Abstract: Described herein is an efficient, dynamic Symmetric Searchable Encryption (SSE) scheme. A client computing device includes a plurality of files and a dictionary of keywords. An index is generated that indicates, for each keyword and each file, whether a file includes a respective keyword. The index is encrypted and transmitted (with encryptions of the files) to a remote repository. The index is dynamically updateable at the remote repository, and can be utilized to search for files that include keywords in the dictionary without providing the remote repository with information that identifies content of the file or the keyword.

Abstract: 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 ? to the query and a verification proof that are provided to the client. The client then verifies the answer.

Abstract: Certain embodiments of the present invention involve a method of storing an erasure coded copy of block data, and storing newly updated block data into a separate erasure-coded log structure. The method also includes auditing both the erasure copy of block data and the newly updated block data. The erasure copy of block data and the newly updated block data are probabilistically checked during the audit. In certain other embodiments the newly updated block data is stored in a log structure.

Abstract: Certain embodiments of the present invention involve a method of storing an erasure coded copy of block data, and storing newly updated block data into a separate erasure-coded log structure. The method also includes auditing both the erasure copy of block data and the newly updated block data. The erasure copy of block data and the newly updated block data are probabilistically checked during the audit. In certain other embodiments the newly updated block data is stored in a log structure.

Abstract: 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.

Abstract: 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—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.

Abstract: Described herein is an efficient, dynamic Symmetric Searchable Encryption (SSE) scheme. A client computing device includes a plurality of files and a dictionary of keywords. An index is generated that indicates, for each keyword and each file, whether a file includes a respective keyword. The index is encrypted and transmitted (with encryptions of the files) to a remote repository. The index is dynamically updateable at the remote repository, and can be utilized to search for files that include keywords in the dictionary without providing the remote repository with information that identifies content of the file or the keyword.

Abstract: 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.

Abstract: Described herein is an efficient, dynamic Symmetric Searchable Encryption (SSE) scheme. A client computing device includes a plurality of files and a dictionary of keywords. An index is generated that indicates, for each keyword and each file, whether a file includes a respective keyword. The index is encrypted and transmitted (with encryptions of the files) to a remote repository. The index is dynamically updateable at the remote repository, and can be utilized to search for files that include keywords in the dictionary without providing the remote repository with information that identifies content of the file or the keyword.

Abstract: 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—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.

Abstract: 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—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.

Abstract: 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.

Abstract: 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.

Abstract: Described herein is an efficient, dynamic Symmetric Searchable Encryption (SSE) scheme. A client computing device includes a plurality of files and a dictionary of keywords. An index is generated that indicates, for each keyword and each file, whether a file includes a respective keyword. The index is encrypted and transmitted (with encryptions of the files) to a remote repository. The index is dynamically updateable at the remote repository, and can be utilized to search for files that include keywords in the dictionary without providing the remote repository with information that identifies content of the file or the keyword.

Abstract: 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.

Abstract: 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—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.