ARQC/ARPC Generator

EMV cryptograms are security values generated during EMV chip card transactions to authenticate the card and transaction data. They play a crucial role in preventing card fraud.

Types of EMV Cryptograms:

• ARQC (Authorization Request Cryptogram): Generated by the card during online authorization
• ARPC (Authorization Response Cryptogram): Generated by the issuer in response to an ARQC
• TC (Transaction Certificate): Generated by the card when a transaction is approved
• AAC (Application Authentication Cryptogram): Generated by the card when a transaction is declined

Cryptogram Variants:

• CVN10: Visa's original cryptogram version
• CVN18: Visa's enhanced cryptogram version with session keys
• M/Chip: Mastercard's cryptogram implementation
• EMV Common Core: Standardized approach used by multiple schemes

Cryptogram Generation Process:

1. Card and terminal exchange transaction data
2. Card builds the CDOL (Card Data Object List) with transaction details
3. Card uses its unique keys to generate the cryptogram based on the transaction data
4. Terminal sends the cryptogram to the issuer for verification
5. Issuer validates the cryptogram and generates an ARPC response

Key Components:

• UDK (Unique Derivation Key): Card-specific key derived from the issuer master key
• ATC (Application Transaction Counter): Incremented by the card for each transaction
• UN (Unpredictable Number): Random value provided by the terminal
• CDOL (Card Data Object List): Transaction data elements used in cryptogram generation
• MAC (Message Authentication Code): The resulting cryptogram value

EMV cryptograms provide strong transaction security by cryptographically binding the card, terminal, and transaction details together, making it extremely difficult to create fraudulent transactions.