Methods and apparatus provide digital media with spatial audio to a blockchain. The blockchain network executes a decentralized application (Dapp) with a user interface (UI) that enables a user to select audio for spatialization and uploading to the blockchain. The spatial audio transmits to the blockchain network to reduce processing and transmission of network data.

Advertisement targeting with a secure identity is described. A request pertaining to supplemental content targeted to an attribute of a user is posted from a requesting system to a blockchain. It is then determined that a user profile includes an attribute that matches with the attribute of the request via the blockchain. The supplemental content is then caused to be displayed in response to the determination that the user profile includes the attribute that matches with the attribute of the request and via a user interface of a device associated with a user associated with the user profile.

This document relates to 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 receiving, by a first computing system of a secure MPC system and from a client device, a digital component request and a nonce. The first computing system generates, based on the nonce and a function, an array including a share of a Bloom filter representing user group identifiers for user groups that include a user of the client device as a member. For each of multiple user group identifiers, the first computing system calculates, in collaboration with one or more second computing systems of the secure MPC system and using the array, a respective first secret share of one or more user group membership condition parameters.

This document relates to 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 receiving, by a first server of a secure MPC system from a client device, a digital component request. The first server identifies, for each digital component in a set, a selection value and a priority tier. For each tier, the first server determines, using a secure MPC process in collaboration with one or more second servers of the secure MPC system, a first secret share of a winner parameter for each digital component in the priority tier. The first server identifies a highest tier for which a given digital component has a winner parameter that indicates that the given digital component is a winning digital component.

Collecting surveys with a secure identity is described. A request (i) pertaining to a survey and (ii) targeted to an attribute of a user is posted from a requesting system to a blockchain. It is determined, via the blockchain, that a user profile includes an attribute that matches with the attribute of the request. The request to a device associated with the user profile is transmitted via the blockchain and in response to determining that the user profile includes the attribute that matches with the attribute of the request. A response to the request is received from the device associated with the user profile. A commitment based on the response to the request is generated to the blockchain. The commitment is transmitted from the blockchain to the requesting system.

Systems and methods are described that use tag authentication and presence verification techniques in connection with a variety of transactions. In certain embodiments, an authentication device may verify the authenticity of a secure tag by determining whether the secure tag stores secret information provisioned by a trusted authority. In some embodiments, such an authentication process may be performed without exposing the secret information to the authentication device, thereby maintaining integrity of the secure tag. In other embodiments, insecure tags and/or tags that do not include secret information are used.

Collecting surveys with a secure identity is described. A request (i) pertaining to a survey and (ii) targeted to an attribute of a user is posted from a requesting system to a blockchain. It is determined, via the blockchain, that a user profile includes an attribute that matches with the attribute of the request. The request to a device associated with the user profile is transmitted via the blockchain and in response to determining that the user profile includes the attribute that matches with the attribute of the request. A response to the request is received from the device associated with the user profile. A commitment based on the response to the request is generated to the blockchain. The commitment is transmitted from the blockchain to the requesting system.

A system for authenticating user identities and exchange data via a blockchain is described. Initially, first data related to a commitment being made by a user is obtained by a client device. The first data is partly based on information identificatory or a characteristic of the user. The first data is sent by the client device to a verification system. The verification system then verifies that the first data corresponds with second data generated using identification documentation of the user. The data representing the commitment to a blockchain is posted by the verification system responsive to a successful verification.

A system for authenticating user identities and exchange data via a blockchain is described. Initially, first data related to a commitment being made by a user is obtained by a client device. The first data is partly based on information identificatory or a characteristic of the user. The first data is sent by the client device to a verification system. The verification system then verifies that the first data corresponds with second data generated using identification documentation of the user. The data representing the commitment to a blockchain is posted by the verification system responsive to a successful verification.

A blockchain based numerical value ranking method includes: using, by a first participant, a public key of the first participant to encrypt a private value of the first participant to obtain an encrypted text of the first participant; obtaining encrypted texts of other participants, and generating a challenge value having a preset bit length; based on the challenge value and the private value of the first participant, and the encrypted texts and public keys of the other participants, determining mixed results of the first participant with respect to the other participants; and determining a numerical value ranking result between the first participant and a second participant based on the mixed result of the second participant with respect to the first participant.