Cryptology ePrint Archive: Report 2015/1010
TWORAM: Round-Optimal Oblivious RAM with Applications to Searchable Encryption
Sanjam Garg and Payman Mohassel and Charalampos Papamanthou
Abstract: We present TWORAM, the first efficient round-optimal oblivious RAM (ORAM) scheme. TWORAM provides oblivious access of a memory index $y$ in exactly two rounds: The client prepares an encrypted query encapsulating $y$ and sends it to the server. The server accesses memory obliviously and returns encrypted information containing the desired value $\mathsf{M}[y]$. The cost of TWORAM is only a multiplicative factor of security parameter higher than the tree-based ORAM schemes such as the path ORAM of Stefanov et al. (CCS, 2013). TWORAM gives rise to interesting applications, and in particular to the first fully-secure searchable symmetric encryption scheme where search is sublinear and search pattern is not leaked---access pattern can also be concealed if we assume the documents are stored in the obliviously accessed memory $\mathsf{M}$.
Category / Keywords: secret-key cryptography / Searchable Symmetric Encryption, Oblivious RAM
Date: received 16 Oct 2015, last revised 19 Feb 2016
Contact author: sanjamg at berkeley edu, payman mohassel@gmail com, cpap@umd edu
Available format(s): PDF | BibTeX Citation
Version: 20160219:205323 (All versions of this report)
Short URL: ia.cr/2015/1010
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