Advanced New Technologies Co., Ltd.

Alibaba Group Holding Limited

Shan Yin

Lichun Li

Zheng Liu

Wenbin Zhang

Baoli Ma

Huazhong Wang

Wenzhen Lin

Yashun Zhou

Pengfei Ying

Yuan Zhao

Privacy protection methods, systems, and apparatus, including computer programs encoded on computer storage media, are provided. One of the methods is performed by a second computing device and includes: receiving a data request for object data from a first computing device, wherein the object data is associated with an object and is stored in the second computing device; performing encryption of the object data using a public key associated with the object based on the data request to generate a first ciphertext; obtaining verification data based on the first ciphertext for verifying whether a ciphertext to be verified corresponds to the object data; and sending the verification data to the first computing device for the first computing device to execute a cryptography protocol with a third computing device based on the verification data.

Method and apparatus for obtaining input of secure multiparty computation protocol

A method for implementing blockchain-based transactions comprises: determining a transaction amount to be remitted from a remitter's blockchain account into a receiver's blockchain account, wherein a balance of the remitter's blockchain account comprises multiple reserve balances, and commitments of the reserve balances are recorded in a blockchain; selecting one or more of the reserve balances from the remitter's blockchain account, wherein the sum of the selected one or more reserve balances is not smaller than the transaction amount; and submitting to the blockchain a transaction comprising an identification of each of the selected one or more reserve balances and a commitment of the transaction amount, for the selected one or more reserve balances to be removed from the remitter's blockchain account and the transaction amount to be added to the receiver's blockchain account.

Method, apparatus and electronic device for blockchain transactions

Implementations of the present disclosure include obtaining a secret key, by a client node, according to a threshold secret sharing scheme agreed to by a number of client nodes; generating one or more commitment values of a confidential transaction of the client node by applying a cryptographic commitment scheme to transaction data; generating encrypted transaction information of the confidential transaction by encrypting the transaction data using the secret key; and transmitting, to a consensus node of a blockchain network, a content of the confidential transaction for execution, wherein the content of the confidential transaction includes: the one or more commitment values; the encrypted transaction information; and one or more zero-knowledge proofs of the transaction data.

Recovering encrypted transaction information in blockchain confidential transactions

A method for implementing blockchain-based transactions comprises: determining a transaction amount to be remitted from a blockchain account of a remitter into a blockchain account of a receiver, wherein the blockchain account of the remitter records a homomorphic encryption ciphertext of the remitter's balance, the blockchain account of the receiver records a homomorphic encryption ciphertext of the receiver's balance; generating a homomorphic encryption ciphertext of the transaction amount with respect to the remitter and a homomorphic encryption ciphertext of the transaction amount with respect to the receiver; and submitting to the blockchain a transaction for the homomorphic encryption ciphertext of the transaction amount with respect to the remitter to be subtracted from the homomorphic encryption ciphertext of the remitter's balance and for the homomorphic encryption ciphertext of the transaction amount with respect to the receiver to be added to the homomorphic encryption ciphertext of the receiver's balance.

Privacy protection methods, systems, and apparatus, including computer programs encoded on computer storage media, are provided. One of the methods is performed by a first computing device and includes: obtaining a plurality of object IDs, wherein the plurality of object IDs include a target object ID; sending the plurality of object IDs to a second computing device storing a plurality of pieces of data respectively associated with the plurality of object IDs for the second computing device to generate a plurality of ciphertexts respectively based on the plurality of pieces of data; and executing a cryptography protocol with the second computing device to obtain a ciphertext corresponding to the target object ID from the plurality of ciphertexts generated by the second computing device, wherein the target object ID is unknown to the second computing device.

Embodiments of the application provide a method, apparatus, and electronic device for implementing blockchain-based transactions. The method comprises: determining a transaction amount to be remitted from a remitter's blockchain account into a receiver's blockchain account, wherein a commitment of the remitter's balance is recorded with the remitter's blockchain account in a blockchain, a commitment of the receiver's balance is recorded with the receiver's blockchain account in the blockchain; obtaining a commitment of the transaction amount by using the homomorphic encryption algorithm according to the transaction amount; and submitting to the blockchain a transaction comprising information of the remitter's and the receiver's blockchain accounts, and the commitment of the transaction amount, for the commitment of the transaction amount to be deducted from the commitment of the remitter's balance and the commitment of the transaction amount to be added to the commitment of the receiver's balance.

A method comprises: selecting one or more blockchain assets from a remitter's blockchain account according to a transaction amount of a transaction to be remitted from the remitter's blockchain account into a receiver's blockchain account, wherein a total asset amount represented by the selected one or more blockchain assets is not less than the transaction amount, and a commitment of an individual asset amount represented by each of the selected one or more blockchain assets is recorded in a blockchain; generating a commitment of the transaction amount; and submitting to the blockchain the transaction comprising information of the selected one or more blockchain assets and the commitment of the transaction amount, for the selected one or more blockchain assets to be removed from the remitter's blockchain account and one or more blockchain assets corresponding to the commitment of the transaction amount to be added to the receiver's blockchain account.

Embodiments of a secure multi-party computation method applicable to any computing node deployed in a distributed network are provided. A plurality of computing nodes is deployed in the distributed network. The plurality of computing nodes jointly participates in a secure multi-party computation based on private data respectively held by the computing nodes. The method includes: generating a computing parameter related to private data held by one computing node based on a secure multi-party computation algorithm; transmitting the computing parameter to other computing nodes participating in the secure multi-party computation for the other computing nodes to perform the secure multi-party computation based on collected computing parameters transmitted by the computing nodes participating in the secure multi-party computation; and creating an audit log corresponding to the computing parameter, the audit log recording description information related to the computing parameter.

Multi-party security computing method and apparatus, and electronic device

Embodiments of a multi-party secure computation method applicable to any one computing node deployed in a distributed network are provided. A plurality of computing nodes are deployed in the distributed network, the plurality of computing nodes jointly participate in a secure multi-party computation based on respectively held private data, and the computing node that performs the method is connected to a trusted random source. The method includes: obtaining a trusted random number from the trusted random source; performing an operation on the held private data based on the obtained trusted random number to obtain an operation result; and transmitting a computing parameter comprising at least the trusted random number to other computing nodes participating in secure multi-party computation, so that the other computing nodes perform the secure multi-party computation based on collected computing parameters transmitted by the computing nodes participating in the secure multi-party computation.

Secure multi-party computation method and apparatus, and electronic device

A method for implementing blockchain-based transactions includes: determining a to-be-remitted amount for each of a plurality of remitters participating in a transaction and a to-be-received amount for each of a plurality of receivers participating in the transaction, wherein the plurality of remitters include one or more real remitters, the plurality of receivers include one or more real receivers, and the plurality of remitters include one or more cover-up remitters and/or the plurality of receivers include one or more cover-up receivers; generating a commitment of the to-be-remitted amount corresponding to the each remitter and a commitment of the to-be-received amount corresponding to the each receiver; and submitting the transaction to a blockchain for execution, wherein the transaction comprises blockchain account addresses of the remitters and receivers, and the commitments of the to-be-remitted amounts and the to-be-received amounts.

Implementations of the present disclosure include receiving a content of a confidential transaction of a client node, by a consensus node of a blockchain network, wherein the content of the confidential transaction includes one or more commitment values of the confidential transaction generated by the client node by applying a cryptographic commitment scheme to transaction data of the confidential transaction, and encrypted transaction information generated by encrypting the transaction data using a secret key of the client node, wherein a secret key is obtained by the client node according to a threshold secret sharing scheme with a plurality of client nodes, and one or more zero-knowledge proofs of the transaction data; verifying that the confidential transaction is valid based on the content of the confidential transaction; and storing the encrypted transaction information on a blockchain of the blockchain network.

A node device in a blockchain receives an asset issuance transaction from an asset issuer, where the asset issuance transaction comprises a commitment value and a proof for performing a zero-knowledge proof with respect to the commitment value, and where the commitment value is calculated by inputting at least an asset type of a target asset object issued by the asset issuer to a commitment function. The zero-knowledge proof with respect to the commitment value based on the proof is initiated. It is determined that the asset type of the target asset object is in a set of legal asset types allowed to be issued by the asset issuer. In response to determining that the asset type of the target asset object is in the set of legal asset types allowed to be issued by the asset issuer, the commitment value to the blockchain is issued for storage.

Method, apparatus and electronic device for blockchain-based asset issuance

Embodiments of a secure multi-party computation method applicable to any one computing node of a plurality of computing nodes deployed in a distributed network are provided. The plurality of computing nodes jointly participate in a secure multi-party computation based on private data held by each computing node. The computing node is connected to a trusted key source, and the method includes: obtaining a trusted key from the trusted key source; encrypting the private data held by the computing node based on the obtained trusted key to obtain ciphertext data; transmitting a computing parameter comprising at least the ciphertext data to other computing nodes participating in the secure multi-party computation, so that the other computing nodes perform the secure multi-party computation based on collected computing parameters transmitted by the computing nodes participating in the secure multi-party computation.

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Hangzhou, China

Shan Yin