiliated withDepartment of Computer Science, University of Texas at Austin
We first ask how a third party who is not trusted with secret key information can process a ciphertext to disqualify revoked users from decrypting data encrypted in the past. Our core tool is a new procedure called ciphertext delegation that allows a ciphertext to be ‘re-encrypted’ to a more restrictive policy using only public information.
Second, we study the problem of revocable attribute-based encryption. We provide the first fully secure construction by modifying an attribute-based encryption scheme due to Lewko et al.  and prove security in the standard model.
We then combine these two results for a new approach for revocation on stored data. Our scheme allows a storage server to update stored ciphertexts to disqualify revoked users from accessing data that was encrypted before the user’s access was revoked while key update broadcasts can dynamically revoke selected users.
- Dynamic Credentials and Ciphertext Delegation for Attribute-Based Encryption
- Book Title
- Advances in Cryptology – CRYPTO 2012
- Book Subtitle
- 32nd Annual Cryptology Conference, Santa Barbara, CA, USA, August 19-23, 2012. Proceedings
- pp 199-217
- Print ISBN
- Online ISBN
- Series Title
- Lecture Notes in Computer Science
- Series Volume
- Series ISSN
- Springer Berlin Heidelberg
- Copyright Holder
- International Association for Cryptologic Research 2012
- Additional Links
- Industry Sectors
- eBook Packages
- Editor Affiliations
- 16. Department of Computer Science, University of Calgary
- 17. Department of Computer Science, University of Boston
- Author Affiliations
- 18. Department of Computer Science, UCLA, Los Angeles, USA
- 19. Department of Mathematics, UCLA, Los Angeles, USA
- 20. Department of Computer Science, University of Texas at Austin, Austin, USA
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