A Scalable and Universal Cross-ledger Protocol Designed for Business. OneLedger is an enterprise blockchain solution that is focused on bridging centralized enterprise technologies with emerging decentralized technologies such as Bitcoin and Ethereum. OneLedger provides an SDK and API to make coding easier than before. We have the concept of Business Modules that will allow developers to package sophisticated strategies. Basically, we are creating a general mechanism within the protocol to let blockchains map and transfer digital assets within OneLedger to run, exchange and support cross-chain transaction through side-chains. On the business layer of OneLedger, we offer a solution to bridge public chains and private chains which would encapsulate OneLedger into a small virtual network based on Business Modules. The network supports the private transactions inside of modules, and offers partial broadcasting transaction between modules or public transaction with whole network broadcasting.