Abstract: A method for sharing read access to a document stored on memory hardware. The method includes receiving a shared read access command from a sharor sharing read access to a sharee for a document stored on memory hardware in communication with the data processing hardware, and receiving a shared read access request from the sharee. The shared read access command includes an encrypted value and a first cryptographic share value based on a write key, a read key, a document identifier, and a sharee identifier. The method also includes multiplying the first and second cryptographic share values to determine a cryptographic read access value. The cryptographic read access value authorizes read access to the sharee for the document. The method also includes storing a read access token for the sharee including the cryptographic read access value and the encrypted value in a user read set of the memory hardware.

Abstract: A method includes executing an instruction to execute a query for a data block, the data block associated with a corresponding memory level of a logarithmic number of memory levels (li) of memory, each memory level (li) including physical memory (RAMi) residing on memory hardware of a distributed system. The method also includes retrieving a value associated with the data block from an oblivious hash table using a corresponding key, and extracting un-queried key value pairs from the oblivious hash table associated with un-queried data blocks after executing a threshold number of queries for data blocks. The method also includes a multi-array shuffle routine on the extracted key value pairs from the oblivious hash table to generate an output array containing the un-queried key value pairs.

Abstract: Systems, methods, devices, and other techniques for preserving privacy when comparing private datasets from first and second computing systems. The second computing system identifies a first set of identifiers corresponding to records in a private database of the second computing system. The second computing system receives blinded versions of a set of identifiers corresponding to records in a private database of the first computing system. The second computing system determines an intersection or characteristic thereof of the records in the private database of the first computing system and the records in the private database of the second computing system based on matches between the blinded versions of the first and second sets of identifiers.

Abstract: Systems and methods may be used for establishing a link between user identifiers of different systems without disclosing specific user identifying information. One method includes generating a matching relationship based on double encrypted one or more first data sets of a first party system and double encrypted one or more second data sets of a second party system. The matching relationship indicates one or more links between match keys associated with the first party system and the match keys associated with the third party system. The method includes assigning bridge identifiers for user identifiers associated with the first party system and the user identifiers associated with the third party system based on the matching relationship.

Abstract: A method disclosed herein may include receiving, at a first computing system, encrypted identifiers and encrypted values, performing, by the first computing system, a concealing operation on the encrypted identifiers to produce concealed encrypted identifiers, wherein the concealing operation conceals the encrypted identifiers from the first computing system and a second computing system but enables matching between the concealed encrypted identifiers, decrypting, by the second computing system, the concealed encrypted identifiers to produce concealed identifiers, and performing, by the second computing system, an aggregation operation using the concealed identifiers and the encrypted values to produce an encrypted aggregate value without accessing personally identifiable information associated with the encrypted values.

Abstract: A method for providing an encrypted search system includes receiving a search query for a keyword that appears in one or more encrypted emails stored on an untrusted storage device and accessing, a count table to obtain a count of unique emails within the emails that include the keyword. The method also includes generating a delegatable pseudorandom function (DPRF) based on the keyword, a private cryptographic key, and the count of unique emails that include the keyword and delegating at least a portion of the DPRF to the untrusted storage device that causes the storage device to evaluate the delegated DPRF, access an encrypted search index associated with the emails, and determine one or more encrypted emails associated with the delegated DPRF based on the encrypted search index. The storage device also returns, to the user device, an identifier for each encrypted email associated with the delegated DPRF.

Abstract: A method includes obtaining a plaintext query that includes a sequence of plaintext integers and generating a polynomial having coefficients that include the sequence of plaintext integers of the plaintext query. The method also includes encrypting the polynomial using a secret encryption key and transmitting the encrypted polynomial to a server. The secret encryption key is randomly sampled from a ciphertext space and the server is configured to expand the encrypted polynomial using a public encryption key to obtain a sequence of encrypted integers corresponding to the sequence of plaintext integers. The method also includes receiving an encrypted result from the server. The encrypted result is based on the sequence of encrypted integers.

Abstract: A method for providing encrypted search includes receiving, at a user device associated with a user, a search query for a keyword that appears in one or more encrypted documents stored on an untrusted storage device and accessing a count table to obtain a count of documents that include the keyword. The method also includes generating a delegatable pseudorandom function (DPRF) based on the keyword, a private cryptographic key, and the count of documents. The method also includes evaluating a first portion of the DPRF and delegating a remaining second portion of the DPRF to the untrusted storage device which causes the untrusted storage device to evaluate the DPRF and access an encrypted search index associated with the documents. The untrusted storage device determines one or more encrypted documents associated with DPRF and returns, to the user device, an identifier for each encrypted document associated with the DPRF.

Abstract: A method including at each of a number of client devices receiving a data item, receiving a public key from a second computing system, encrypting the data item using the public key to produce a singly encrypted data item, engaging in an oblivious pseudorandom function protocol with a first computing system using the singly encrypted data item to produce a seed, generating an encrypted secret share using a threshold secret sharing function under which the encrypted secret share cannot be decrypted until a threshold number of encrypted secret shares associated with the same singly encrypted data item are received, and transmitting the encrypted secret share to the first computing system and at the first computing system receiving a number of encrypted secret shares from the number of client devices, processing the number of encrypted secret shares to produce processed data, and transmitting the processed data to a second computing system.

Abstract: A method for performing encrypted search includes receiving a search query for a plurality of keywords from a user device that appear in one or more encrypted documents stored on an untrusted storage device. The method also includes accessing an encrypted search index to obtain a first list of document identifiers each representative of a document that includes a first keyword and a second keyword of the plurality of keywords. The method also includes, for each remaining keyword, determining a corresponding list of document identifiers each representative of a document that includes the first, second, and respective remaining keyword. The method includes determining, based on the first list of document identifiers and each corresponding list of document identifiers, a second list of document identifiers each representative of a document that includes each of the plurality of keywords. The method also includes returning the second list to the user device.

Abstract: Systems and methods may be used for establishing a link between user identifiers of different systems without disclosing specific user identifying information. One method includes generating a matching relationship based on double encrypted one or more first data sets of a first party system and double encrypted one or more second data sets of a second party system. The matching relationship indicates one or more links between match keys associated with the first party system and the match keys associated with the third party system. The method includes assigning bridge identifiers for user identifiers associated with the first party system and the user identifiers associated with the third party system based on the matching relationship.

Abstract: Systems, methods, devices, and other techniques for preserving privacy when comparing private datasets from first and second computing systems. The second computing system identifies a first set of identifiers corresponding to records in a private database of the second computing system. The second computing system receives blinded versions of a set of identifiers corresponding to records in a private database of the first computing system. The second computing system determines an intersection or characteristic thereof of the records in the private database of the first computing system and the records in the private database of the second computing system based on matches between the blinded versions of the first and second sets of identifiers.

Abstract: A method for providing encrypted search includes receiving, at a user device associated with a user, a search query for a keyword that appears in one or more encrypted documents stored on an untrusted storage device and accessing a count table to obtain a count of documents that include the keyword. The method also includes generating a delegatable pseudorandom function (DPRF) based on the keyword, a private cryptographic key, and the count of documents. The method also includes evaluating a first portion of the DPRF and delegating a remaining second portion of the DPRF to the untrusted storage device which causes the untrusted storage device to evaluate the DPRF and access an encrypted search index associated with the documents. The untrusted storage device determines one or more encrypted documents associated with DPRF and returns, to the user device, an identifier for each encrypted document associated with the DPRF.

Abstract: A method for sharing read access to a document stored on memory hardware. The method includes receiving a shared read access command from a sharor sharing read access to a sharee for a document stored on memory hardware in communication with the data processing hardware, and receiving a shared read access request from the sharee. The shared read access command includes an encrypted value and a first cryptographic share value based on a write key, a read key, a document identifier, and a sharee identifier. The method also includes multiplying the first and second cryptographic share values to determine a cryptographic read access value. The cryptographic read access value authorizes read access to the sharee for the document. The method also includes storing a read access token for the sharee including the cryptographic read access value and the encrypted value in a user read set of the memory hardware.

Abstract: A method for performing encrypted search includes receiving a search query for a plurality of keywords from a user device that appear in one or more encrypted documents stored on an untrusted storage device. The method also includes accessing an encrypted search index to obtain a first list of document identifiers each representative of a document that includes a first keyword and a second keyword of the plurality of keywords. The method also includes, for each remaining keyword, determining a corresponding list of document identifiers each representative of a document that includes the first, second, and respective remaining keyword. The method includes determining, based on the first list of document identifiers and each corresponding list of document identifiers, a second list of document identifiers each representative of a document that includes each of the plurality of keywords. The method also includes returning the second list to the user device.

Abstract: A method for sharing read access to a document stored on memory hardware. The method includes receiving a shared read access command from a sharor sharing read access to a sharee for a document stored on memory hardware in communication with the data processing hardware, and receiving a shared read access request from the sharee. The shared read access command includes an encrypted value and a first cryptographic share value based on a write key, a read key, a document identifier, and a sharee identifier. The method also includes multiplying the first and second cryptographic share values to determine a cryptographic read access value. The cryptographic read access value authorizes read access to the sharee for the document. The method also includes storing a read access token for the sharee including the cryptographic read access value and the encrypted value in a user read set of the memory hardware.

Abstract: A method includes executing an instruction to execute a query for a data block, the data block associated with a corresponding memory level of a logarithmic number of memory levels (li) of memory, each memory level (li) including physical memory (RAMi) residing on memory hardware of a distributed system. The method also includes retrieving a value associated with the data block from an oblivious hash table using a corresponding key, and extracting un-queried key value pairs from the oblivious hash table associated with un-queried data blocks after executing a threshold number of queries for data blocks. The method also includes a multi-array shuffle routine on the extracted key value pairs from the oblivious hash table to generate an output array containing the un-queried key value pairs.

Abstract: A method for outsourcing exponentiation in a private group includes executing a query instruction to retrieve a query element stored on an untrusted server by selecting a prime factorization of two or more prime numbers of a modulus associated with the query element stored on the server, obtaining a group element configured to generate a respective one of the prime numbers, generating a series of base values using the prime factorization and the group element, and transmitting the series of base values from the client device to the server. The server is configured to determine an exponentiation of the group element with an exponent stored on the server using the series of base values. The method also includes receiving a result from the server based on the exponentiation of the group element with the exponent.

Abstract: Aggregated transaction data from a transaction data provider may be encrypted and exchanged with a content item selection system using commutative encryption algorithms. The transaction data provider and content item selection system may utilize a set of common identifiers that are each encrypted using a respective commutative encryption algorithm of the transaction data provider or content item selection system. The other of the transaction data provider or content item selection system encrypts the single-encrypted common identifier using a respective commutative encryption algorithm to generate double encrypted common identifiers. The double encrypted common identifiers may be used to match a set of common identifiers with transaction data. The transaction data may be encrypted and/or may include random offset values.

Abstract: A method (500) includes initializing a client state (250) on a client device (120) be executing a private batched sum retrieval instruction (200) to compute c sums O of data blocks (102) from an untrusted storage device (150). Each computed sum O stored on memory hardware (122) of the client device and including a sum of a corresponding subset S of exactly k data blocks. The method also includes a query instruction (300) to retrieve a query block Bq stored on the untrusted storage device by iterating through each of the c sums O of data blocks to identify one of the c sums O that does not include the query block Bq, instructing a service to pseudorandomly partition the untrusted storage device into partitions and sum the data blocks in each partition to determine a corresponding encrypted data block sum (302).