The disclosed systems, and methods are directed to a method for Privacy Preserving Inference (PPI) comprising receiving a first set of matrix information from a client device, generating k.sub.c−1 matrices by operating a first CSPRNG associated with the server with k.sub.c−1 seeds, computing inferences from the set of k.sub.c matrices, generating a matrix S.sub.s, generating k.sub.s−1 random matrices, computing a matrix Y.sub.k.sub.s in accordance with the inference matrix Y, the matrix S.sub.s and the k.sub.s−1 random matrices, transmitting a second set of matrix information to the client device, the second set of matrix information includes k.sub.s−1 seeds corresponding to the k.sub.s−1 random matrices and the matrix Y.sub.k.sub.s, receiving a matrix U from the client device, and computing an inference value y from the matrix U.

A validation system includes a plurality of validator devices. Each of the plurality of validator devices is assigned with a group signature. The validation system receives a cross-blockchain transaction from a plurality of transaction participant devices. The cross-blockchain transaction is associated with a plurality of blockchains. The validation system further controls a first validator device of the plurality of validator devices to apply an extended smart contract on the received cross-blockchain transaction. Further, the validation system validates the application of the extended smart contract on the cross-blockchain transaction based on the group signature assigned to each of the plurality of validator devices, to generate a transaction validation result. Further, the validation system transmits the generated transaction validation result, associated with the validation of the cross-blockchain transaction, to the plurality of blockchains. The transaction validation result is signed with the assigned group signature.

A method includes providing a public encryption key and a seed to a party and receiving a first encrypted data set encrypted using the public encryption key and marked by the party with a first mark based on the seed. The method also includes aggregating the first encrypted data set into an aggregated data set at an aggregator and receiving an indication that a first operation associated with the party has been performed on the aggregated data set. In response to the receiving, updating the first encrypted data set of the aggregated data set by updating the first mark to a second mark according to the first operation, generating a verification encrypted data set according to at least the second mark and at least the corresponding first operation, verifying the aggregated data set by comparing the updated first encrypted data set and the verification encrypted data set.

An approach for detecting potential medical conditions may be provided. Privacy laws and healthcare regulations may prevent healthcare entities from sharing data or acknowledging even seeing a patient. Secure multi-party computation can allow for the analysis of or more patient's private health data in a secure database. The private health data will only be visible to the health entity which owns or controls the data. Further, a system with oblivious random access memory may be presented which allows for the analysis of one or more patient's multiple private healthcare records. A medical condition diagnosis may be made from the analysis of the multiple private healthcare records by the secure multi-party computation using oblivious random access memory, without divulging information any private healthcare data to unauthorized parties.

There is provided a computer-implemented method of applying a first function to each data element in a first data set, the method comprising (i) determining whether each data element in the first data set satisfies a criterion, wherein the criterion is satisfied only if the result of applying the first function to the data element is equal to the result of applying a second first data set satisfies a criterion function to the data element; (ii) forming a compressed data set comprising the data elements in the first data set that do not satisfy the criterion; (iii) applying the first function to 10 each data element in the compressed data set; and (iv) forming an output based on the results of step (iii); wherein steps (i)-(iv) are performed using multiparty computation, MPC, techniques. A corresponding system and worker node are also provided.

Some embodiments are directed to an authentication system (100; 101; 102) for computing an authentication token for a service provider to authenticate a user system to the service provider, the authentication system comprising a processor configured to jointly blind with a user system an encrypted user identity and to compute an encrypted identity for the service provider from the blinded encrypted user identity.

A method, apparatus and computer program product to detect whether specific sensitive data of a client is present in a cloud computing infrastructure is implemented without requiring that data be shared with the cloud provider, or that the cloud provider provide the client access to all data in the cloud. Instead of requiring the client to share its database of sensitive information, preferably the client executes a tool that uses a cryptographic protocol, namely, Private Set Intersection (PSI), to enable the client to detect whether their sensitive information is present on the cloud. Any such information identified by the tool is then used to label a document or utterance, send an alert, and/or redact or tokenize the sensitive data.

A blockchain-based data processing method and apparatus are provided. The method comprises: by a node device of a service acceptance platform, receiving service processing application data of a target user; generating a first service processing result; encrypting the first service processing result using a public key of a node device of a service processing entity; and sending, a first transaction to a blockchain for the first transaction to be recorded in a distributed database of the blockchain upon verification of the first transaction by a plurality of node devices associated with the blockchain according to a consensus mechanism, wherein: the first transaction comprises the encrypted first service processing result, and the plurality of node devices associated with the blockchain comprises the node device of the service acceptance platform and the node device of the service processing entity.

In one set of embodiments, each server executing a secure multi-party computation (MPC) protocol can receive shares of inputs to the MPC protocol from a plurality of clients, where each input is private to each client and where each share is generated from its corresponding input using a threshold secret sharing scheme. Each server can then verify whether the shares of the plurality of inputs are valid/invalid and, for each invalid share, determine whether a client that submitted the invalid share or a server that holds the invalid share is corrupted. If the client that submitted the invalid share is corrupted, each server can ignore the input of that corrupted client during a computation phase of the MPC protocol. Alternatively, if the server that holds the invalid share is corrupted, each server can prevent that corrupted server from participating in the computation phase.

A method may include receiving, from a first trusted authority (which may be distributed), a secret key specific to a party for use in posting to a blockchain. The method may also include receiving, from a second trusted authority (which may be distributed), a correlated randomness component specific to the party and associated with a given temporal segment; and computing, using an input from the party and the correlated randomness component in a non-interactive multi-party computation (NIMPC), an NIMPC-encrypted input associated with the party for the given temporal segment. The method may also include encrypting the NIMPC-encrypted input according to a blockchain encryption algorithm to yield a ciphertext, and submitting the ciphertext to a block associated with the given temporal segment in a blockchain, the block able to be decrypted after a future block of the blockchain is posted after the block is posted to the blockchain.