An item rating and recommendation platform identifies rating data including respective ratings of multiple items with respect to multiple users; identifies user-feature data including user features contributing to the respective ratings of the multiple items with respect to the multiple users; and receives, from a social network platform via a secret sharing scheme without a trusted initializer, manipulated social network data computed based on social network data and a first number of random variables. The social network data indicate social relationships between any two of the number of users. In the secret sharing scheme without the trust initializer, the social network platform shares with the item rating and recommendation platform manipulated social network data without disclosing the social network data. The item rating and recommendation platform updates the user-feature data based on the rating data and the manipulated social network data.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for training a multi-party secure logistic regression model (SLRM). One of the methods includes receiving, at a plurality of secure computation nodes (SCNs), a plurality of random numbers from a random number provider; encrypting, at each SCN, data stored at the SCN using the received random numbers; iteratively updating a secure logistic regression model (SLRM) by using the encrypted data from each SCN; and after iteratively updating the SLRM, outputting a result of the SLRM, wherein the result is configured to enable a service to be performed by each SCN.

The present invention discloses a method and system for securing digital transactions provided by a person operating a third-party computerized device designed to communicate with a multiparty signing system. The multiparty signing system may comprise a signing subsystem comprising a multiparty signing server designed to receive a request for digital signing and a first subset of end-user nodes designed to generate a group of key shares which can be utilized in MPC processes conducted by the multiparty signing server. The multiparty signing system may also comprise an approving subsystem designed for generating groups of key shares to approve the digital transactions. The approving subsystem may comprise a coordinator and a second subset of end-user nodes for generating groups of key shares. The multiparty signing server may be configured to receive from a third-party server a transaction to sign and to send a first request to the coordinator to receive a first group of key shares.

The subject matter discloses a system for enforcing correctness of a derivation key, comprising multiple computerized nodes, comprising a storage module configured to store a share of a key used as an input of a function generating the derivation key, a communication module configured to exchange information between the multiple computerized nodes, and a processing module configured to receiving a request to create the derivation key, performing an MPC process between the multiple computerized nodes, said MPC process is performed multiple times, in each time the MPC process comprises receiving the key shares as input, randomly selecting a function, outputting the outputs of the selected function to the multiple computerized nodes, the multiple computerized nodes lack access to the selected function, the multiple computerized nodes perform computations on the received outputs and exchange outputs of the computations to estimate correction of the key shares inputted into the MPC process.

The subject matter discloses a method for securing personal information, comprising securing the personal information stored on a data server using a cryptographic secret, said cryptographic secret is unique to a user, storing a first share of the cryptographic secret on a secret storage server communicating with the data server and a second share of the cryptographic secret on a computerized device controlled by the user, detecting a request from the data server to perform an action on the personal information, transmitting the request to the computerized device controlled by the user to use the second share of the cryptographic secret to decrypt the personal information, decrypting the personal information using the first share and the second share, without storing both the first share and the second share in a single device concurrently and performing the action on the personal information on the data server

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for training a multi-party secure logistic regression model (SLRM) by using secrete sharing (secret sharing) techniques. One of the methods includes dividing sample training data for a secure logistic regression model (SLRM) into a plurality of shares using secret sharing (SS), wherein each share is distributed to a secure computation node (SCN); iteratively updating parameters associated with the SLRM using each share of the sample training data, wherein the iterative updating continues until the occurrence of a predetermined condition; and after iteratively updating the parameters associated with the SLRM, outputting a training result configured for use by each SCN.

Embodiments of a secure multi-party computation method are provided. The method can include: dynamically converting a multi-party computation program segment into a first garbled circuit by using a multi-party computation operator of a first main body, and executing garbled gates of the first garbled circuit in sequence through an execution engine of the first main body, to encrypt data of the first main body; transmitting to a second main body the encrypted data of the first main body and identifiers for garbled gates of the first garbled circuit; performing a second encryption on the encrypted data of the first main body by the second main body in sequence according to the received identifiers for the garbled gates of the first garbled circuit, and returning to the first main body a result of the second encryption on the encrypted data of the first main body.

The present invention relates to a method of secure generation by a client device A and a server device B of at least a RSA current signature and a RSA next signature with a private exponent component d of an RSA key, comprising: a handshake phase (P1) comprising: a. receiving (S1) a handshake request comprising a hash of the next client value (pvA_next), b. checking (S2) the value of the next client value (pvA_next) and: when the next client value (pvA_next) equals a first default value (DUMMY): generating (S3) a new value (x) and updating the next server value (pvB_next) with the generated new value, and sending (S4) to the client device (A) the generated new value (x), to be used by the client device as next client value (pvA_next), when the next client value (pvA_next) is not equal to said first default value (DUMMY): checking the value of the next server value (pvB_next) and when the next server value (pvB_next) is equal to a second default value (NULL) and the next client value (pvA_next) equals the current server value (pvB): sending to the client device (A) a fix request; and when the next server value (pvB_next) is equal to said second default value (NULL) and the next client value (pvA_next) is not equal to the current server value (pvB), suspending performing said method. a signing phase (P2) performed by the server device (B) after the handshake phase and generating the current signature; said signing phase comprising: a. generating (S5) a server part of the current RSA signature (HS2) from the server device private exponent component (dB) and from an updated server dynamic offset (hB) function of the current server dynamic offset (hB) and of a server shift value (cB), said server shift value (cB) being function of the current server value (pvB), such that the current RSA signature can be generated by combining said server part of the current RSA signature (HS2) and a client part of the current RSA signature (HS1) generated by the client device (A), b. setting (S8) the current server dynamic offset (hB) to the updated server dynamic offset (hB) value, the current server value (pvB) to the value of the next server value (pvB_next) and the next server value (pvB_next) to a second default value (NULL), performing the handshake phase and the signing phase with the next signature as current signature, for generating the next signature.

The present invention discloses a method and system for securing digital transactions provided by a person operating a third-party computerized device designed to communicate with a multiparty signing system. The multiparty signing system may comprise a signing subsystem comprising a multiparty signing server designed to receive a request for digital signing and a first subset of end-user nodes designed to generate a group of key shares which can be utilized in MPC processes conducted by the multiparty signing server. The multiparty signing system may also comprise an approving subsystem designed for generating groups of key shares to approve the digital transactions. The approving subsystem may comprise a coordinator and a second subset of end-user nodes for generating groups of key shares. The multiparty signing server may be configured to receive from a third-party server a transaction to sign and to send a first request to the coordinator to receive a first group of key shares.

Some embodiments are directed to location-tracking system (100) comprising a location database (120) configured to receive a plurality of location updates from a plurality of tracking devices (112, 113), the plurality of location updates indicating the location of one or more objects, the location updates being stored encrypted with a cryptographic database encryption-key (130), multiple location-analysis devices execute a multi-party computation protocol on the encrypted location updates using a stored key-share, thus jointly computing a location-analysis result secret-shared among the multiple location analysis devices.