ARPC and ARQC in EMV Transactions: Security in Payment Systems


EMV (Europay, Mastercard, and Visa) is a global standard for credit card processing, designed to enhance the security of card transactions. One crucial aspect of EMV transactions is the use of Authentication Response Cryptogram (ARPC) and Application Cryptogram (ARQC). These cryptographic elements play a pivotal role in ensuring the integrity and authenticity of the data exchanged during card-present transactions. In this article, we will delve into the significance of ARPC and ARQC in EMV, exploring how they contribute to a more secure payment environment.

Understanding ARPC:

Authentication Response Cryptogram (ARPC) is a dynamic cryptographic value generated during the transaction process. It serves as a proof of the legitimacy of the transaction and protects against various forms of fraud, including replay attacks. ARPC is created by the card issuer’s host system and is based on unique transaction data, such as the transaction amount, terminal data, and other transaction-specific information.

Key features of ARPC include:

  1. Dynamic Generation: ARPC is dynamically generated for each transaction, incorporating transaction-specific data. This dynamic nature adds an extra layer of security, as the value changes with each transaction.
  2. Verification at the Issuer End: The ARPC is sent along with other transaction data to the card issuer’s host system. Upon receiving the ARPC, the issuer’s system verifies its authenticity and validity before approving or declining the transaction.
  3. Protection Against Replay Attacks: By using dynamic data, ARPC prevents replay attacks where an attacker attempts to reuse transaction data to initiate unauthorized transactions.

Understanding ARQC:

Application Cryptogram ( ARQC ) is another essential component of the EMV transaction process. It is generated by the Integrated Circuit Card (ICC) or chip on the payment card. ARQC is derived from the issuer’s Application Transaction Counter (ATC), a unique transaction counter maintained by the card’s application.

Key features of ARQC include:

  1. Static Authentication: Unlike ARPC, which changes dynamically with each transaction, ARQC remains constant for a specific transaction until the card’s ATC is incremented. It provides a static authentication value for the current transaction.
  2. Verification at the Terminal End: The ARQC is sent to the terminal during the transaction, and the terminal verifies its authenticity. This process ensures that the transaction data received from the card is legitimate and has not been tampered with.
  3. Protection Against Counterfeit Cards: ARQC helps in preventing the use of counterfeit cards by ensuring that the transaction data is genuinely generated by the authentic chip on the card.

Implementing ARPC and ARQC in the EMV Process:

The implementation of ARPC and ARQC involves collaboration between the payment card, the terminal, and the card issuer. Here’s a step-by-step breakdown of how these cryptographic elements function within the EMV process:

  1. Transaction Initialization:
    • A cardholder inserts their EMV-enabled card into the chip card reader at the terminal to initiate a transaction.
  2. Card Authentication:
    • The terminal communicates with the card’s chip, initiating the authentication process.
    • The card generates the ARQC based on its Application Transaction Counter (ATC) and sends it to the terminal.
  3. Dynamic Data Inclusion:
    • The terminal collects transaction-specific data, including the transaction amount, terminal information, and other relevant details.
    • The card issuer’s host system uses this dynamic data to generate the ARPC.
  4. ARPC Transmission:
    • The ARPC, along with other transaction data, is sent from the terminal to the card issuer’s host system for verification.
  5. Issuer Verification:
    • The card issuer’s host system verifies the ARPC to ensure the legitimacy of the transaction.
    • If the ARPC is valid, the issuer approves the transaction, and the approval response is sent back to the terminal.
  6. Transaction Completion:
    • With the issuer’s approval, the terminal completes the transaction, and the cardholder can safely remove their card.

Advantages of ARPC and ARQC:

  1. Dynamic Security:
    • ARPC’s dynamic generation ensures that each transaction has a unique cryptographic value, making it challenging for attackers to reuse transaction data.
  2. Counterfeit Card Prevention:
    • ARQC, tied to the card’s Application Transaction Counter, helps prevent the use of counterfeit cards by providing a static authentication value.
  3. Protection Against Replay Attacks:
    • ARPC’s dynamic nature safeguards against replay attacks, where fraudsters attempt to replay previously intercepted transaction data.
  4. Enhanced Transaction Integrity:
    • The combined use of ARPC and ARQC significantly contributes to the overall integrity and authenticity of EMV transactions.

Challenges and Future Developments:

While ARPC and ARQC are effective in bolstering security, the landscape of payment fraud is dynamic. Continuous advancements in technology and evolving attack methods necessitate ongoing efforts to enhance security measures further.

Future developments may include the integration of additional layers of authentication, biometric verification, and the adoption of more advanced cryptographic algorithms to stay ahead of emerging threats.

In conclusion, the implementation of ARPC and ARQC in EMV transactions is a crucial step towards creating a secure and trustworthy payment environment. By employing dynamic and static authentication values, these cryptographic elements play a pivotal role in mitigating various forms of fraud, contributing to the ongoing evolution of secure payment systems. As the payment industry continues to innovate, staying vigilant and proactive in addressing emerging security challenges remains paramount.

Addressing Evolving Security Challenges:

As the payments landscape advances, the need for continuous improvement in security measures becomes increasingly evident. To address emerging challenges, industry stakeholders are exploring additional layers of security. Some potential avenues for enhancement include:

  1. Biometric Authentication:
    • Integrating biometric authentication methods, such as fingerprint or facial recognition, could add an extra layer of security to the transaction process. This would not only strengthen the verification process but also provide a more convenient and user-friendly experience for cardholders.
  2. Tokenization:
    • Tokenization involves replacing sensitive data, such as card numbers, with unique tokens. Implementing tokenization further reduces the risk of data breaches, as even if the token is intercepted, it cannot be used to initiate unauthorized transactions without the corresponding secure tokenization system.
  3. Enhanced Cryptographic Algorithms:
    • Continuous research into advanced cryptographic algorithms is crucial to staying ahead of potential threats. As computing power increases, updating encryption methods to more robust algorithms ensures the continued security of transactions.
  4. Real-time Fraud Detection:
    • Implementing real-time fraud detection systems that analyze transaction patterns and behaviors can help identify and prevent fraudulent activities immediately. Machine learning algorithms can adapt and evolve to detect new and sophisticated fraud patterns.

International Collaboration and Standards:

As the global nature of payments transcends borders, international collaboration is key to maintaining a unified front against fraud. Standardizing security protocols across regions and fostering information sharing between financial institutions and industry stakeholders contribute to a more resilient defense against global threats.

User Education and Awareness:

Empowering users with knowledge about secure transaction practices is a critical aspect of a comprehensive security strategy. Educating cardholders about the importance of protecting their PINs, reporting lost or stolen cards promptly, and being cautious about phishing attempts can significantly reduce the risk of fraud.


ARPC and ARQC represent fundamental components of the EMV framework, offering robust security features for card-present transactions. However, as the threat landscape evolves, the payments industry must adapt and innovate to stay one step ahead of potential attackers. By combining advanced technologies, international collaboration, and user education, the financial ecosystem can create a more secure environment for electronic transactions.

As we move forward, the commitment to enhancing security measures must remain unwavering. The collaborative efforts of industry stakeholders, continued research into cutting-edge technologies, and a focus on user education will collectively contribute to a future where electronic transactions are not only convenient but also consistently secure against evolving threats.