A secure maximum value computation apparatus, assuming that a set X={[[x.sub.1]], [[x.sub.2]], . . . , [[x.sub.n]]}, includes an output unit 1 that outputs [[x.sub.1]] and [[1]] as a maximum secret value [[y]] and a flag [[z(x.sub.1)]], respectively, when n=1 holds, a comparison unit 2 that computes a comparison result of which is larger with respect to a predetermined order for each pair {[[x.sub.i]], [[x.sub.j]]}⊂X of elements of the X, a flag computation unit 3 that computes whether all comparison results related to each of the [[x.sub.i]]s are “large” for each of the [[x.sub.i]]s to set a computed value as a flag [[z(x.sub.i)]], and a maximum value computation unit 4 that uses the [[z(x.sub.i)]] to computes a maximum value [[y]].

This describes a privacy preserving machine learning platform. In one aspect, a method includes receiving, by a first computing system of multiple multi-party computation (MPC) systems, an inference request including a first share of a given user profile. A predicted label for the given user profile is determined based at least in part on a first machine learning model. A predicted residue value for the given user profile indicating a predicted error in the predicted label is determined. The first computing system determines the first share of the predicted residue value for the given user profile based at least in part on the first share of the given user profile and a second machine learning model. The first computing system receives, from a second computing system of the MPC computing systems, data indicating the second share of the predicted residue value for the given user profile.

Systems and methods of managing a shared cryptographic account for a first user and at least one second user in a blockchain based computer network, including: generating, by a first computing device of the first user, a first share of a cryptographic key, generating, by a server, a corresponding second share of the cryptographic key, wherein the cryptographic key corresponds to a public key and private key pair, and wherein the private key is configured to decrypt shares of the cryptographic key that are encrypted by the public key, generating a group ID for a group of users of the shared cryptographic account, distributing, by the server, the first share among each of the at least one second user, and enforcing a signing logic scheme for users of the group when signing with the shared cryptographic account.

A computer-implement method comprises: selecting a trusted computing node via smart contract on a blockchain; completing remote attestation of the selected trusted computing node; writing secret information to an enclave of the selected node; causing a thin device to establish a private connection with the selected node without revealing the secret information; and causing the selected node to act as a proxy on the blockchain for the device. Another method comprises: receiving a signed device access request from a device owner; validating, by a verification node, the received request; executing, by a verification node, a smart contract on a blockchain based on the received request; and producing, based on the executed smart contract, an output command to access the device for the device to validate, decrypt and execute.

Systems and methods for preserving privacy in dark pool trading environments are provided. The methods include receiving buy orders that include encrypted buy order information; receiving sell orders that include encrypted sell order information; determining whether at least one received buy order matches with at least one received sell order; and when there is a match, executing a transaction based on the match. The determination is made without revealing the encrypted information to an operator of the dark pool, thereby preserving the confidentiality of the information until the transaction is executed.

A secure multi-party computation method and apparatus, a device, and a storage medium are provided, which belong to the field of data security technologies. The method includes: performing homomorphic encryption processing on first plaintext data to generate first ciphertext data; transmitting encrypted data containing the first ciphertext data to a second node device; receiving difference ciphertext data transmitted by the second node device; and decrypting the difference ciphertext data to obtain a positive and negative property of a difference between the first plaintext data and the second plaintext data. The foregoing method and apparatus, device, and storage medium are conducive to reducing the number of times of communications of secure multi-party computation, have low communication overhead and high computation efficiency, and enable magnitude comparison and equality testing to be performed simultaneously.

A method includes obtaining, from a server, a filter including a set of encrypted identifiers each encrypted with a server key controlled by the server. The method includes obtaining a request that requests determination of whether a query identifier is a member of a set of identifiers corresponding to the set of encrypted identifiers. The method also includes transmitting an encryption request to the server that requests the server to encrypt the query identifier. The method includes receiving, from the server, an encrypted query identifier including the query identifier encrypted by the server key and determining, using the filter, whether the encrypted query identifier is not a member of the set of encrypted identifiers. When the encrypted query identifier is not a member of the set of encrypted identifiers, the method includes reporting that the query identifier is not a member of the set of identifiers.

Multiple systems, methods, and computer program product embodiments for password-less authentication using key agreement and multi-party computation (MPC). In one or more embodiments, following an authentication request received by a host computing device, the host computing device and a user computing device generate a shared key using a key agreement algorithm. Then, the host computing device generates a challenge that is encrypted using the shared key and transmitted to the user computing device. The user computing device decrypts the challenge after regenerating the shared key and sends the decrypted result to the host computing device as the challenge response. The authentication request is granted by the host computing device if the challenge and the challenge response match. New keys and a new challenge are generated for each authentication request. This process relies on public key cryptography eliminating the needs for passwords.

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.

An arithmetic apparatus includes an interface and a circuity. The interface is connected to an information processing apparatus that is connected to a client apparatus and that processes data in an encrypted state. The circuitry acquires, from the information processing apparatus, encryption input data or encryption target data encrypted with a first encryption key. The circuitry decrypts the acquired, encryption input data or encryption target data with a first decryption key. Then, the circuitry executes a predetermined arithmetic operation on the decrypted arithmetic operation target data, encrypts data of an arithmetic operation result obtained by the predetermined arithmetic operation with the first encryption to key, and outputs the encrypted data of the arithmetic operation result to the information processing apparatus.