Method for verifying digital franking notes

A method for verifying postage indicia generated in customer systems using a data key and applied onto mailpieces, each postage indicium containing decrypted cryptographic information used for verifying the postage indicium, said method comprising:

• generating the data key in a value transfer center and transmitting the data key to a central payment assurance system,
• transmitting the data key from the central payment assurance system to local payment assurance systems and importing the data key in the local payment assurance systems,
• transmitting a result of the importing step from the local payment assurance systems to the central payment assurance system and to the value transfer center,
• after the data key has been successfully imported into essentially all local payment assurance systems, the value transfer center issuing the data key to the customer systems for producing the postage indicia, and
• verifying the postage indicia by decrypting the cryptographic information using the data key in the local payment assurance systems.