Brown University

Emc IP Holding Company LLC

Emc Corporation

Boston University

Charalampos Papamanthou

Roberto Tamassia

Nikolaos Triandopoulos

Michael Truman Goodrich

Dimitrios Papadopoulos

Cristina Videira Lopes

Charles Christopher Erway

Edward Joseph Tremel

Alptekin Küpçü

Duy Nguyen

Olga Ohrimenko

Alptekin Kupcu

Methods and apparatus are provided for authenticated pattern matching and authenticated exact path queries on outsourced data by a third party server. A source of the outsourced data computes verification information for node and suffix accumulators and sends the data, accumulation values and suffix tree or label trie information to the server; and publishes its public key and the verification digests. The verification may comprise an accumulation tree (AT) or any other public key authentication scheme, such as digital signatures, Merkle Trees and publishing the accumulation values. The server receives the query from a client and the server computes an answer &#x3b1; to the query and a verification proof that are provided to the client. The client then verifies the answer.

Authenticated pattern matching and exact path queries

An improved search engine technique allows a user to ensure that an untrusted search engine provides complete and correct search results without requiring large proofs for large data collections. Thus techniques are presented for a trusted crawler to index a distributed collection of documents and create an authenticated search structure that allows an untrusted search server to return reliably complete and correct search results.

Techniques for verifying search results over a distributed collection

In one exemplary embodiment, an apparatus includes a memory storing data and a processor performing operations. The apparatus generates or maintains an accumulation tree for the stored data&#x2014;an ordered tree structure with a root node, leaf nodes and internal nodes. Each leaf node corresponds to a portion of the data. A depth of the tree remains constant. A bound on a degree of each internal node is a function of a number of leaf nodes of a subtree rooted at the internal node. Each node of the tree has an accumulation value. Accumulation values of the root and internal nodes are determined by hierarchically employing an accumulator over the accumulation values of the nodes lying one level below the node in question. The accumulation value of the root node is a digest for the tree.

Cryptographic accumulators for authenticated hash tables

In one exemplary embodiment, a method includes: storing data for a file, organized as blocks, each having a portion of the file; and maintaining a skip list for the data. The skip list is an ordered tree structure having a root node, internal nodes and leaf nodes. Each leaf node corresponds to a block. Each node has a rank value corresponding to size of a subtree rooted at the node. The skip list employs a hashing scheme. The hash value of the root node and internal nodes is computed from a level of the node, the rank value and an interval between the node and another linked node to the right of or below the node. The hash value of the leaf nodes is computed from a level of the node, the rank value and an interval associated with the node.

Apparatus, methods, and computer program products providing dynamic provable data possession

A system and method for cryptographically checking the correctness of outsourced set operations performed by an untrusted server over a dynamic collection of sets that are owned (and updated) by a trusted source is disclosed. The system and method provides new authentication mechanisms that allow any entity to publicly verify a proof attesting the correctness of primitive set operations such as intersection, union, subset and set difference. Based on a novel extension of the security properties of bilinear-map accumulators as well as on a primitive called accumulation tree, the system and method achieves optimal verification and proof complexity, as well as optimal update complexity, while incurring no extra asymptotic space overhead. The method provides an efficient proof construction, adding a logarithmic overhead to the computation of the answer of a set-operation query. Applications of interest include efficient verification of keyword search and database queries.

System and method for optimal verification of operations on dynamic sets

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Berkeley, CA, United States of America

Charalampos Papamanthou