System and method for securely backing up and reliably retrieving vault data in a metering system that includes a host processor operatively coupled to a vault. Whenever a transaction is completed by the vault, the vault cryptographically signs the vault data, including ascending register, descending register and piece count and sends the cryptographically signed vault data to the host processor where it is stored in a data file assigned to the vault. Each storage of the cryptographically signed vault data is indexed to create a historical log of vault transactions. If the vault is lost or damaged so that vault data cannot be retrieved from the vault, the cryptographically signed vault data is retrieved from the host processor data file and verified.