Multiple elements are efficiently read from a secured array. A secure text array <a>=(<a[0]>, . . . , <a[n1]>) where an array a=(a[0], . . . , a[n1]) having a size of n is secured, secure text <x> of an integer x that is equal to or higher than 0 and less than n, and in integers i.sub.0, . . . , i.sub.m-1 that are equal to or higher than 0 and less than n are input into an input part 11. A secure shift part 12 secure-shifts the secure text array <a> by <x> to obtain a secure text array <a>=(<a[0]>, . . . , <a[n1]>) where an array a=(a[0], . . . , a[n1]) obtained by shifting leftward the array a by x is secured. An array generation part 13 generates a secure text array <b>=(<a[i.sub.0]>, . . . , <a[i.sub.m-1]>) from the secure text array <a>.

A method of applying proof of lottery to select block forgers in a blockchain, comprising performing the following at a certain one of a plurality of computing nodes connected to a blockchain network: (1) transmitting one or more of a plurality of participation transactions submitted by at least some of the plurality of computing nodes for participating in selection process conducted to select forgers from the plurality of computing nodes to forge blocks to be added to the blockchain; (2) determining a respective forger, during each selection process, by applying a selection function to an outcome of a hash function and a plurality of participation transactions extracted from a first subset of blocks preceding the respective block, the hash function is applied to a second subset of blocks preceding the respective block; and (3) forging the respective block in case the certain computing node is selected as the respective forger.

A method includes receiving, on a computer-implemented system and from user, an identification of data and an identification of an algorithm and, based on a user interaction with the computer-implemented system comprising a one-click interaction or a two-click interaction. Without further user input, the method includes dividing the data into a data first subset and a data second subset, dividing the algorithm (or a Boolean logic gate representation of the algorithm) into an algorithm first subset and an algorithm second subset, running, on the computer-implemented system at a first location, the data first subset with the algorithm first subset to yield a first partial result, running, on the computer-implemented system at a second location separate from the first location, the data second subset with the algorithm second subset to yield a second partial result and outputting a combined result based on the first partial result and the second partial result.

Systems, methods, and computer-readable media for achieving privacy for both data and an algorithm that operates on the data. A system can involve receiving an algorithm from an algorithm provider and receiving data from a data provider, dividing the algorithm into a first algorithm subset and a second algorithm subset and dividing the data into a first data subset and a second data subset, sending the first algorithm subset and the first data subset to the algorithm provider and sending the second algorithm subset and the second data subset to the data provider, receiving a first partial result from the algorithm provider based on the first algorithm subset and first data subset and receiving a second partial result from the data provider based on the second algorithm subset and the second data subset, and determining a combined result based on the first partial result and the second partial result.

A method is presented for secure determination of a solution (S) to a computational task by a pooled resource or group having a plurality of participants (P), the group operating in a trust-less, or dealer-free, system or manner. Access to a resource or reward is offered in exchange for the solution. Individuals generate their own key pair and use their public key to establish with the group an initial shared public key that they can all use to find a solution to the task. The resource or reward can be secured by the verified shared public key. Because the private keys of each participant were used in the determination of the initial shared public key that lead to the solution then participants must then collaborate to unlock the resource or reward because the corresponding shared private key can only be generated by all participants or a pre-agreed threshold of participants.

Systems and methods for generating min-increment counting bloom filters to determine count and frequency of device identifiers and attributes in a networking environment are disclosed. The system can maintain a set of data records including device identifiers and attributes associated with device in a network. The system can generate a vector comprising coordinates corresponding to counter registers. The system can identify hash functions to update a counting bloom filter. The system can hash the data records to extract index values pointing to a set of counter registers. The system can increment the positions in the min-increment counting bloom filter corresponding to the minimum values of the counter registers. The system can obtain an aggregated public key comprising a public key. The system can encrypt the counter registers using the aggregated shared key to generate an encrypted vector. The system can transmit the encrypted vector to a networked worker computing device.

In one embodiment, a method includes scanning, by a first device, a code from a second device and determining, by the first device, information comprising a peer identifier and a first certificate hash using the code. The method also includes initiating, by the first device, a connection with the second device using the peer identifier and receiving, by the first device, a second certificate hash from the second device via the connection. The method further includes validating, by the first device, the second certificate hash using the first certificate hash, establishing a session with the second device, and transferring, by the first device, account information to the second device via the session.

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.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for selecting and distributing digital components to client devices in ways that protect user privacy and confidential data of content platforms and/or digital component providers are described. In one aspect, a method includes receiving, by a secure distribution system and from a client device of a user, a digital component request that includes, for each of multiple content platforms that distribute digital components to users, a corresponding user embedding comprising weights indicative of the relevance of multiple features to the user. The secure distribution system provides each user embedding as input to a respective isolated execution environment for the content platform corresponding to the user embedding, wherein the secure distribution system hosts each isolated execution environment. Digital component selection data generated based on the user embedding is received from each isolated execution environment.

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.