Overview#Enciphered PIN is verified on-line (000010b) This Cardholder Verification Method is common for debit and credit card products used in unattended environments, when they are implemented with the magnetic stripe technology.
The EMV also accepts this method for chip-based card products. The cardholder types his or her PIN in the terminal's PIN pad. The terminal encrypts it using a symmetric Encryption mechanism. The IH receives this cryptogram, decrypts it in a secure module, which computes a PIN image control value that is compared against a witness value kept in the cardholder database, referred to as the PIN image stored value.
One reason for keeping this CVM for EMV ¢ chip products could be that there are issuers that do not trust the transmission in clear of the cardholder's PIN on the interface between the terminal and the chip card. The terminal implementing this CVM has to be equipped with an on-line PIN pad, which is a tamper resistant device that ensures that the PIN of the cardholder never leaves the PIN pad in clear, but just in an encrypted form.
Fallback or Fallback Transaction The term used for the scenario when a transaction is initiated between a chip card and a chip terminal but chip technology is not used and the transaction is completed via magnetic stripe or key entry.
There are multiple reasons this could occur such as an inoperative or malfunctioning chip/chip reader, improper use or a counterfeit card.