| Title | Updatable Block-Level Message-Locked Encryption |
| Publication Type | Conference Paper |
| Year of Publication | 2017 |
| Authors | Zhao, Yongjun, Chow, Sherman S.M. |
| Conference Name | Proceedings of the 2017 ACM on Asia Conference on Computer and Communications Security |
| Publisher | ACM |
| Conference Location | New York, NY, USA |
| ISBN Number | 978-1-4503-4944-4 |
| Keywords | composability, compositionality, incremental cryptography, Merkle-hash tree, message-locked encryption, Metrics, provable security, pubcrawl, random oracle model, resilience, Resiliency |
| Abstract | Deduplication is a widely used technique for reducing storage space of cloud service providers. Yet, it is unclear how to support deduplication of encrypted data securely until the study of Bellareetal on message-locked encryption (Eurocrypt 2013). Since then, there are many improvements such as strengthening its security, reducing client storage, etc. While updating a (shared) file is common, there is little attention on how to efficiently update large encrypted files in a remote storage with deduplication. To modify even a single bit, existing solutions require the trivial and expensive way of downloading and decrypting the large ciphertext. We initiate the study of updatable block-level message-locked encryption. We propose a provably secure construction that is efficiently updatable with O(logtextbarFtextbar) computational cost, where textbarFtextbar is the file size. It also supports proof-of-ownership, a nice feature which protects storage providers from being abused as a free content distribution network. |
| DOI | 10.1145/3052973.3053012 |
| Citation Key | zhao_updatable_2017 |
Updatable Block-Level Message-Locked Encryption