Abstract: The present invention discloses a nanofiltration composite membrane, a preparation method and application thereof. The preparation method comprises: A) preparing 2D nano-material dispersion; B) first preparing a solution of a polymer material with a certain concentration, continuously adding a poor solvent under stirring conditions to subject the polymer material to chemical reaction to obtain a dispersion containing negatively charged polymer gel particles; C) subjecting the nano-material dispersion in step A) and the dispersion prepared in step B) to blending, membrane preparation and drying, and then placing the membrane into an alkaline solution with a certain concentration and pure water for soaking to obtain a nanofiltration composite membrane. The nanofiltration composite membrane can efficiently remove heavy metal complex ions through the synergistic effect of pore size screening and charge repulsion.

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: 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.

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: A computer-implemented method for information protection comprises: determining one or more data inputs and one or more data outputs for a transaction, wherein the data inputs are associated with input data types respectively, and the data outputs are associated with output data types respectively; encrypting the input data types and the output data types; committing each of the encrypted input data types and the encrypted output data types with a commitment scheme to obtain corresponding commitment values; obtaining at least a parameter R based at least on the commitment values; and submitting the transaction to one or more nodes in a blockchain network with disclosure of the parameter R and without disclosure of the input data types and output data types for the nodes to verify consistency between the input data types and the output data types.

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: 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 this specification include traversing a world-state MPT in multiple iterations, and, at each iteration, for a current node of the world-state MPT, executing one of: marking the current node as an account node and storing an address of the current node in the address list, determining that the current node is an extension node, and moving to a next iteration of the traversal setting the current node to a node referenced by the extension node, and marking the current node as a transition node, and storing an address of the current node in the address list; creating a sub-tree of the world-state MPT based on the address list, a root node of the sub-tree including a root node of the world-state MPT, and one or more child nodes of the sub-tree corresponding to nodes of the world-state MPT having an address stored in the address list.

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: An example operation may include one or more of splitting an encrypted file into a plurality of file fragments, distributing the file fragments to a plurality of storing peers for storing the file fragments off-chain, splitting an encryption key used to encrypt the file into a plurality of key fragments, encrypting each key fragment using a public key of a different storing peer, and storing the respectively encrypted key fragments on the distributed ledger such that each encrypted key fragment is associated with the encrypted file.

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 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.

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 method for information protection comprises: determining one or more data inputs and one or more data outputs for a transaction, wherein the data inputs are associated with input data types respectively, and the data outputs are associated with output data types respectively; encrypting the input data types and the output data types; committing each of the encrypted input data types and the encrypted output data types with a commitment scheme to obtain corresponding commitment values; obtaining at least a parameter R based at least on the commitment values; and submitting the transaction to one or more nodes in a blockchain network with disclosure of the parameter R and without disclosure of the input data types and output data types for the nodes to verify consistency between the input data types and the output data types.

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 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.

Abstract: The present invention discloses a brain-computer interface method and system based on real-time closed loop vibration stimulation enhancement.

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 for information protection comprises: determining one or more data inputs and one or more data outputs for a transaction, wherein the data inputs are associated with input data types respectively, and the data outputs are associated with output data types respectively; encrypting the input data types and the output data types; committing each of the encrypted input data types and the encrypted output data types with a commitment scheme to obtain corresponding commitment values; obtaining at least a parameter R based at least on the commitment values; and submitting the transaction to one or more nodes in a blockchain network with disclosure of the parameter R and without disclosure of the input data types and output data types for the nodes to verify consistency between the input data types and the output data types.

Abstract: A computer-implemented method for information protection comprises: determining one or more data inputs and one or more data outputs for a transaction, wherein the data inputs are associated with input data types respectively, and the data outputs are associated with output data types respectively; encrypting the input data types and the output data types; committing each of the encrypted input data types and the encrypted output data types with a commitment scheme to obtain corresponding commitment values; obtaining at least a parameter R based at least on the commitment values; and submitting the transaction to one or more nodes in a blockchain network with disclosure of the parameter R and without disclosure of the input data types and output data types for the nodes to verify consistency between the input data types and the output data types.

Abstract: The present invention discloses a nanocomposite membrane for heavy metal rejection and a preparation method thereof. The nanocomposite membrane comprises a porous membrane prepared from a two-dimensional sheet material and a hydrophilic inorganic nanomaterial distributed between the sheets of the two-dimensional material. The effective pore size of the nanocomposite membrane under wet conditions is not greater than 1.2 nm. The static water contact angle of the nanocomposite membrane is not greater than 45°. The preparation method of the nanocomposite membrane comprises: adding reactants on both sides of a nanoporous membrane to carry out an interfacial synthesis reaction to obtain the nanocomposite membrane. The method is simple and controllable. Driven by lower pressure, heavy metal ions in water are rejected by a pore size screening function, thereby achieving the purpose of deep removal. The nanocomposite membrane can be used to quickly remove heavy metal ions from water.

Abstract: Implementations of this specification include traversing a world-state MPT in multiple iterations, and, at each iteration, for a current node of the world-state MPT, executing one of: marking the current node as an account node and storing an address of the current node in the address list, determining that the current node is an extension node, and moving to a next iteration of the traversal setting the current node to a node referenced by the extension node, and marking the current node as a transition node, and storing an address of the current node in the address list; creating a sub-tree of the world-state MPT based on the address list, a root node of the sub-tree including a root node of the world-state MPT, and one or more child nodes of the sub-tree corresponding to nodes of the world-state MPT having an address stored in the address list.