Abstract: A method and system for converting database applications into blockchain applications is disclosed. Multiple applications on different nodes can automatically perform global data consensus to prevent data conflicts using the embodiments described. One method involves monitoring databases as they is modified by database applications, to extract data operations from transaction logs, convert the data operations to a general format, and activate the smart contract on the blockchain to complete the data consensus check at multiple nodes. Each node monitors the blocks on blockchain and synchronizes the data back to database. In the case of conflicting data, the data is not able to pass consensus and synchronize with the other nodes in the blockchain. The local nodes automatically roll back when detecting invalid data.

Abstract: A method for generating fair and effective random numbers for smart contracts, which effectively mitigates certain problems associated with conventional methods while achieving verifiable and non-tamperable random number generation is disclosed. The concept behind the disclosed method treats miners as being not trustworthy, and presumes that the number of miners in the blockchain is limited. With sufficient motivation, miners can reach a consensus to manipulate the block. The goal is thus to create a verifiable fair Random Number Generator. Under this condition, as long as at least one of the parties to the smart contract is credible and does not misuse the confidential information, a trusted blockchain random number can be generated. After the last disclosure of the random number, the verification signature submitted by parties to the contract can be used to confirm that the random number calculation process is credible.

Abstract: A method for augmenting a database application with blockchain technology is disclosed. The method involves recording data modifications made by a database application into a corresponding database as well as on a blockchain for global consensus confirmation. This is done without changing the existing application architecture and with minimal code changes to the existing application. Records in the database requiring synchronization with the blockchain are subjected to consensuses voting, and unauthorized database changes are rolled back, thereby granting immutability and non-repudiation characteristics to a traditional database application. Records in databases are thus made globally consistent. An existing database application can be deployed on a blockchain without significantly modifying the code. Multiple applications can synchronize data through a common blockchain, which greatly simplifies building blockchain applications.