In a franking system, a postal security device (PSD) is used to account for postage dispensation, and generate digital signatures for inclusion in postage indicia to authenticate same. In accordance with the invention, the PSD includes multiple crypto processors which participate in franking transactions and generate the digital signatures in a multiplexed manner. Each crypto processor verifies the accounting of postage dispensation leading to and including the transactions in which the crypto processor participates. In addition, the crypto processors re-create transaction records and store them therein in a distributed manner.