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Key Encryption in AWS HSM and PCI DSS Compliance (Requirement 3)

  • Writer: Nabu
    Nabu
  • Dec 23, 2024
  • 4 min read

In today's digital landscape, the protection of sensitive data is crucial, especially in the payment card industry. AWS Hardware Security Modules (HSM) are commonly used for key encryption, providing a secure and compliant solution to protect sensitive data, including cardholder data. This is a critical aspect for businesses seeking to achieve PCI DSS compliance.



What is Key Encryption and Why is it Important?


Key encryption involves securing cryptographic keys (used for data encryption) to ensure that unauthorized parties cannot access or misuse sensitive data. When dealing with cardholder data, PCI DSS Requirement 3 mandates that sensitive information, like Primary Account Number (PAN), Card Verification Values (CVV), and expiration dates, be protected using strong encryption techniques.


AWS HSM provides a robust solution to manage encryption keys securely by ensuring that these keys are stored, protected, and used within the bounds of the highest security standards.



How AWS HSM Helps with Key Encryption


AWS CloudHSM is a fully managed hardware security module that allows customers to generate, store, and manage cryptographic keys. AWS HSMs offer a level of physical and logical security that ensures compliance with a variety of security standards, including PCI DSS.


  1. Key Storage and Protection:

    • AWS HSMs store keys in FIPS 140-2 Level 3 validated hardware devices, ensuring that cryptographic operations (such as key generation, signing, and encryption) occur within the secure boundary of the hardware, making it virtually impossible for unauthorized users to access the keys.

  2. Separation of Keys:

    • Key-encrypting keys (KEKs) are stored separately from the data-encrypting keys (DEKs). AWS HSM ensures that the KEKs are used to protect DEKs and are not exposed to unauthorized access, providing an additional layer of protection for sensitive data.

  3. Encryption of Sensitive Data:

    • AWS HSM can be configured to encrypt cardholder data stored in systems, databases, or files. With AWS HSM, businesses can ensure that data is encrypted both at rest (when stored) and in transit (when being transmitted), complying with PCI DSS requirements.

  4. Key Management:

    • AWS provides key management tools integrated with HSM to ensure proper lifecycle management of cryptographic keys. This includes automated key rotation, lifecycle tracking, and access logging, which are essential for maintaining PCI DSS compliance.



Compliance with PCI DSS Requirement 3


PCI DSS Requirement 3 focuses on the protection of stored account data, specifying that sensitive data, including cardholder data (CHD), must be encrypted using strong encryption methods. The specific requirements for key management include:


  1. Requirement 3.4: Encrypt stored cardholder data using strong cryptography and security protocols.

  2. Requirement 3.6: Maintain strict control over cryptographic keys, including limiting access to the fewest custodians necessary, storing keys separately, and ensuring that key-encrypting keys are at least as strong as the data-encrypting keys they protect.

Here’s how AWS HSM helps in meeting these key requirements:

  1. Encryption and Key Management: AWS HSM supports FIPS 140-2 Level 3 compliance for key management, which is a requirement under PCI DSS. It ensures that cryptographic keys used for encrypting cardholder data are stored securely and are only accessible to authorized personnel.

  2. Key Separation and Control: As per PCI DSS Requirement 3.6, AWS HSM helps maintain the separation of key-encrypting keys from data-encrypting keys, ensuring that keys are stored securely in the fewest possible locations and that access is strictly controlled.

  3. Key Rotation and Expiry: AWS HSM can automate the process of rotating encryption keys at regular intervals, ensuring compliance with the PCI DSS requirement that keys should be refreshed periodically to reduce the risk of compromise.



Key Features of AWS HSM for PCI DSS Compliance


  • FIPS 140-2 Level 3 Validation: AWS HSM is certified under FIPS 140-2 Level 3, meeting the stringent security requirements for cryptographic modules, which is essential for meeting PCI DSS compliance.

  • Separation of Duties: AWS HSM allows businesses to implement the principle of least privilege by limiting access to cryptographic keys and ensuring that only authorized personnel can manage them.

  • Key Management Integration: With AWS Key Management Service (KMS) and CloudHSM integration, users can manage and control encryption keys, track their usage, and ensure that key policies align with PCI DSS requirements.

  • Automated Key Rotation: AWS HSM supports the automated rotation of keys, reducing the risk of key compromise and maintaining compliance with PCI DSS key management requirements.

  • Compliance Audits: AWS HSM logs all cryptographic operations and key usage, providing audit trails required for PCI DSS audits. These logs can be reviewed to ensure that key management practices are being followed correctly.



How to Be Compliant to PCI DSS Requirement 3 with AWS HSM


To ensure PCI DSS compliance with AWS HSM, follow these steps:


  1. Implement Strong Encryption: Use AWS HSM to manage and store encryption keys for cardholder data, ensuring that all sensitive information is encrypted both at rest and in transit.

  2. Ensure Separation of Keys: Store key-encrypting keys separately from data-encrypting keys within AWS HSM to maintain the integrity and security of sensitive data.

  3. Limit Key Access: Ensure that access to cryptographic keys is restricted to the minimum number of custodians necessary, and that all key management activities are logged for audit purposes.

  4. Regularly Rotate Keys: Implement automated key rotation policies using AWS HSM to comply with PCI DSS’s requirement for regular key changes to minimize risks.

  5. Conduct Annual Audits: Regularly review and audit key management processes and ensure that AWS HSM logs are available for audits to verify compliance with PCI DSS.



Conclusion


AWS HSM provides a robust, secure, and compliant solution for managing cryptographic keys in a way that meets PCI DSS Requirement 3. By using AWS CloudHSM, businesses can ensure that their encryption keys are securely managed, minimizing the risk of unauthorized access and data breaches. Additionally, AWS HSM’s FIPS 140-2 Level 3 certification, key rotation capabilities, and audit trail features ensure that businesses maintain compliance with PCI DSS and other industry regulations.

For more information on AWS CloudHSM and how it can help with PCI DSS compliance, visit the official AWS CloudHSM page.



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