Abstract: A cryptographic method where items, such as mail pieces, are verified for authenticity includes determining a predetermined number of items selected for verification during a given period and maintaining a count of the number of items verified. The predetermined number is compared with the number of items verified. The verification process may continue if a match occurs and may be stopped if a match does not occur. The verifier includes means for inputting data relating to an item to be verified and access counter means for counting the number of items verified.