Method and apparatus for ensuring debiting in a postage meter prior to its printing a postal indicia

In a postage meter having a vault subsystem and a printing subsystem, a method for ensuring that debiting occurs prior to printing of a postal indicia, the method comprising the steps of:

• a) separately generating a mutual session key in both the vault subsystem and the printing subsystem;
• b) using the mutual session key generated in both the vault subsystem and the printing subsystem for authenticating the vault subsystem to the printing subsystem;
• c) using the mutual session key generated in both the vault subsystem and the printing subsystem for authenticating the printing subsystem to the vault subsystem;
• d) performing debiting within the vault subsystem only subsequent to steps a), b), and c);
• e) sending an encrypted debit certificate from the vault subsystem to the printing subsystem;
• f) independently recreating the encrypted debit certificate in the printing subsystem;
• g) comparing the encrypted debit certificate to the recreated encrypted debit certificate to ascertain if a predetermined relationship exists therebetween which is indicative that the debiting of step (d) has occurred;
• and
• h) initiating printing of the postal indicia only upon determination of the existence of the predetermined relationship.