1 / 20

Check Digit Schemes

Check Digit Schemes. Jerzy Wojdyło Southeast Missouri State University May 13, 2002. Common Error Patterns. POSTNET. Bar coded digits, 3 short, 2 long, weights 7 4 2 1 0 www.usps.com www.framed.usps.com/cpim/ftp/pubs/pub32.pdf Check equation (for n = 5, 9, 11) . POSTNET. POSTNET.

braima
Download Presentation

Check Digit Schemes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Check Digit Schemes Jerzy Wojdyło Southeast Missouri State University May 13, 2002

  2. Common Error Patterns

  3. POSTNET • Bar coded digits, 3 short, 2 long, weights 74210 • www.usps.com • www.framed.usps.com/cpim/ftp/pubs/pub32.pdf • Check equation (for n = 5, 9, 11)

  4. POSTNET

  5. POSTNET

  6. POSTNET Advantages • Detects all single errors, • Corrects single error (if corrupted digit is known) • Works for arbitrary length • Disadvantages • Transposition errors are undetected

  7. UPC • Bars and 12 digits UPC = [d1d2d3d4d5d6d7d8d9d10d11d12] w = [3 1 3 1 3 1 3 1 3 1 3 1 ] • Check equation • www.uc-council.com/checkdig.htm • www.upcdatabase.com

  8. UPC

  9. UPC • Advantages • Detects all single errors • Corrects single error (if corrupted digit is known) • Works for arbitrary length • Disadvantages (does not detect) • Jump transpositions • Adjacent transpositions ab ba if |a - b| = 5

  10. EAN • Bars and 13 digits EAN=[d1d2d3d4d5d6d7d8d9d10d11d12d13] w =[ 1 3 1 3 1 3 1 3 1 3 1 3 1 ] • Check equation • Advantages/disadvantages same as UPC • www.ean-int.org

  11. EAN

  12. Credit Cards

  13. Credit Cards • Check digit algorithm(s) • MOD 10 • Luhn Formula • IBM Check • Permutation Check • All do the same • Hans Peter Luhn (1896-1964) • Worked for IBM since 1941 • Example (Excel)

  14. Credit Cards • Advantages • Detects all single errors • Corrects single error (if corrupted digit is known) • Works for arbitrary length • Disadvantages (does not detect) • Jump transpositions • Adjacent transpositions 09  90 and 90  09

  15. ISBN • www.ISBN.org • Ten “digits” and three dashes (-) d1d2d3d4d5d6d7d8d9d10 d1,…, d9 = {0, 1, …, 9}; d10 ={0, …, 9, X=10} • Check equation

  16. ISBN 407=11·37

  17. ISBN • Advantages • Detects all single errors • Corrects single error (if corrupted digit is known) • Detects all transposition errors (!!) • Disadvantages • Works for bounded length (≤ 10) • Additional symbol X

  18. Other • US Postal Money Orders • MOD 9 arithmetic • Airline Tickets • MOD 7 arithmetic • Electronic Funds Transfer • MOD 10, weights [3 7 1 3 7 1 3 7 1] • Verhoeff’s Check Digit Scheme • German DM • Dihedral Group D5 multiplication

  19. The End If you blinked and missed it, go to www2.semo.edu/jwojdylo/research.htm

More Related