This document describes systems and techniques for using secure MPC to select digital components in ways that preserve user privacy and protects the security of data of each party that is involved in the selection process. In one aspect, a method includes obtaining, by a first computer of a secure multi-party computation (MPC) system, at least a first share of a set of contextual properties of an environment in which a selected digital component will be displayed at a client device. For each digital component in a set of digital components, at least a first share of an eligibility expression that defines a relationship between a set of eligibility criteria for the digital component is obtained. A determination is made, based on the at least first share of the set of contextual properties and the at least first share of the eligibility expression, a first share of an eligibility parameter.

A method of communicating a secret (k.sub.0, k.sub.1) on the Bitcoin blockchain is disclosed. The method comprises sending information identifying secrets selectable by the recipient and receiving a first public key (U.sub.i) of an elliptic curve cryptography system, corresponding to a first secret (S.sub.i) selected for access by the recipient and for which a first private key (m) is accessible to the recipient. A second public key (U.sub.1-i) is received, corresponding to a second secret not selected for access by the recipient, wherein a corresponding second private key is not available to the recipient. First and second secrets encrypted by means of the respective first and second public keys (X.sub.0, X.sub.1) are sent to the recipient, wherein the first secret is accessible to the recipient by means of the first private key, the second secret is inaccessible to the recipient, and the sender is unable to distinguish between the first and second secrets.

A system for authenticating a user accessing a device includes an authentication server and a ticket granting server. The authentication server is configured to generate a part of an authentication ticket which is combinable with at least one other part generated by at least one other authentication server to produce a complete authentication ticket, and to generate a part of a user session key which is combinable with at least one other part generated by the at least one other authentication server to produce a combined user session key. The ticket granting server is configured to authenticate the user by collaboratively, with at least one other ticket granting server, decrypting user request information using the combined user session key and comparing content of the decrypted user request information with the complete authentication ticket.

Standardized digital signature schemes (e.g., Rivest-Shamir-Adleman (RSA), Digital Signature Algorithm (DSA), Elliptical Curve Digital Signature Algorithm (EC-DSA), etc.) may be employed to prove authenticity of a message containing credentials. Proving possession of valid credentials may be performed using a combination of garbled circuits with message authentication codes (MACs) and proof of knowledge protocols (e.g., Sigma protocol, Schnorr protocol, etc.). Such techniques may allow proving entities to prove possession of valid credentials using standardized signature schemes without revealing those credentials directly to a verifying entity.

Embodiments can perform efficient OT (oblivious transfer) protocols to efficiently establish OT correlations that could be used for an MPC protocol. The present embodiments relate to a non-interactive OT (NIOT) protocol using a key encapsulation mechanism (KEM). Two OT protocols are non-interactive OTs, in which a sender generates private, public key pair (pk, sk) that is independent of its input or generated OT correlations. The two OT protocols use a cryptographic hash function and a one-way secure dense key encapsulation mechanism (KEM).

Some embodiments are directed to a computation device configured to verify that an edit script is for transforming a first string to a second string. The edit script has match operations and difference operations as allowed edit operations. The computation device obtains a representation of the edit script and subsequently performs a validation computation. For each match operation, the computation device determines a character at a current position in the first string and a character at a current position in the second string, verifies that they match, increments the current position in the first string by one and increments the current position in the second string by one. For each difference operation, the computation device increments the current position in the first string and/or the current position in the second string by one.

A method for encoding can include generating a data structure defining a Boolean circuit including a memory storing original data, inputs and outputs, logic gates, and wires interconnecting the inputs, the logic gates and the outputs, the memory including, for each bit of the original data, a memory cell including a logic gate performing a logic operation depending on a value of the bit, the Boolean circuit configured to receive input data for selecting and reading a memory cell, and to provide a binary data of a bit read in the selected memory cell and address data of the bit in the original data. Generating the data structure including: generating a valid data for each binary state of each wires of the Boolean circuit, and computing truth table values of the logic gates as a function of the valid input and output data, and a logical operation of the logic gate.

Embodiments are directed towards classifying data. A machine learning (ML) engine may select an ML model that may employ a cryptographic multi-party computation (MPC) protocol based on model preferences, including a parameter model, provided by a client. A randomness engine may be employed to provide random values and other random values based on the MPC protocol such that the random values may be provided to the client and the other random values may be provided to an answer engine. Input values that correspond to fields in the parameter model may be provided by the client such that the input values may be based on the MPC protocol and the random values. The answer engine may be employed to provide partial results to the question based on the ML model, the input values, and the MPC protocol that may be provided to the client.

The present invention relates to a communication arrangement configured to allow wired communication between an electronic host device and an electrical slave device, such as between a smart phone and a smart card during an enrollment process. The invention also relates to a method for providing instructions to a user of a smart card during an enrollment process.

The subject matter discloses a computerized system, comprising a computerized device communicating with a third party server, that comprises a memory unit that stores a representation of a Boolean circuit and a processing unit for calculating a result of the Boolean circuit according to a string used as input for the Boolean circuit and calculating a first predefined function on the result of the Boolean circuit. The system also comprises a first auxiliary server communicating with the computerized device, the first auxiliary server comprises a processing unit for calculating a second predefined function on the result of the Boolean circuit received from the computerized device and a second auxiliary server communicating with the computerized device comprises a processing unit for comparing the result of the first predefined function and the result of the second predefined function.