Abstract: 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.

Abstract: A node device of a blockchain receives an asset transfer transaction sent by an asset transferor, where the asset transfer transaction comprises a commitment value that is calculated by inputting at least an asset type of an output asset object in the asset transfer transaction to a commitment function, and a proof used to perform a zero-knowledge proof on the commitment value. The zero-knowledge proof on the commitment value is performed, to determine that an asset type of an input asset object corresponds to the asset type of the output asset object in the asset transfer transaction. In response to determining that the asset type of the input asset object corresponds to the asset type of the output asset object in the asset transfer transaction, the commitment value corresponding to the output asset object is sent to the blockchain for deposit.

Abstract: 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.

Abstract: Implementations of the specification include receiving transaction data associated with a transaction, the transaction data comprising: data representative of a plurality of assets, a first commitment that hides a first random number and a transaction amount, 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 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: 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: Implementations of the present disclosure include receiving, by a consensus node from a first account, a digitally signed copy of a commitment value of a transaction amount, a second random number encrypted using a public key of the first account, a third random number encrypted using a public key of the second account, one or more range proofs, and a set of values generated based on one or more selected random numbers. The consensus node then verifies a digital signature corresponding to the digitally signed copy using a public key of the first account corresponding to a private key used to generate the digital signature. It also updates the balance of the first account and a balance of the second account based on the amount of the balance transfer if the first random number, the second random number, and the third random number are the same.

Abstract: Implementations of the present disclosure include receiving, from a first account, a digitally signed copy of a commitment value of a first amount of a transaction amount generated based on a first random number, the first amount of the balance transfer and the first random number encrypted using a public key of the first account, a second amount of the balance transfer and a second random number encrypted using a public key of the second account, and a set of values generated based on one or more selected random numbers. The first account determines if the first amount and the second amount are the same and if the first random number and the second random number are the same based on the set of values, and updates the balance of the first account and a balance of the second account based on the first amount of the balance transfer.

Abstract: Implementations of the present disclosure include receiving, from a first account, a digitally signed copy of a plurality of notes, a commitment of a transaction amount of a transaction between the first account and a second account paid by at least a portion of the plurality of notes, a commitment of a change from deducting the transaction amount from a total value of the plurality of notes, and a zero-knowledge proof generated based on one or more selected random numbers. The first account determines that the total value of the plurality of notes equals the sum of the transaction amount and the change, validates the transaction, and updates the first account and the second account based on the plurality of notes, the transaction amount, and the change.

Abstract: Implementations of the present disclosure include receiving, by a consensus node of a blockchain, transaction data and a digital signature of the transaction data. The transaction data includes a commitment value, a random number, and a transaction amount to be transferred from one of a public account or a private account of the first user node to one of a public account or a private account of a second user node. The consensus node verifies the digital signature of the transaction data using a public key of the first user node. It then determines that the transaction amount is valid, if the commitment value is correct based on the random number and the commitment scheme, and the transaction amount is less than or equal to a balance of the one of the public account or the private account of the first user node before transfer of the transaction amount.