Single Round-trip Hierarchical ORAM via Succinct Indices. (arXiv:2208.07489v2 [cs.CR] UPDATED)

Accesses to data stored remotely create a side channel that is known to leak
information even if the content is encrypted. Oblivious RAM is a cryptographic
primitive that provides confidentiality of access patterns in remote storage
settings. To outsource a database of $n$ blocks of $B$ bits, traditional
solutions restrict the client to $\mathcal{O}(B)$ bits of private memory. A
class of solutions, known as Hierarchical ORAM, has achieved theoretically
optimal bandwidth performance in this setting. Hierarchical ORAM distributes
data blocks …

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