To store Customer Card information legally and securely, businesses must use advanced encryption or tokenisation to protect Cardholder data, ensuring that sensitive information is never retained after Authorisation. This Process is strictly governed globally by the Payment Card Industry Data Security Standard (PCI DSS), a mandatory set of security frameworks established by major Card networks to prevent data breaches and financial Fraud.

Credit Card Fraud is a serious and prevalent issue: in the United States, for example, 61% of credit Cardholders have been victims of Fraud. For businesses, the safe storage of Customer Card data is an important safeguard against Fraud.

What's in this article?

• How does Card storage work?
  
• What is PCI DSS compliance?
  
• PCI requirements for Card storage
  
• Best practice for Card storage
  
• Card storage challenges and solutions
  
• How Stripe can help
  

How does card storage work?

Card storage refers to businesses’ retaining customer payment card information, including credit and debit card numbers and associated identifying details. The four categories of data that businesses typically store are the cardholder name, primary account number (PAN), expiry date, and service code.

Businesses can choose from a variety of systems for card storage, and these typically involve components such as dedicated data storage systems, encryption and tokenisation techniques, and data loss prevention (DLP) tools.

Managing payment credentials internally exposes an organisation to severe legal liabilities, costly security audits, and potential brand damage if a breach occurs. Because of that, modern digital commerce isolates sensitive financial data using a three-part framework that transfers the risk away from the business’s internal network:

• Interception: Secure text fields (like iFrames) embed directly onto the checkout page, intercepting raw card data at the moment of entry so it completely bypasses the business’s web servers.

• Tokenisation: The payment processor locks the real card details inside an off-site, heavily fortified digital vault and generates a randomised, unhackable placeholder string called a token.

• Storage: The business saves only this harmless token inside its customer database, passing it back to the processor to safely authorise future transactions without ever handling raw financial data.

What is PCI DSS compliance?

The PCI DSS is a set of security standards that govern how businesses should accept, Process, store, and transmit credit Card information. This standard protects Cardholder data from Fraud and theft, and any organisation that handles credit Card transactions must adhere to it. The PCI DSS is managed by the Payment Card Industry Security Standards Council, which was founded by major credit Card companies such as Visa, Mastercard, American Express, Discover, and JCB. Complying with PCI DSS helps businesses reduce the risk of data breaches and ensure their Card transactions are secure.

Strictly speaking, PCI DSS is not a law. There aren't any Legal requirements for compliance. Instead, it’s an industry-developed security standard. However, looking at it purely as a voluntary industry recommendation is a critical mistake. PCI DSS functions as a mandatory contractual requirement.

The private Legal requirements are written directly into the Merchant agreements and corporate Terms of Service that every Business must sign with Payment processors, acquiring banks, and Merchant networks before they can accept electronic payments. If you want to Process credit Cards, you are bound by contract to maintain these standards.

PCI requirements for card storage

The PCI DSS details requirements for businesses regarding card storage, such as:

• Limit data storage: Store only Cardholder data that is necessary for Business needs. Do not store sensitive authentication data after Authorisation, even if encrypted. This includes data such as the full magnetic stripe, Card validation code, or personal identification number (PIN)/PIN block.

• Protect Stored data: Encrypt all Stored Cardholder data including the PAN, which should be rendered unreadable anywhere it is Stored using methods such as cryptography.

• Limit data access: Access to Cardholder data should be limited to individuals whose jobs require such access. Implement a need-to-know policy that restricts access.

• Create unique IDs: Assign a unique ID to each person with computer access to Cardholder data. After a data breach, this helps track who accessed data.

• Protect physical locations: Protect the physical locations where Cardholder data is Stored. This includes measures such as surveillance, Restricted access to data storage areas, and secure storage systems.

• Set retention and disposal policies: Develop a data retention policy that deletes Cardholder data as soon as it’s no longer required. Delete that type of data, and ensure it is unrecoverable.

• Use encryption keys: Manage and implement the use of strong cryptography and security protocols such as Secure Sockets Layer (SSL) / Transport Layer Security (TLS) or Internet Protocol Security (IPSEC) to safeguard sensitive Cardholder data during transmission over open, public networks.

Best practices for card storage

Businesses can take many routes to adhere to PCI compliance requirements. These best practices will help businesses to protect their customers' card information and maintain PCI compliance in a way that protects the user experience:

• Minimise Cardholder data storage: Store only required Cardholder information for Recurring billing and avoid retaining sensitive data unless absolutely necessary. Use a specialised Application programming interface (API) for Customer payments without storing Cards. Reducing the amount of Stored data can minimise risk and simplify compliance efforts.

• Adopt advanced encryption standard (AES): Use AES with a 256-bit key for encryption when storing credit Card numbers in a database. This methodology aligns with current best practice and surpasses minimum compliance requirements.

• Implement end-to-end encryption (E2EE): Beyond basic encryption practices, deploy E2EE to safeguard Cardholder data from the point of Capture until it reaches the secure processing environment.

• Improve access control mechanisms: Use multifactor authentication and granular Role-based access controls to ensure only authorised personnel can access sensitive Cardholder data. Have a clear audit trail for all access and actions taken.

• Integrate DLP tools: Implement DLP strategies to monitor and control Data transfer, preventing unauthorised data exfiltration and ensuring Cardholder data is not improperly Stored or distributed.

• Conduct regular security tests: To proactively identify and remediate potential security weaknesses, conduct sophisticated penetration testing and vulnerability assessments beyond the standard PCI DSS requirements. Create a PCI checklist for developers.

• Consider advanced tokenisation techniques: Consider using dynamic tokenisation, in which tokens vary with each Transaction, to provide an additional layer of security and further reduce the usefulness of intercepted data.

• Employ automated compliance monitoring: Use automated tools to continuously monitor compliance with PCI DSS standards and promptly detect and address any deviations.

• Use a zero-trust architecture: Adopt a zero-trust security framework that assumes all users, even those within the organisation, could potentially compromise Cardholder data. Enforce strict verification and minimal access principles.

• Explore quantum-resistant cryptography tools: To protect against emerging threats posed by quantum computing, explore the Integration of quantum-resistant cryptographic algorithms.

• Develop a response plan: Have a plan for responding to security incidents. If a data breach occurs, you should be able to quickly identify the issue, contain the breach, and mitigate any potential damage.

Card storage challenges and solutions

Card storage is closely tied to many aspects of the customer experience, how products and services are accessed, and how the internal team manages its engagement with customer data. Even the best-designed card storage systems will create a considerable amount of complexity. Here are a few common challenges along with solutions:

Designing card storage that scales with transaction growth

• Challenge: As transaction volumes grow, it can be difficult to maintain high performance and PCI compliance. Scalability issues have the potential to affect customer experience and operational efficiency.
  
• Solution: Implement distributed database architectures that can handle high read/write throughputs while maintaining data consistency and compliance. Use elastic cloud-based solutions that can respond dynamically to fluctuating demand and maintain performance without compromising security.
  

Modernising legacy systems while maintaining PCI compliance

• Challenge: Many organisations use legacy systems that are not designed to meet PCI DSS standards. This can create compliance and security gaps.
  
• Solution: Use data abstraction layers or service-oriented architectures to encapsulate legacy systems, minimising direct access to Cardholder data. Consider replacing or modernising legacy systems over time using microservices or containerisation to improve agility and compliance.
  

Managing cross-border card data and regional privacy requirements

• Challenge: Different regions have different Data protection regulations, and compliance requirements increase for businesses when they store Cardholder data across borders.
  
• Solution: Implement data residency solutions that Process and store data in compliance with local regulations. Use geolocation-based data storage and processing to automatically route and store data according to the Cardholder’s Location and in adherence to regional compliance requirements.
  

Defending against advanced security threats

• Challenge: Because attackers are continually changing tactics, organisations must fight against increasingly sophisticated cyberattacks and advanced persistent threats (APTs) that can bypass conventional security measures.
  
• Solution: Adopt a layered security approach that includes advanced threat detection and response mechanisms such as AI-driven behavioural analytics to identify and mitigate threats in real time. Regularly update incident response and disaster recovery plans to address new types of cyberthreats.
  

Staying compliant as PCI DSS standards change

• Challenge: PCI DSS standards and related regulatory requirements are continually changing, and staying compliant can be an ongoing challenge.
  
• Solution: Establish a continuous compliance monitoring programme that uses automated compliance tracking and Reporting tools. Engage in proactive industry forums and collaborations to stay ahead of emerging standards and incorporate best practice into your compliance strategy.
  

Ensuring accurate, consistent card data across systems

• Challenge: It can be difficult to ensure the integrity and consistency of Cardholder data across a variety of systems and storage environments, especially in distributed architectures.
  
• Solution: Implement strong data governance frameworks, and use data quality management tools that maintain data accuracy and consistency. Use data synchronisation and replication techniques that adhere to atomicity, consistency, isolation, and durability (ACID) properties to maintain data integrity.
  

How Stripe can help

Working with Stripe can help businesses reduce the burden of PCI DSS compliance. By processing payments through Stripe, businesses do not handle sensitive card data directly. Instead, Stripe uses a variety of advanced security features to protect payment data, which reduces the scope of a business’s compliance responsibilities. Stripe is a certified PCI Service Provider Level 1, the highest level of PCI compliance, and handles the majority of card data security tasks. These Stripe features keep cardholder data safe while helping businesses stay PCI compliant:

• Tokenisation: Stripe’s tokenisation service replaces sensitive card details with unique identifiers (tokens), which can be safely stored and used for transactions without exposing card details.

• E2EE: Stripe encrypts all sensitive data from the point of capture until it is processed within its secure environment. This end-to-end encryption minimises the risk that data will be intercepted during transmission.

• Scalability: Stripe’s infrastructure is built on a cloud platform designed to handle large volumes of transactions without compromising performance. Businesses can scale their operations without worrying about maintaining compliance and security standards.

• Integration with modern and legacy systems: Stripe offers extensive application programming interface (API) support, which makes it easy to integrate with modern and legacy systems. This flexibility helps businesses modernise their payment processing without the need for extensive overhauls of existing systems.

• Continuous monitoring and updates: Stripe continuously monitors its systems for threats and regularly updates its security measures to tackle emerging vulnerabilities. Security features include machine learning algorithms that detect and prevent fraud.

• Global compliance: Stripe operates globally and can help businesses deal with the complexities of data residency and regional compliance across borders.

• Data governance: Stripe’s infrastructure supports data integrity and consistency.

By relying on Stripe to manage most of the responsibility regarding secure card storage, data encryption, compliance, and scalability, businesses can spend more time on core operations. Learn more about Stripe Billing’s security standards.