DE55 - Cryptogram (Tag 9F27)

Data Element 55 (DE55) typically contains various components that provide specific information about a financial transaction, especially in the context of credit card processing. 

Today we will learn one of the important components of DE55. The Cryptogram (Tag 9f27)

The Cryptogram (Tag 9F27) plays a crucial role in the security of card transactions, particularly in EMV (Europay, Mastercard, Visa) chip card transactions. Here's an explanation of its role in the card transaction lifecycle:



1. Creation of Cryptogram:- The Cryptogram is generated by the chip on the EMV payment card during the transaction process. - It's created based on various data elements, including transaction details, card data, and a secret cryptographic key stored on the chip. 

2. Purpose of Cryptogram:- The primary purpose of the Cryptogram is to ensure the authenticity of the card and the integrity of the transaction data. - It helps prevent fraud by providing a unique code for each transaction, making it difficult for attackers to replicate or tamper with transaction data. 

3. Flow of Cryptogram:- The Cryptogram is generated by the chip on the payment card and sent to the card's application (e.g., credit or debit application) during the transaction. - It is typically included in the data that flows between the card and the point-of-sale (POS) terminal or card reader. - The POS terminal or card reader can then use the Cryptogram to verify the authenticity of the card and the transaction. 

4. Verification at the Terminal:- The POS terminal or card reader verifies the Cryptogram by using the same cryptographic key that was used to generate it. - If the Cryptogram is valid, it indicates that the card is genuine, and the transaction data has not been tampered with.

5. Authorization Request:- After verifying the Cryptogram, the POS terminal sends an authorization request to the card issuer (usually a bank) to approve the transaction. - The Cryptogram is often included in this request to provide assurance to the issuer that the transaction is legitimate.

6. Issuer Verification: - The card issuer receives the authorization request, including the Cryptogram. - The issuer can use the Cryptogram to validate the transaction's authenticity before approving or declining it.

In summary, the Cryptogram is a cryptographic code generated by the EMV chip on a payment card during a transaction. It serves to verify the authenticity of the card and ensure the integrity of transaction data. It flows between the card, the POS terminal, and the card issuer, helping to prevent fraud and enhance transaction security throughout the card transaction lifecycle.

Location: Mumbai, Maharashtra, India

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