Abstract: Example blockchain-based user element authentication methods, apparatuses, systems and computer-readable media are provided. In an example, a node device in a blockchain receives a smart contract invocation transaction, where the smart contract invocation transaction includes an encrypted to-be-authenticated user element provided by a user client. In response to the smart contract invocation transaction, the node device invokes encryption conversion logic in the smart contract, decrypts the encrypted to-be-authenticated user element in a trusted computing environment, and performs secondary encryption processing. The user element authentication authority decrypts the to-be-authenticated user element and performs user element authentication. The node device obtains an authentication result submitted by the user element authentication authority and stores the authentication result in the blockchain.

Abstract: One or more embodiments of the present specification provide privacy protection-based multicollinearity detection methods, apparatuses, and systems. Data alignment is performed by a member device on respective local feature data with other member devices to construct a joint feature matrix. Privacy protection-based multi-party matrix multiplication computation is performed to compute a product matrix of a transposed matrix of the joint feature matrix and the joint feature matrix. An inverse matrix of the product matrix is determined based on respective submatrices of the product matrix. A variance inflation factor of each attribute feature is determined by the member device with the other member devices using respective submatrices of the inverse matrix and the respective local feature data. Multicollinearity is determined by the member device with the other member devices based on fragment data of the variance inflation factor of each attribute feature.

Abstract: Blockchain-based transaction methods, apparatuses and systems are provided. A transaction party invokes a smart contract in a blockchain system to register a digital identity on a blockchain for a digital object in the blockchain system and to write an owner identity of the digital object into a digital identity document of the digital object. If one or more transaction counterparties want to obtain ownership of the digital object, they can invoke the smart contract in the blockchain system to initiate a request of a transaction, further invoke the smart contract in the blockchain system to complete a transaction, determine a new owner of the digital object, and update the owner identity of the digital object on the blockchain.