Systems and methods for secure digital asset transactions. An offline system includes a custodian computer, digital asset accounts accessible by the custodian computer and a centralized ledger maintained by the custodian computer. The custodian computer is in communication with public ledger computers of a public ledger, and receives transaction data associated with digital assets from among entity computers. Each account is prefunded with digital asset funds. The custodian computer monitors a transaction parameter of the transaction data and, in accordance with the monitoring, generates a transfer instruction indicating transfer of funds between the first and second accounts, updates the centralized ledger responsive to the transfer instruction, and transfers the funds between the first and second accounts, responsive to the transfer instruction. The transfer instruction remains offline and is not transferred to the public ledger.