The first six digits of the credit card number (including the initial MII digit) are known as the Issuer Identification Number (IIN). These identify the institution that issued the card to the card holder. The rest of the number is allocated by the issuer. Cards are issued by the issuer through an issuing network. The card number's length is its number of digits. Many credit card issuers print the first four digits of the IIN on their card, just beneath where the number is embossed, as an added security measure.
In the United States, IINs are also used in NCPDP pharmacy claims to identify processors, and are printed on all pharmacy insurance cards. IINs are the primary routing mechanism for real-time claims. Each processor has one or more IINs, which it divides into plans by using Group Number and Processor Control Number fields.
Online merchants may use IIN lookups to help validate transactions. For example, if the credit card's IIN indicates a bank in one country, while the customer's billing address is in another, the transaction may call for extra scrutiny.
|美国运通||34, 37[失效連結]||Yes||15||Luhn algorithm|
|Bankcard||5610, 560221-560225||No||16||Luhn algorithm|
|大来卡 Carte Blanche||300-305||Yes||14||Luhn algorithm|
|大来卡 enRoute||2014, 2149||No||15||no validation|
|大来卡 北美||54, 55||Yes||16||Luhn algorithm|
|发现卡||6011, 622126-622925, 644-649, 65||Yes||16||Luhn algorithm|
|镭射卡||6304, 6706, 6771, 6709||Yes||16-19||Luhn algorithm|
|Maestro||5018, 5020, 5038, 6304, 6759, 6761, 6762, 6763||Yes||12-19||Luhn algorithm|
|Solo||6334, 6767||No||16, 18, 19||Luhn algorithm|
|Switch||4903, 4905, 4911, 4936, 564182, 633110, 6333, 6759||No||16, 18, 19||Luhn algorithm|
|Visa Electron||4026, 417500, 4508, 4844, 4913, 4917||Yes||16||Luhn algorithm|
On November 8, 2004, MasterCard and Diner's Club formed an alliance. Cards issued in Canada and the United States start with 54 or 55 and are treated as MasterCards worldwide. International cards use the 36 prefix and are treated as MasterCards in Canada and the United States, but are treated as Diner's Club cards elsewhere. Diner's Club International's web site makes no reference to old 38 prefix numbers, and they can be presumed reissued under the 55 or 36 IIN prefix. Effective October 16, 2009, Diner's Club cards beginning with 30, 36, 38 or 39 have been processed by Discover Card.
Effective October 1, 2006, Discover began using the entire 65 prefix, not just 650. Also, similar to the Master Card/Diner's agreement, China Union Pay cards are now treated as Discover cards and accepted on the Discover network.
- ^ Card Security Features (PDF). American Express. January 2001 [2006-04-05].[失效連結]
- ^ American Express Fraud Prevention Handbook (PDF). 13. [2006-04-05].
- ^ Bankcard Association of Australia. [2006-04-05].
- ^ China UnionPay Cards. [2010-11-26].
- ^ MasterCard Diner's Club Alliance. [2006-04-05].
- ^ Diner's Club - Fraud Management. [2007-01-26].
- ^ Discover Network - IIN Range Update, 8.2 (PDF). September 2008 [2008-10-23].
- ^ Discover Network IIN Range Update, 9.2 (PDF). September 2009.
- ^ What To Do If Compromised: Visa Fraud Control and Investigations Procedures (PDF). 36. December 2008 [2010-01-09].
- ^ Discover Network - IIN Range Update, 9.1 (PDF). October 2008 [2009-01-28].