United States Patent ti9i
Ehrat
[ii] 3,990,558 [45] Nov. 9, 1976
[54] METHOD AND APPARATUS FOR
PREPARING AND ASSESSING PAYMENT
DOCUMENTS
[75] Inventor: Kurt Ehrat, Zurich, Switzerland
[73] Assignee: Gretag Aktiengesellschaft, Zurich, Switzerland
[22] Filed: Oct. 7, 1974
[21] Appl. No.: 512,999
[30] Foreign Application Priority Data
Oct. 8, 1973 Germany 2350418
[52] U.S. Ci 194/4 R; 194/DIG. 26;
235/61.7 B; 340/149 R
[51] IntCl.2 G07F 1/06; G07D 7/00
[58] Field of Search 194/4 R, 4 A, 4 B, 4 C,
194/4 D, 4 E, 4 F, 4 G, DIG. 9 B; 235/61.7 B; 340/147 R, 149 R, 149 A
[56] References Cited
UNITED STATES PATENTS
3,487,905 1/1970 James 194/DIG. 9 B
3,570,643 3/1971 Maierhofer 194/DIG. 9 B
3,648,020 3/1972 Tateisi et al 194/DIG. 9 B
3,655,946 4/1972 Morita et al 194/DIG. 9 B
3,697,729 10/1972 Edwards et al 194/DIG. 9 B
3,845,470 10/1974 Schuller 340/149 R X
Primary Examiner—Robert B. Reeves
Assistant Examiner—Joseph J. Rolla
Attorney, Agent, or Firm—Pierce, Scheffler & Parker
[57] ABSTRACT
A method and apparatus is described for preparing and assessing machine readable payment documents such as bank or postal checks to avoid fraud. The checks are prepared by enciphering the serial number and the amount for which the check is made out with secret code data to provide a crypto number which is printed on the check with the serial number and the amount. The check is assessed as valid by reading out the printed data and enciphering the amount and serial number with the same secret code data as used when preparing the check to provide a crypto number which is compared with the crypto number read from the check. If the two crypto numbers are the same the check is assessed as valid.
The crypto number can be derived from additional data such as the credit card number of the person making out the check, the time and date and the number of the machine preparing the document.
8 Claims, 4 Drawing Figures
