Abstract: 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.

Abstract: One or more embodiments of the present specification provide blockchain-based remittance methods and apparatuses. One method comprising: receiving, from an account of a remitter, a transaction for a remittance to an account of a remittee, wherein the transaction comprises a remittance amount of the remittance and at least one reserved amount corresponding to the remittance amount allocated by the remitter from a reserve fund list to the transaction; performing verification of the transaction, wherein the verification comprises determining whether a total amount of the at least one reserved amount comprised in the transaction is greater than or equal to the remittance amount; and in response to determining that the verification is successful: deducting the remittance amount from the balance of the account of the remitter, and adding the remittance amount to a balance of the account of the remittee.

Abstract: 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.

Abstract: Implementations are directed to cross-asset trading in blockchain networks, and include a first node providing transaction information based on a first value, a second value, and an exchange rate of a second node, receiving, from the second node, a first evidence set, a first range proof, and a digital signature of the second node, and submitting the transaction for verification based on the first range proof, a second range proof, the first evidence set, a second evidence set, a digital signature of the first node, and the digital signature of the second node, the transaction being executed to decrease a balance of the first node by the first value, increase a first balance of the second node by the first value, decrease a second balance of the second node by the second value, and increase a balance of the third node by the second value.

Abstract: The application provides a method, apparatus, and electronic device for implementing blockchain-based transactions.

Abstract: 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, and a second commitment random number ciphertext; and submitting transaction data to the blockchain, the transaction data including the transaction amount commitment, the first commitment random number ciphertext, and the second commitment random number ciphertext, for the transaction amount commitment and the first commitment random number ciphertext to be recorded into a remitter account, and the transaction amount commitment and the second commitment random number ciphertext to be recorded into a remittee account.

Abstract: 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 second public key PK_2_B of a recipient of the transaction, wherein: the recipient is further associated with a first public key PK_1_B as an address for receiving the transaction amount t; 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A computer-implemented method includes: determining assets held by a remitter, the assets to be spent in a remittance transaction between the remitter and one or more payees, in which each asset corresponds to a respective asset identifier, a respective asset amount, and a respective asset commitment value; determining a remitter pseudo public key and a remitter pseudo private key; determining a cover party pseudo public key, in which the cover party pseudo public key is obtained based on asset commitment values of assets held by the cover party; and generating a linkable ring signature for the remittance transaction.

Abstract: 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 second public key PK_2_B of a recipient of the transaction, wherein: the recipient is further associated with a first public key PK_1_B as an address for receiving the transaction amount t; 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.

Abstract: Implementations of the present specification include receiving, by a blockchain node in the blockchain network, a request to read a particular block of the blockchain, wherein the request is received from a light-weight node of the blockchain network and includes an identity of the light-weight node, and wherein the particular block includes an original Merkle tree associated with the particular block; identifying, by the blockchain node, permissions associated with the identity of the light-weight node; generating, by the blockchain node, an isolated Merkle tree based on the original Merkle tree included in the block, the isolated Merkle tree including only transactions from the original Merkle tree that are determined to be accessible by the light-weight node based on the identified permissions, wherein the isolated Merkle tree is consistent with the original Merkle tree; and sending, by the blockchain node, a response to the light-weight node including the isolated Merkle tree.

Abstract: Implementations of the specification include receiving transaction data associated with the transaction, the transaction data comprising: data representative of a plurality of assets, a first commitment hiding a first random number and a transaction amount of the transaction, a second commitment that hides a second random number and a change, the transaction amount and a third random number both encrypted by a public key of the second node, the change and a fourth random number both encrypted by a public key of the first node, and a zero-knowledge proof (ZKP); determining, based on the ZKP, whether the transaction is valid based on determining if the first random number is equal to the third random number, the second random number is equal to the fourth random number, and the transaction amount hidden in the first commitment is equal to the transaction amount encrypted by the public key of the second node.

Abstract: 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, and a second commitment random number ciphertext; and submitting transaction data to the blockchain, the transaction data including the transaction amount commitment, the first commitment random number ciphertext, and the second commitment random number ciphertext, for the transaction amount commitment and the first commitment random number ciphertext to be recorded into a remitter account, and the transaction amount commitment and the second commitment random number ciphertext to be recorded into a remittee account.

Abstract: 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.

Abstract: A computer-implemented method includes: determining assets held by a remitter, the assets to be spent in a remittance transaction between the remitter and one or more payees, in which each asset corresponds to a respective asset identifier, a respective asset amount, and a respective asset commitment value; determining a remitter pseudo public key and a remitter pseudo private key; determining a cover party pseudo public key, in which the cover party pseudo public key is obtained based on asset commitment values of assets held by the cover party; and generating a linkable ring signature for the remittance transaction.

Abstract: 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.

Abstract: 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.

Abstract: The application provides a method, apparatus, and electronic device for implementing blockchain-based transactions.