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Issuing

78min

Issuing focuses on issuing payment cards and provisioning mobile payment tokens. The following sections cover these issuing topics:

  • PIN and offset generation
  • EMV key generation and derivation
  • Mobile payment token issuance
  • CVV generation

PIN and offset generation

For both PIN generation methods described in this section, the issuing bank associates PINs with an algorithm based on a 3DES encryption key, referred to as a PIN Verification Key (PVK). A PIN, generated based on the customer's account or card number and the PIN Verification Key, is called the natural PIN.

In the past, issuers did not allow customers to select their PIN. Instead, the bank would send the natural PIN to customers in the mail and force them to use the designated PIN. Now, most banks allow customers to select their own PIN. This is done by taking the PIN Verification Key, customer account number, and the chosen PIN, then sending that to an HSM to compare the natural PIN against the customer-selected PIN and determine the difference. The difference is referred to as the PIN Verification Value for the VISA PVV method and the offset for the IBM 3624 method.

VISA PVV

The VISA PVV algorithm performs a multiple encipherment of a value, called the transformed security parameter (TSP), and an extraction of a 4-digit PVV from the ciphertext.

You can use the GVWW Excrypt command to generate a random VISA Working Key for use in the VISA Network.

IBM 3624 (Offsets)

The IBM 3624 algorithm generates an n-digit PIN based on account or person-related validation data. The assigned PIN length parameter specifies the length of the generated PIN.

You can use the GOFF Excrypt command to generate a PIN Offset for use in the IBM 3624 Network.

Common PIN and offset generation commands

This section contains PIN and offset generation commands for Excrypt, Standard, and International command sets:

Excrypt

Command

Description



GNOF

Generate New Offset



GOFC

Generate Offset of Clear PIN



GOFF

Generate PIN offset value



GPIN

Generate PIN (Diebold Method)



GPIN

Generate PIN (IBM 3624 Method)



GPIN

Generate PIN (Visa Method)



Standard

Command

Description



34

Generate Clear PIN and Offset



386

Generate MAC (DUKPT)



38C

Derive DUKPT Initial PIN Encryption Key



3D

Generate IBM 3624 Offset



3FA

Generate PIN and PVV



International

Command

Description



BK

Generate IBM 3624 PIN Offset



DE

Generate IBM PIN Offset



DG

Generate Visa PIN Verification Value (PVV)



EE

Derive PIN using the IBM Method



FW

Generate Visa PIN Verification Value (of a customer-selected PIN)



JA

Generate Random PIN



EMV key generation and derivation

Europay, Mastercard, and Visa created the EMV standard, a payment method based on a technical standard for smart payment cards, payment terminals, and ATMs that can accept them.

EMV cards are smart cards, also called chip cards, which store their data on integrated circuit chips (ICCs), in addition to magnetic stripes for backward compatibility. These include cards that you physically insert (or dip) into a reader and contactless cards that can be read over a short distance using near-field communication technology.

Payment cards that comply with the EMV standard are often called chip and PIN or chip and signature cards, depending on the authentication methods employed by the card issuer, such as a personal identification number (PIN) or digital signature.

Outside the United States, the chip and PIN process is more common. It requires a secret four-digit PIN code known only by the cardholder to validate the EMV payment, making it significantly more secure. In the U.S., companies have opted for issuing chip and signature cards, weighing the risk of fraudulent transactions against the desire to make the purchasing process as seamless as possible for consumers.

Common EMV key generation and derivation commands

This section contains EMV key generation and derivation commands for Excrypt, Standard, and International command sets:

Excrypt

Command

Description



EMVG

Generate Master Key



EMVK

Derive Key from Vendor Master Key and Derivation Data



EMVM

Generate/Verify MAC



GCIV

Generate a CVC IV



GDAC

Generate a Data Authenticode Code (DAC)



GDCV

Generate DCVC3



GEMC

Generate EMV ICC Certificate



GEMQ

Generate EMV Issuer CSR



GIDN

Generate an ICC dynamic number (IDN)



GOPC

Generate Offset and EMV PIN Change



GVDC

Generate a Dynamic CVV



OFPC

Perform EMV PIN Change Using Offset



SSAD

Sign Static Authentication Data with Issuer Private Key



Standard

Command

Description



352

EMV Message Authentication Code (MAC) Generation



354

Generate Smart Card Master Key



368

Create Limited Use Key (LUK)



International

Command

Description



KE

Generate an EMV Issuer CSR



KI

Derive ICC key and encrypt under KEK



KO

Generate an EMV ICC certificate and sign with issuer private key



KU

Generate Secure Message with Integrity and optional Confidentiality



Mobile payment token issuance

The pay brands (such as Google Pay, Apple Pay, Samsung Pay, and so on) govern mobile payment tokens. To issue mobile payment tokens to a device, the card issuer (such as Wells Fargo, Chase, Bank of America, and so on) must have a relationship with the particular pay brand to which it plans to issue the mobile payment token. Each pay brand has specific data structures and encryption methods required to communicate a token to a device, so the card issuer must support those methods for it to work.

Common mobile payment token issuance commands

This section contains mobile payment token issuance commands for the Excrypt command set:

Excrypt

Command

Description



GHMC

Generate HCE Mobile Cryptogram



GHMD

Generate HCE Magstripe Verification Value



GHMK

Generate HCE Mobile Keys



The Standard and International command sets do not support mobile payment token issuance.

Card Verification Value generation

A Card Verification Value (CVV) is similar to a PIN, except it is not a secret value. A CVV is generated based on a Card Verification Key (CVK). So the CVK is the base key, and the CVV value is based on that key and the customer account or card number.

Originally, CVV validated that a user has the original card and not a cloned card.

We have CVV generation and verification but not translation because it is not encrypted between the hops.

Common CVV generation commands

This section contains CVV generation commands for Excrypt, Standard, and International command sets:

Excrypt

Command

Description



CAAV

Calculate Account holder Authentication Value



GCAV

Generate CAVV



GCAV

Generate American Express (Amex) CSC Value



GCVC

Generate CVC and CVC2



GCVV

Generate CVV/CVC Value



GDDC

Generate Discover dynamic CVV



GVDC

Generate dynamic CVV



GIDN

Generate ICC dynamic number (IDN)



Standard

Command

Description



35B

Generate American Express (Amex) CSC Value



5D

Generate Card Verification Value (CVV)



International

Command

Description



CW

Generate Visa Card Verification Value (CVV)



RY

Generate Random CSCK



RY (Mode 3)

Generate Card Security Codes for CSCK





Updated 09 Sep 2024
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