Advanced New Technologies Co., Ltd.

Alibaba Group Holding Limited

Alipay Labs (singapore) Pte. Ltd.

Wenbin Zhang

Baoli Ma

Zheng Liu

Lichun Li

Shan Yin

Huanyu Ma

Jiahui Cui

Chao Shen

Xuming Lu

Hui Fang

Danqing Hu

Shengjiao Cao

Weitao Yang

Hao Lei

Yuan Yuan

Ke Cheng Liu

Zhangjie Huang

Qian Sun

Ke Liu

Implementations of the present specification provide a blockchain-based transaction method and apparatus, and a remitter device. The method includes: calculating a transaction amount commitment, a first commitment random number ciphertext, a first transaction amount ciphertext, a second commitment random number ciphertext, and a second transaction amount ciphertext; and submitting transaction data to the blockchain, the transaction data including the transaction amount commitment, the first commitment random number ciphertext, the first transaction amount ciphertext, the second commitment random number ciphertext, and the second transaction amount ciphertext, for the transaction amount commitment, the first commitment random number ciphertext, and the first transaction amount ciphertext to be recorded into a remitter account, and the transaction amount commitment, the second commitment random number ciphertext, and the second transaction amount ciphertext to be recorded into a remittee account.

Blockchain-based transaction method and apparatus, and remitter device

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

Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for managing user authorizations for blockchain-based services. One of the methods includes: at a service platform, receiving, from a computing device associated with a user, an encryption key and data for storage on a blockchain, wherein the data includes public data and private data, and the encryption key encrypts the private data; storing the encryption key and an identifier (ID) of the data in a cache storage dedicated to storing smart contract data for executing a smart contract; and invoking an application programming interface (API) to enable a blockchain node to initiate a consensus algorithm to record the data and the ID of the data on a blockchain.

Managing user authorizations for blockchain-based custom clearance services

A computer-implemented information protection method comprises: obtaining a plurality of encrypted transaction amounts associated with transactions among a plurality of accounts, wherein each of the encrypted transaction amounts is associated with one of the accounts that sends or receives one of the transaction amounts, and the encryption of each of the transaction amounts at least conceals whether the one account sends or receives the one of the transaction amounts; generating a sum proof based on the obtained encrypted transaction amounts, the sum proof at least indicating that the transaction amounts are balanced; and transmitting the encrypted transaction amounts and the sum proof to one or more nodes on a blockchain network for the nodes to verify the transactions.

System and method for information protection

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.

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.

A computer-implemented method comprises: committing a transaction amount t of a transaction with a commitment scheme to obtain a transaction commitment value T, the commitment scheme comprising at least a transaction blinding factor r_t; encrypting a combination of the transaction blinding factor r_t and the transaction amount t with a public key PK_B of a recipient of the transaction; and transmitting the transaction commitment value T and the encrypted combination to a recipient node associated with the recipient for the recipient node to verify the transaction.

A computer-implemented method comprises: committing a transaction amount of a transaction with a commitment scheme to obtain a transaction commitment value, the commitment scheme comprising at least a transaction blinding factor; generating a first key of a symmetric key pair; encrypting a combination of the transaction blinding factor and the transaction amount t with the first key; and transmitting the transaction commitment value T and the encrypted combination to a recipient node associated with a recipient of the transaction for the recipient node to verify the transaction. The first key is a symmetrical key generated with Diffie-Hellman (DH) key exchange protocol that can be used to encrypt/decrypt the random numbers and the plaintext balances, thus providing convenient management. The method provides a robust privacy protection for transaction amounts, asset values, and blinding factors in commitment schemes.

A computer-implemented blockchain-based transaction obfuscation method includes: determining a submission time based on a base time and a submission time interval; determining that no actual transaction information is obtained between the base time and the submission time during the submission time interval; generating false transaction information; cryptographically encoding transaction content in the false transaction information; and subsequent to the submission time, submitting the false transaction information to a blockchain to obfuscate a number of actual transactions in the blockchain.

Blockchain-based transaction privacy

Implementations of this specification include receiving a synchronization request from a light-weight node of the blockchain network including an identity of the light-weight node; identifying one or more permissions associated with the identity of the light-weight node; determining an original world state structure associated with the block height and including a plurality of account records; identifying based on the one or more permissions, a subset of the plurality of account records that are authorized for access by the light-weight node; generating an isolated world state structure based on the original world state data structure including only the subset of the plurality of account records that are authorized for access by the light-weight node; sending a response to the light-weight node that includes the isolated world state data structure.

Data isolation in blockchain networks

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.

This disclosure relates to anonymous transactions based on ring signatures. In one aspect, a method includes receiving a remittance transaction. The remittance transaction is generated by a client device of a remitter by assembling unspent assets in an account corresponding to the remitter and masked assets in an account corresponding to a masked participant. Key images are obtained from a linkable spontaneous anonymous group (LSAG) signature of the remittance transaction. Values of the key-images are based on a private key, a public key, and unspent assets of the remitter. The LSAG signature is verified. The LSAG signature is generated by the client device of the remitter based on the private key and the public key of the remitter, and a second public key of the masked participant. The remittance transaction is executed when a transaction execution condition is met.

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Hangzhou, China

Wenbin Zhang