How to Achieve PCI DSS 4.0 Compliance for Payment Processing Systems

Payment processing systems handle billions of transactions and expose organizations to credential theft, data exfiltration, and regulatory penalties when controls fail. The Payment Card Industry Data Security Standard version 4.0 introduces customized implementation requirements, expanded continuous monitoring mandates, and stricter accountability for third-party risk, reshaping how enterprises architect and operate cardholder data environments.

Organizations that treat PCI DSS 4.0 compliance as a checklist exercise rather than an integrated security posture will face audit failures, expensive remediation cycles, and erosion of customer trust. This guide explains how security leaders and IT executives can operationalize the standard's new requirements, integrate compliance into existing governance frameworks, and maintain audit readiness without disrupting payment operations.

You'll learn how to scope your cardholder data environment accurately, implement continuous validation controls, establish defensible evidence workflows, and secure sensitive payment data in motion across email, file sharing, managed file transfer, web forms, and Application Programming Interfaces (APIs).

Executive Summary

PCI DSS 4.0 shifts the compliance model from static annual assessments to continuous validation, targeted risk analysis, and proactive evidence collection. The standard became active on March 31, 2024, with PCI DSS 3.2.1 retired on March 31, 2025, meaning all organizations must now operate under version 4.0 requirements.

Enterprises must demonstrate that security controls remain effective between audit cycles, that encryption and access policies adapt to evolving threats, and that every component involved in payment processing meets the same rigor. Security leaders who embed compliance workflows into operational tooling, automate evidence generation, and enforce zero-trust principles for data in motion reduce audit friction, minimize remediation costs, and accelerate detection of configuration drift or policy violations.

Organizations at all merchant levels—from Level 1 entities processing over 6 million transactions annually to Level 4 merchants handling fewer than 20,000 e-commerce transactions—benefit from automated evidence collection, immutable audit trails, and content-aware controls that secure cardholder data across all communication channels.

Key Takeaways

• PCI DSS 4.0 mandates continuous monitoring and targeted risk analysis, replacing point-in-time assessments with ongoing validation of encryption, access controls, and configuration baselines across the cardholder data environment (CDE).
• Accurate scoping of the CDE requires mapping every system, network segment, and third-party integration that stores, processes, or transmits payment card data, including indirect dependencies that increase attack surface.
• Organizations must implement immutable audit trails for all access to cardholder data, correlate activity logs with identity context, and retain evidence in tamper-proof formats to satisfy Qualified Security Assessor (QSA) requirements.
• Encryption alone does not satisfy PCI DSS 4.0 requirements; enterprises must enforce content-aware data loss prevention, automated key rotation, and session-level controls for sensitive data in motion.
• Third-party service providers and external integrations extend the compliance boundary, requiring contractual validation of PCI DSS adherence, continuous monitoring of shared data flows, and joint incident response planning.

Understanding the Scope and Intent of PCI DSS 4.0

PCI DSS 4.0 redefines compliance as a continuous state rather than a moment in time. The standard introduces customized implementation requirements that allow organizations to achieve security objectives through alternative controls, provided they document the risk analysis and rationale. This flexibility addresses enterprise complexity but demands mature governance processes and defensible decision logs.

The cardholder data environment includes any system component that stores, processes, or transmits cardholder data, as well as any component that connects to or can affect the security of that environment. Organizations frequently underestimate scope by excluding jump hosts, management interfaces, logging infrastructure, or third-party analytics platforms that indirectly access payment systems. Inaccurate scoping leads to unmonitored attack vectors and audit findings that require expensive remediation.

The standard now requires continuous validation of encryption, access controls, and configuration baselines. Enterprises must demonstrate that controls remain effective between assessments and that deviations trigger alerts and remediation workflows. This shift aligns compliance with operational security but requires integration between compliance management platforms, Security Information and Event Management (SIEM) systems, and identity governance tools.

PCI DSS 4.0 Timeline and Current State

Understanding the transition timeline and current compliance requirements:

• March 31, 2024: PCI DSS 4.0 became the active standard, with organizations able to use either version 3.2.1 or 4.0 during the transition period
• March 31, 2025: PCI DSS 3.2.1 officially retired—all organizations must now comply with version 4.0
• March 31, 2025: Requirements previously designated as "best practices" became mandatory
• Current State (2026): All organizations should be fully compliant with PCI DSS 4.0, with continuous monitoring and validation in place

Organizations still completing their transition to 4.0 should prioritize implementing continuous monitoring capabilities, automating evidence collection, and addressing any gaps identified during initial assessments.

Merchant Levels and Requirement Scaling

PCI DSS requirements apply to all merchants but scale based on transaction volume:

• Level 1 Merchants: Over 6 million transactions annually—most stringent requirements including mandatory annual on-site security assessments by QSAs, quarterly network scans by Approved Scanning Vendors (ASVs), and comprehensive attestations of compliance
• Level 2 Merchants: 1 to 6 million transactions annually—annual Self-Assessment Questionnaire (SAQ) or assessment by QSA, quarterly network scans, attestation of compliance
• Level 3 Merchants: 20,000 to 1 million e-commerce transactions annually—annual SAQ, quarterly network scans, attestation of compliance
• Level 4 Merchants: Fewer than 20,000 e-commerce transactions or up to 1 million total transactions annually—annual SAQ, quarterly network scans may be required by acquirer

All levels benefit from continuous monitoring, automated evidence collection, and securing cardholder data in motion, though implementation complexity scales with transaction volume and organizational size.

Scoping the Cardholder Data Environment Accurately

Scoping errors account for a significant portion of failed attestations. Organizations must map every network segment, application server, database instance, and middleware layer that interacts with cardholder data. This includes payment gateways, tokenization services, fraud detection engines, reporting databases, and backup systems.

Network segmentation reduces scope by isolating the CDE from general-purpose infrastructure. Effective segmentation requires firewall rules, virtual local area network policies, and intrusion detection systems that enforce boundary controls and log all traversal attempts. Segmentation does not eliminate compliance obligations but limits the number of systems subject to full PCI DSS requirements.

Third-party integrations extend the compliance boundary. Payment processors, hosted checkout pages, API gateways, and software-as-a-service platforms that access cardholder data must provide attestation of compliance. Organizations remain accountable for validating that third parties implement equivalent controls and notify customers of security incidents within agreed timeframes.

Documentation of scoping decisions must include network diagrams, data flow maps, and risk assessments that justify inclusion or exclusion of systems. QSAs evaluate scoping accuracy during audits and may expand scope if they identify undocumented dependencies or inadequate boundary controls.

Common Compliance Gaps and How to Address Them

Organizations frequently encounter PCI DSS violations in areas overlooked by traditional compliance programs:

• Scoping Errors: Excluding jump hosts, management interfaces, or logging systems that can access or affect the CDE.
  Solution: Conduct comprehensive network discovery, document all system interconnections, and review scope annually or when infrastructure changes.
• Data in Motion: Overlooking email attachments or file shares containing cardholder data that bypass monitored channels.
  Solution: Implement content-aware data loss prevention across all communication channels, including email gateways, file sharing platforms, and web forms.
• Third-Party Oversight: Failing to validate vendor attestations or monitor third-party access to cardholder data.
  Solution: Establish vendor risk management programs with continuous monitoring, annual attestation reviews, and contractual audit rights.
• Audit Trail Gaps: Incomplete logging or logs stored in mutable formats that can be altered after incidents.
  Solution: Implement immutable audit trails with cryptographic signing, centralized log aggregation, and tamper-proof storage.
• Key Management: Manual rotation processes that miss deadlines or lack cryptographic inventory documentation.
  Solution: Automate key lifecycle management with policy-driven rotation, maintain comprehensive key inventories, and integrate with secrets management platforms.

Self-Assessment Compliance Checklist

Organizations can evaluate their current PCI DSS 4.0 compliance posture:

• ☐ Cardholder data environment accurately scoped and documented with network diagrams
• ☐ Network segmentation implemented with boundary controls and penetration testing
• ☐ Continuous monitoring of encryption and access controls with automated alerts
• ☐ Immutable audit trails capturing all cardholder data access with user attribution
• ☐ Content-aware DLP preventing unauthorized transmission of Primary Account Numbers (PANs)
• ☐ Automated key rotation with comprehensive cryptographic inventory
• ☐ Third-party attestations validated and current with continuous monitoring
• ☐ Incident response procedures tested and documented with defined escalation paths
• ☐ Customized implementation approaches documented with risk analysis and QSA approval
• ☐ Configuration baselines established with automated drift detection and remediation

Understanding Customized Implementation Requirements

PCI DSS 4.0 allows organizations to use alternative controls that achieve security objectives through different means than prescribed requirements. This flexibility accommodates diverse technology environments but requires rigorous documentation.

What Qualifies as an Acceptable Alternative Control

• Meet the security objective of the original requirement
• Provide equivalent or greater security protection
• Include documented risk analysis justifying the alternative approach
• Maintain or reduce overall risk to the CDE
• Receive QSA approval during assessment

Documentation Requirements for Customized Approaches

• The specific requirement being addressed through customization
• Detailed description of the alternative control implementation
• Risk analysis demonstrating equivalent security
• Testing results proving effectiveness
• Ongoing monitoring and validation procedures
• Approval documentation from security leadership

How QSAs Evaluate Customized Implementations

• Completeness of risk analysis and threat modeling
• Technical effectiveness of alternative controls
• Evidence of ongoing monitoring and validation
• Comparison to defined approach security outcomes
• Documentation quality and maintenance processes

Common Scenarios for Customized Approaches

• Modern cloud architectures require alternative network controls
• Containerized environments need different segmentation strategies
• DevOps pipelines demand automated security validation
• Legacy systems cannot support prescribed technical requirements
• Innovative technologies offer superior security outcomes

Implementing Continuous Monitoring and Automated Evidence Collection

PCI DSS 4.0 requires organizations to detect configuration changes, unauthorized access attempts, and policy violations in near real time. Continuous monitoring replaces periodic vulnerability scans and manual log reviews with automated detection, correlation, and alerting workflows that integrate with security operations centers.

Encryption key management moves from annual rotation schedules to automated lifecycle management with policy-driven rotation triggered by key age, usage volume, or security events. Organizations must maintain cryptographic inventories that document key purpose, storage location, access permissions, and rotation history.

Access controls for cardholder data require multifactor authentication, least privilege enforcement, and session recording for privileged accounts. Organizations must correlate authentication logs with network traffic, file access, and database queries to establish attribution and detect anomalous behavior. Access reviews transition from quarterly manual processes to continuous validation using identity governance platforms that flag dormant accounts, excessive permissions, and orphaned credentials.

Audit preparation consumes significant security team resources when evidence exists in disparate systems and requires manual aggregation. Organizations that automate evidence collection reduce audit cycles from weeks to days and eliminate gaps caused by incomplete or inconsistent documentation.

Immutable audit trails capture every interaction with cardholder data, including file downloads, API calls, email transmissions, and database queries. Logs must include user identity, timestamp, source address, action taken, and result. Tamper-proof storage with cryptographic signatures ensures that logs remain admissible as evidence and satisfy assessor requirements for integrity.

Compliance mapping tools correlate security controls with specific PCI DSS requirements, generating reports that show which technical implementations satisfy each standard clause. These mappings accelerate assessor reviews and provide objective evidence that controls remain effective. Organizations should maintain version-controlled policy documents, control implementation guides, and test results that demonstrate ongoing adherence.

Configuration baselines establish approved settings for firewalls, databases, web servers, and payment applications. Automated scanning detects drift from baselines and triggers remediation workflows that restore compliant configurations or update baselines when approved changes occur.

What QSAs Expect During Assessments

Complete and Accurate Network Diagrams:

• All systems within scope clearly identified
• Network boundaries and segmentation points documented
• Data flows showing cardholder data movement
• Third-party connections and access points mapped

Data Flow Maps:

• Every location where cardholder data resides
• All channels through which data moves (APIs, file transfers, email)
• Processing stages from capture through storage and transmission
• Retention and disposal procedures

Evidence of Continuous Monitoring:

• Real-time alerting for configuration changes
• Automated detection of policy violations
• Trending data showing control effectiveness over time
• Not just point-in-time snapshots from assessment day

Immutable Audit Trails with Complete Attribution:

• Every access to cardholder data logged with user identity
• Cryptographic signing proving logs haven't been altered
• Centralized aggregation with long-term retention
• Integration with incident response workflows

Documentation of Customized Implementation Rationale:

• Detailed risk analysis for alternative controls
• Evidence that customized approach meets security objectives
• Ongoing validation and effectiveness testing
• Comparison to defined approach outcomes

Third-Party Validation and Monitoring Evidence:

• Current attestations of compliance from all service providers
• Contractual provisions for security obligations
• Evidence of continuous monitoring of third-party access
• Incident notification procedures and testing

Tokenization vs. Encryption: Strategic Considerations

Organizations should understand the differences and strategic implications:

Tokenization:

• Replaces cardholder data with surrogate values (tokens)
• Significantly reduces PCI DSS scope by removing actual cardholder data from systems
• Tokens are meaningless if intercepted or stolen
• Requires token vault infrastructure to map tokens back to real values
• Best for: Organizations wanting to minimize scope and compliance burden

Encryption:

• Protects data but encrypted cardholder data remains in scope
• Organizations must still comply with all PCI DSS requirements for encrypted data
• Requires robust key management and access controls
• Provides protection in transit and at rest
• Best for: Organizations requiring direct access to cardholder data for processing

When to Use Each:

• Use tokenization for systems that don't need real cardholder data (reporting, analytics, customer service)
• Use encryption for payment processing systems requiring actual PAN access
• Combine both approaches for defense-in-depth architecture
• Consider encryption for data in motion and tokenization for data at rest

Compensating Controls Framework

When organizations cannot implement required controls due to legitimate constraints:

When Compensating Controls Are Acceptable:

• Original requirement cannot be met due to legitimate technical or documented business constraints
• Must be documented exception, not convenience
• Requires formal risk acceptance by senior management
• Subject to annual review and reassessment

Requirements for Compensating Controls:

• Must provide equivalent or greater security than original requirement
• Must address both the intent and rigor of original requirement
• Must be above and beyond other PCI DSS requirements
• Cannot simply be existing controls claimed as compensating

Documentation Requirements:

• Constraints preventing compliance with original requirement
• Objective of original requirement being met
• Risk associated with not implementing original requirement
• Compensating controls in place and how they meet objective

Common Acceptable Compensating Control Examples:

• Additional network segmentation when encryption isn't feasible
• Enhanced monitoring and alerting when direct technical control isn't possible
• Increased authentication factors when specific MFA technology unavailable
• Manual procedures with management oversight for automated control gaps

Network Segmentation Validation

Ensuring segmentation effectively reduces scope requires rigorous testing:

Penetration Testing from Outside the CDE:

• Simulate attacks attempting to breach segmentation boundaries
• Test firewall rules, access controls, and network isolation
• Validate that systems outside CDE cannot access cardholder data
• Document findings and remediation actions

Firewall Rule Validation and Testing:

• Review all rules permitting traffic between CDE and other networks
• Remove unnecessary or overly permissive rules
• Test that rules function as documented
• Verify logging captures all boundary traversal attempts

Intrusion Detection/Prevention System Effectiveness:

• Validate IDS/IPS detects boundary violation attempts
• Test alerting mechanisms and response procedures
• Ensure signatures updated regularly
• Verify integration with SIEM for correlation

Annual Re-Validation Requirements:

• Conduct penetration testing at least annually
• Test whenever significant network changes occur
• Document segmentation architecture and validation results
• Update network diagrams to reflect current state

Securing Sensitive Payment Data in Motion

PCI DSS 4.0 extends protection requirements beyond storage and processing to include all transmission channels. Cardholder data moves through email attachments, file shares, managed file transfer systems, web forms, and APIs, each presenting distinct risk profiles and control requirements.

Transport layer encryption protects data in transit but does not prevent unauthorized sharing, excessive permissions, or data exfiltration by compromised credentials. Organizations must layer content-aware controls that inspect payloads, enforce data loss prevention policies, and block transmissions containing unencrypted PANs or sensitive authentication data.

Email remains a common vector for inadvertent cardholder data exposure. Organizations must implement automated scanning that detects payment card patterns, blocks non-compliant transmissions, and quarantines messages for security review. Policies should prohibit email transmission of full PANs and require tokenization or truncation before any payment data leaves secure systems.

File sharing platforms and managed file transfer systems require encryption at rest and in transit, granular access controls, detailed activity logging, and automated expiration of shared links. Organizations must enforce least privilege for file access, implement multifactor authentication for external recipients, and maintain audit trails that document every download and modification.

Zero-trust architecture eliminates implicit trust based on network location and instead validates every access request using identity, device posture, and context. For payment processing systems, zero-trust principles require authentication for every API call, encrypted sessions that terminate at application boundaries, and continuous risk assessment that adapts access policies based on user behavior and threat intelligence.

Content-aware controls inspect data payloads rather than relying solely on metadata or transport encryption. Deep packet inspection, data loss prevention engines, and pattern matching detect PANs, card verification codes, and personal identification numbers regardless of file format or protocol. Organizations must apply these controls at every egress point, including email gateways, web proxies, and file transfer endpoints.

Session-level controls limit the duration, scope, and actions permitted within authenticated connections. Organizations should enforce idle timeouts, restrict clipboard operations, disable screen capture, and log every action taken during privileged sessions. Session recordings provide forensic evidence during incident investigations and satisfy assessor requirements for accountability.

Managing Third-Party Risk and Shared Responsibility

Third-party service providers extend the attack surface and compliance boundary. Payment processors, cloud hosting providers, API vendors, and software-as-a-service platforms require access to cardholder data or systems that affect security posture. Organizations remain accountable for ensuring that third parties implement controls equivalent to internal standards.

Contractual agreements must specify PCI DSS compliance obligations, attestation requirements, incident notification timelines, and audit rights. Organizations should require third parties to provide annual attestations of compliance, maintain liability insurance, and participate in joint incident response exercises.

Continuous monitoring of third-party integrations detects configuration changes, policy violations, and anomalous data flows. Organizations should implement API gateways that log every request and response, enforce rate limits, validate input parameters, and block suspicious patterns. Integration points require the same rigor as internal systems, including encryption, access controls, and audit trails.

Vendor risk assessments transition from annual questionnaires to continuous validation using security ratings services, threat intelligence feeds, and automated scanning of externally facing assets. Organizations should track vendor security posture over time, escalate declining scores, and maintain contingency plans for rapid termination of high-risk relationships.

Cloud-Based Payment Processing Considerations

Cloud-based payment systems must meet the same PCI DSS 4.0 requirements as on-premises systems:

Shared Responsibility Models:

• Clearly define security obligations between cloud provider and customer
• Document which controls provider implements and which customer manages
• Validate that division of responsibility covers all PCI DSS requirements
• Maintain evidence that both parties fulfill their obligations

Cloud Provider Validation:

• Require cloud providers to maintain PCI DSS attestation
• Review provider's AOC (Attestation of Compliance) annually
• Validate that provider's scope includes services you use
• Monitor for changes in provider's compliance status

Data Residency and Access:

• Ensure data residency requirements don't conflict with PCI DSS
• Validate that encryption keys remain under customer control
• Restrict administrative access to authorized personnel
• Monitor cloud configurations for drift from approved baselines

Continuous Configuration Monitoring:

• Implement Cloud Security Posture Management (CSPM) tools
• Detect misconfiguration that could expose cardholder data
• Automate remediation of policy violations
• Integrate cloud audit logs with central SIEM

How the Kiteworks Private Data Network Enables PCI DSS 4.0 Compliance

Compliance frameworks establish baseline security requirements but do not inherently prevent data breaches or operational failures. Organizations must layer active protection controls that enforce policy in real time, prevent unauthorized data flows, and generate evidence without manual intervention. Payment processing systems interact with dozens of downstream applications, reporting tools, and business intelligence platforms. Securing these flows demands a unified layer that enforces consistent controls regardless of protocol, destination, or user role.

The Kiteworks Private Data Network secures sensitive data end to end across email, file sharing, managed file transfer, web forms, and APIs. Organizations use Kiteworks to enforce zero-trust and content-aware controls for cardholder data, generate immutable audit trails that satisfy QSA requirements, and automate evidence collection for continuous compliance validation.

Kiteworks provides encryption for data at rest and in transit using FIPS 140-3 validated cryptographic modules and TLS 1.3 for all data in transit, ensuring payment data protection meets the highest security standards. The platform implements granular access controls that enforce least privilege and detailed activity logs that capture every interaction with payment data.

The platform includes pre-built compliance mappings for PCI DSS 4.0, enabling security teams to demonstrate which controls satisfy specific requirements and accelerate assessor reviews. Organizations deploy Kiteworks as a hardened virtual appliance, on-premises system, or private cloud instance, providing deployment flexibility while maintaining security.

Kiteworks' FedRAMP High-ready status demonstrates government-grade security controls that meet the most stringent operational and compliance requirements, providing assurance to auditors and customers.

Content-aware data loss prevention inspects payloads for payment card patterns, blocks non-compliant transmissions, and quarantines files for security review. Automated workflows enforce session-level controls, expire shared links, and revoke access when employment terminates or roles change. Integration with SIEM platforms delivers real-time alerts for policy violations, configuration drift, and anomalous data flows.

Kiteworks maintains an immutable audit trail that records user identity, file name, timestamp, source address, action taken, and result for every data transfer. These logs support forensic investigations, satisfy incident response requirements, and provide objective evidence during audits. Organizations export audit data to SIEM systems for correlation with network traffic, authentication logs, and threat intelligence.

The platform integrates with identity providers for single sign-on and multifactor authentication, enabling organizations to enforce consistent access policies across all communication channels. Role-based access controls limit data visibility based on user responsibility, department affiliation, and project assignment. Automated access reviews flag dormant accounts, excessive permissions, and policy exceptions.

Maintaining Continuous Compliance and Measuring Outcomes

Achieving initial PCI DSS 4.0 attestation represents a milestone, but organizations must sustain compliance through configuration changes, personnel turnover, technology upgrades, and evolving threats. Continuous compliance requires automation, integration, and governance processes that embed security into operational workflows rather than treating it as an annual event.

Configuration management databases track approved baselines, document change approvals, and trigger scanning when modifications occur. Organizations should implement change control processes that require security review before deploying updates to payment systems, network devices, or access policies. Automated testing validates that changes do not introduce vulnerabilities or violate compliance requirements.

Incident response workflows must address payment data breaches with escalation procedures, forensic preservation, QSA notification, and remediation tracking. Organizations should conduct tabletop exercises that simulate card data exposure scenarios, test communication protocols, and identify gaps in detection or containment capabilities.

Training programs ensure that developers, system administrators, and business users understand their role in protecting cardholder data. Organizations should deliver role-specific training that covers secure coding practices, access management, social engineering awareness, and incident reporting.

Compliance metrics transition from binary pass-fail assessments to continuous measurement of control effectiveness, risk reduction, and operational efficiency. Organizations should track mean time to detect configuration drift, mean time to remediate policy violations, percentage of systems within approved baselines, and audit preparation hours.

Risk registers document identified vulnerabilities, compensating controls, remediation timelines, and accountability. Organizations should prioritize risks based on likelihood and impact, allocate resources to high-priority remediation, and escalate unresolved issues to executive leadership.

Building a Defensible and Sustainable Compliance Posture

PCI DSS 4.0 compliance demands integration between governance, technology, and operations. Organizations that embed compliance into architecture decisions, automate evidence workflows, and enforce zero-trust principles for sensitive data in motion will sustain attestation, reduce audit friction, and minimize breach risk. Achieving PCI DSS 4.0 compliance for payment processing systems requires accurate scoping, continuous monitoring, immutable audit trails, and active protection for cardholder data across all communication channels.

The Kiteworks Private Data Network addresses these requirements by securing sensitive payment data end to end, enforcing content-aware controls that detect and block non-compliant transmissions, maintaining tamper-proof audit trails that satisfy assessor demands, and integrating with SIEM and Security Orchestration, Automation, and Response (SOAR) platforms to deliver automated detection and remediation. Organizations deploy Kiteworks to consolidate fragmented communication channels, reduce third-party risk, and accelerate audit preparation while maintaining operational efficiency and regulatory defensibility.

How can Kiteworks help you?

Schedule a custom demo to see how the Kiteworks Private Data Network helps organizations achieve and maintain PCI DSS 4.0 compliance by securing cardholder data in motion, automating evidence collection, and providing immutable audit trails that satisfy QSA requirements—all while reducing audit preparation time and operational friction.

Key Takeaways

1. Continuous Monitoring Mandate. PCI DSS 4.0 shifts from annual assessments to ongoing validation, requiring organizations to continuously monitor encryption, access controls, and configurations to ensure sustained compliance.
2. Accurate CDE Scoping. Properly mapping the cardholder data environment (CDE) is critical, including all systems and third-party integrations that handle payment data, to avoid audit failures and security gaps.
3. Enhanced Third-Party Accountability. The updated standard emphasizes stricter oversight of third-party providers, mandating contractual compliance validation and continuous monitoring of shared data flows.
4. Securing Data in Motion. Beyond encryption, PCI DSS 4.0 requires content-aware controls and zero-trust principles to protect cardholder data across email, file sharing, and APIs, preventing unauthorized exposure.