Abstract: This disclosure relates to blockchain-type data storage. In one aspect, a method includes receiving, by a database server, multiple second data records. Each second data record includes a first data record having a user identifier and a digital signature of the first data record. Hash values of the second data records are determined. In response to a blockchain-type block generation condition being satisfied, the database server determines two or more second data records to be written in a data block. An Nth data block that includes a hash value and a block height is generated. N is a sequence number of the Nth data block in a sequence of data blocks. When N>1, generating the Nth data block includes determining the hash value for the Nth data block based on the hash values of the two or more second data records and a hash value of a (N?1)th data block.

Abstract: Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for managing blockchain-based centralized ledger systems. One of the methods includes transmitting a timestamp request for a to-be-timestamped block of a blockchain at a time point to a trust time server by a ledger server in a blockchain-based centralized ledger system that stores data in the blockchain, the trust time server being associated with a trust time authority and independent from the blockchain-based centralized ledger system, the blockchain including a plurality of blocks storing transaction data, and disregarding the timestamp request in response to determining that a predetermined time period has lapsed after the time point and that there has been no reply to the timestamp request from the trust time server.

Abstract: Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for managing blockchain-based centralized ledger systems. One of the methods includes transmitting individual timestamp requests for to-be-timestamped blocks in a blockchain to a trust time server independent from a blockchain-based centralized ledger system that stores data in the blockchain, the blockchain including a plurality of blocks storing transaction data, receiving respective timestamps and associated signatures for the to-be-timestamped blocks from the trust time server, and storing information of the respective timestamps and associated signatures for the to-be-timestamped blocks in respective timestamped blocks in the blockchain, any adjacent two of the timestamped blocks in the blockchain being anchored with each other.

Abstract: Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for managing blockchain-based centralized ledger systems. One of the methods includes: transmitting a timestamp request for a to-be-timestamped block in a blockchain to a trust time server by a ledger server in a centralized ledger system that stores data in the blockchain, the trust time server being associated with a trust time authority and independent from the centralized ledger system, the blockchain including a plurality of blocks storing transaction data, receiving a timestamp and associated signature for the to-be-timestamped block from the trust time server by the ledger server, and storing information of the timestamp and the associated signature for the to-be-timestamped block in the blockchain by the ledger server.

Abstract: Disclosed herein are methods, systems, and apparatus, including computer programs encoded on computer storage media, for managing blockchain-based centralized ledger systems. One of the methods includes: transmitting a timestamp request for a to-be-timestamped block in a blockchain to a trust time server by a ledger server in a centralized ledger system that stores data in the blockchain, the trust time server being associated with a trust time authority and independent from the centralized ledger system, the blockchain including a plurality of blocks storing transaction data, receiving a timestamp and associated signature for the to-be-timestamped block from the trust time server by the ledger server, and storing information of the timestamp and the associated signature for the to-be-timestamped block in the blockchain by the ledger server.

Abstract: This disclosure relates to blockchain-type data storage. In one aspect, a method includes receiving, by a database server, multiple second data records. Each second data record includes a first data record having a user identifier and a digital signature of the first data record. Hash values of the second data records are determined. In response to a blockchain-type block generation condition being satisfied, the database server determines two or more second data records to be written in a data block. An Nth data block that includes a hash value and a block height is generated. N is a sequence number of the Nth data block in a sequence of data blocks. When N>1, generating the Nth data block includes determining the hash value for the Nth data block based on the hash values of the two or more second data records and a hash value of a (N?1)th data block.

Abstract: A computer-implemented method includes: receiving, by a server storing one or more blockchain ledgers, an authorization request from a client, in which the authorization request includes a service end identifier and a user identifier; generating, based on the authorization request, a database authorization instruction corresponding to the authorization request and a ledger identifier corresponding to the authorization request; authorizing a service end corresponding to the service end identifier as a user in a blockchain ledger corresponding to the ledger identifier; configuring a permission value of the user in the blockchain ledger, in which the permission value determines a degree to which the service end can operate the blockchain ledger; and sending authorization information including the user identifier and the ledger identifier to the service end.