Message-Locked Encryption for Lock-Dependent Messages
- Martín AbadiAffiliated withMicrosoft Research Silicon ValleyUniversity of California, Santa Cruz
- , Dan BonehAffiliated withStanford University
- , Ilya MironovAffiliated withMicrosoft Research Silicon Valley
- , Ananth RaghunathanAffiliated withStanford University
- , Gil SegevAffiliated withStanford University
Motivated by the problem of avoiding duplication in storage systems, Bellare, Keelveedhi, and Ristenpart have recently put forward the notion of Message-Locked Encryption (MLE) schemes which subsumes convergent encryption and its variants. Such schemes do not rely on permanent secret keys, but rather encrypt messages using keys derived from the messages themselves.
We strengthen the notions of security proposed by Bellare et al. by considering plaintext distributions that may depend on the public parameters of the schemes. We refer to such inputs as lock-dependent messages. We construct two schemes that satisfy our new notions of security for message-locked encryption with lock-dependent messages.
Our main construction deviates from the approach of Bellare et al. by avoiding the use of ciphertext components derived deterministically from the messages. We design a fully randomized scheme that supports an equality-testing algorithm defined on the ciphertexts.
Our second construction has a deterministic ciphertext component that enables more efficient equality testing. Security for lock-dependent messages still holds under computational assumptions on the message distributions produced by the attacker.
In both of our schemes the overhead in the length of the ciphertext is only additive and independent of the message length.
KeywordsDeduplication convergent encryption message-locked encryption
- Message-Locked Encryption for Lock-Dependent Messages
- Book Title
- Advances in Cryptology – CRYPTO 2013
- Book Subtitle
- 33rd Annual Cryptology Conference, Santa Barbara, CA, USA, August 18-22, 2013. Proceedings, Part I
- pp 374-391
- 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
- Additional Links
- convergent encryption
- message-locked encryption
- Industry Sectors
- eBook Packages
- Editor Affiliations
- 16. Boston University and Tel Aviv University
- 17. AT&T Labs – Research
- Author Affiliations
- 18. Microsoft Research Silicon Valley, USA
- 20. University of California, Santa Cruz, USA
- 19. Stanford University, USA
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