Glossary
3RI Payment
The EMV 3-D Secure request for information. It is an EMVCo term for the EMV 3-D
Secure service that can check a BIN without performing a complete
authentication.
3-D Secure
Security protocol for online credit card and debit card
transactions used by Visa Secure, Mastercard Identity Check, American
Express SafeKey, JCB J⁄Secure, Diners Club ProtectBuy, Discover
ProtectBuy, China UnionPay, and Elo.
AAV
Account Authentication Value. A unique 32-character transaction token for a
3-D Secure transaction. For Mastercard Identity Check, the AAV is named the
UCAF. For Visa Secure, the AAV is named the CAVV.
acquirer
The financial institution that accepts payments for products or services on behalf of
a merchant. Also referred to as the acquiring bank. This bank accepts or acquires
transactions that involve a credit card issued by a bank other than itself.
acquirer BIN
An eight-digit number that uniquely identifies the acquiring bank. Every
participating acquirer has a different acquirer BIN. The Mastercard BIN starts with
5 and the Visa BIN starts with 4.
acquirer processor
Processor that provides credit card processing, settlement, and services to merchant banks.
ACS
Access Control Server. The card-issuing bank’s host for the
payer authentication data.
ACS URL
The URL of the Access Control Server of the card-issuing bank that is returned in the
response to the request to check enrollment. You send the PAReq to this URL so that
the customer can be authenticated.
American Express
A globally issued card type that starts with 3 and which is identified as card type
003. These cards participate in a card authentication service (SafeKey) provided by
EMV 3-D Secure.
authentication result
Raw data sent by the card issuer that indicates the status of authentication. You do
not need to pass this raw data into the authorization.
Base64
Standard encoding method for data transfer over the internet.
BIN
Bank Identification Number. The eight-digit number that identifies the card
issuer.
CAVV
Cardholder Authentication Verification Value. A Base64-encoded string sent back with Visa
Secure-enrolled cards that specifically identifies the transaction with
the issuing bank and Visa. Standard for collecting and sending AAV data
for Visa Secure transactions. See AAV.
CAVV algorithm
The method used to generate the CAAV value.
Compra Segura
Trademarked name for the Elo card authentication service.
CVV
Card Verification Value. Security feature for credit cards and debit cards. This
feature consists of two values or codes: one that is encoded in the magnetic strip
and one that is printed on the card. Usually, the CVV is a three-digit number on the
back of the card. The CVV for American Express cards is a 4-digit number on the
front of the card. CVVs are used as an extra level of validation by issuing
banks.
Diners Club
A globally issued card type whose numbers start with a 3 or a 5. Diners Club cards
are identified as card type 005. These cards participate in a card authentication
service (ProtectBuy) provided by 3-D Secure.
Directory Servers
The Visa and Mastercard servers that are used to verify
enrollment in a card authentication service.
Discover
Primarily, a U.S. card type starting with a 6. Discover cards are identified as card
type 004. These cards participate in a card authentication service (ProtectBuy)
provided by 3-D Secure.
ECI (ECI Raw)
The numeric commerce indicator that indicates to the bank
the degree of liability shift achieved during payer authentication
processing.
E-Commerce Indicator
Alpha character value that indicates the transaction type,
such as MOTO or INTERNET.
Elo
A globally issued card type starting with a 5. Elo cards are identified as card type
of 054. These cards participate in a card authentication service (Compra Segura)
provided by 3-D Secure.
Enroll
A type of transaction used for verifying whether a
card is enrolled in the Mastercard Identity Check or Visa Secure service.
HTTP
The Hypertext Transfer Protocol is an application protocol used for data transfer on
the internet.
HTTP POST request
POST is one of the request methods supported by the HTTP protocol. The POST
request method is used when the client sends data to the server as part of
the request, such as when uploading a file or submitting a completed
form.
HTTPS
Hypertext Transfer Protocol combines with SSL/TLS (Secure Sockets
Layer/Transport Layer Security) to provide secure encryption of data
transferred over the Internet.
issuer
The bank that issues the credit card.
J/Secure
The EMV 3-D Secure program of JCB.
JCB
Japan Credit Bureau. A globally issued card type starting with a 3. JCB cards are
identified as a card type of 007. These cards participate in a card authentication
service (J/Secure) provided by EMV 3-D Secure.
Maestro
A card brand owned by Mastercard that includes several debit card BINs within the
U.K. and in Europe. Merchants who accept Maestro cards online are required to use
Mastercard Identity Check, Mastercard’s card authentication service. Maestro cards
are identified as 024 and 042 card types. Note that many international Maestro cards
are not set up for online acceptance and cannot be used even if they participate in
a Mastercard Identity Check authentication program.
Mastercard
A globally issued card that includes credit and debit cards. These cards start with a
5. These cards are identified as card type 002 for both credit and debit cards.
These cards participate in a card authentication service (Mastercard Identity Check)
provided by 3-D Secure.
Mastercard Identity Check
Trademarked name for Mastercard’s payer authentication service.
MD
Merchant-defined Data that is posted as a hidden field to the ACS URL. You can use
this data to identify the transaction on its return. This data is used to match the
response from the card-issuing bank to a customer’s specific order. Although payment
card companies recommend that you use the XID, you can also use data such as an
order number. This field is required, but including a value is optional. The value
has no meaning for the bank and is returned to the merchant as is.
Merchant ID
Data that must be uploaded for the Mastercard and Visa card
authentication process for each participating merchant. The Merchant ID
is usually the bank account number or it contains the bank account
number. The data is stored on the Directory Servers to identify
the merchant during the enrollment check.
MPI
Merchant Plug-In. The software used to connect to Directory Servers and to decrypt the PARes.
PAN
Primary Account Number. Another term for the credit card number.
PAReq
Payer Authentication Request. Digitally signed Base64-encoded payer authentication
request message, containing a unique transaction ID that a merchant sends to the
card-issuing bank. Send this data without alteration or decoding. Note that the
field name has a lowercase “a” (PaReq), but the message name has an uppercase “A”
(PAReq).
PARes
Payer Authentication Response. A compressed, Base64-encoded response from the card-issuing bank.
This data is passed for validation.
PARes status
Payer Authentication Response status. One-character length
status passed back by Visa and Mastercard that is required data for
Asia, Middle East, and Africa Gateway authorizations.
processor
Financial entity that processes payments. Also see
acquiring processor
.ProofXML
This field contains the VEReq and VERes messages for merchant storage. Merchants can
use this data for potential chargeback repudiation.
ProtectBuy
Trademarked name for the Diners Club and Discover card
authentication services.
request ID
A 22- or 23-digit number that uniquely identifies each
transaction. Merchants should store this number for
future reference.
risk-based authentication
Risk-based authentication is provided by the card-issuing bank. The card-issuing bank
gathers a cardholder’s transaction data or leverages whatever data they have to
silently authenticate the cardholder based on the perceived degree of risk. They
base their risk assessment on factors such as cardholder spending habits, order or
product velocity, the device IP address, order amount, and so on.
SafeKey
Trademarked name for the American Express card authentication service.
SCMP API
A legacy name-value pair API that was superseded by the Simple Order API.
Simple Order API
An API, that provides three ways to access services: name-value pair (NVP), XML, and
SOAP.
TermURL
Termination URL on a merchant’s website where the
card-issuing bank posts the payer authentication response (PARes)
message.
UCAF
Universal Cardholder Authentication Field. A Base64-encoded string sent back with
Mastercard Identity Check enrolled cards specifically identifying the transaction
with the issuing bank and Mastercard. Standard for collecting and sending AAV data
for Mastercard Identity Check transactions. See also
AAV
.UCAF collection indicator
Value of
1
or 2
that indicates whether a Mastercard
cardholder has authenticated themselves.validate
A service that decodes and decrypts the PARes message to determine success. The
validate service returns the needed values for authorization.
VEReq
Verify Enrollment Request. Request sent to the Directory Servers to verify that a card is enrolled in a card authentication service.
VERes
Verify Enrollment Response. Response from the Directory Servers to the VEReq.
VERes enrolled
Verify Enrollment Response enrolled. One-character length
status passed back by Visa and Mastercard that is required data for
Asia, Middle East, and Africa Gateway authorizations.
Visa
A globally issued card that includes credit and debit cards. These card numbers start
with a 4. These cards are identified as card type 001 for both credit and debit
cards. These cards participate in a card authentication service (Visa Secure)
provided by EMV 3-D Secure.
Visa Secure
Trademarked name for Visa’s card authentication service.
XID
String used by both Visa and Mastercard, that identifies a specific transaction on
the Directory Servers. This string value should remain consistent throughout a
transaction’s history.