Introduction
Every time you tap your card, swipe at a terminal, or complete an online checkout, you make a silent assumption that your payment information will remain safe. Behind that confidence lies a critical defence mechanism that often goes unnoticed: authentication.
Authentication is the digital handshake that verifies you are who you claim to be before granting access to systems or sensitive data. When that handshake is weak or forged, it opens the door to data breaches, fraud, and the erosion of customer trust, outcomes no business can afford in today’s threat landscape.
In August 2025, the Payment Card Industry Security Standards Council (PCI SSC) published an updated Authentication Guidance, a document that has quickly become a focal point across the payment security community. As we move through November, the industry is still unpacking its depth, implications, and actionable insights.
This guidance doesn’t just reinforce compliance expectations, like enforcing multi-factor authentication (MFA) for all access to cardholder data, mandating unique identities for every user, and hardening password and credential reset processes; it reimagines how organizations can raise the bar for authentication in a world of advanced threats and evolving fraud tactics.
The Foundations Of Strong Authentication
At its foundation, authentication serves as the gatekeeper of trust within any payment ecosystem. It ensures that only verified and authorized individuals can gain access to systems, networks, and cardholder data, protecting the integrity of transactions and maintaining customer confidence.
Authentication is not solely a technical control; it is equally maintained through disciplined access policies, governance practices, and procedural safeguards that enforce how credentials are issued, managed, and revoked. Together, technology and strong procedural frameworks create a comprehensive defence that withstands both technical exploits and operational weaknesses.
According to the PCI SSC, strong authentication goes beyond simply checking a username and password. It must provide assurance that access is granted only to legitimate users and that those users are validated through secure, multi-layered mechanisms. In practice, this means:
- Restricting access exclusively to authorized personnel who have a verified business need to interact with cardholder data or payment systems.
- Employing authentication methods stronger than traditional passwords, such as token-based authentication using hardware or software tokens, certificate-based access controls, or biometric verification, is especially critical in sensitive environments where payment data is processed, stored, or transmitted. These methods provide enhanced security by requiring additional proof of identity beyond a simple password, significantly reducing the risk of unauthorized access.
- Integrating multiple factors of authentication, combining something the user knows (like a password), something they have (like a token or device), and something they are (like a fingerprint or facial ID), to dramatically reduce the risk of compromise. These are also the 3 main types of authentications defined by PCI.
- Ensuring continuous validation, meaning authentication doesn’t stop at login; session controls, device verification, and behavioural analysis should all play a role in maintaining trust throughout a user’s access.
In short, PCI SSC emphasizes that strong authentication isn’t just about who gets in; it’s about ensuring that only the right people, with the right credentials, and through the right mechanisms, can ever touch sensitive payment data.
Key Best Practices From PCI
While PCI DSS defines the baseline requirements, the Authentication Guidance document pushes organizations to think beyond compliance and toward long-term cyber resilience. It reflects a world where attackers are not just guessing passwords but leveraging AI, deepfakes, and social engineering to bypass outdated defences. Below are best practices that, while not required, should be considered when implementing an authentication system.
- Educate users on how to generate secure passwords.
- Implement controls to mitigate deepfake attacks.
- Provide suitable time limits for OTP use. Allow users to paste data into password and OTP fields.
- Store authentication secrets securely with methods such as memory-hard comparison functions with unique-per-password salts or attack-resistant storage such as Hardware Security Modules (HSMs) or Hardware Management Devices (HMDs).
- Implement online and offline brute-force protections for credentials.
- Secure systems that can be used to gain access to authentication factors by implementing SIM PINs, lockscreen controls, notification blocking, account porting controls, etc.
- Consider the use of more secure authentication factors instead of messaging-based factors.
- Consider all locations where a credential exists or may be compromised to be in scope for applicable security controls.
- Implement phishing-resistant authentication wherever possible.
- Implement device-bound factors (such as device-bound passkeys, smartcards, tokens, etc.) for sensitive access operations (such as administrative access or access for high-security areas and tasks).
- Limit the business use of synced passkeys to minimize the scope of applicable security requirements.
- Implement multi-factor authentication wherever possible.
- Secure the (re)enrollment process to prevent account takeover attacks.
- Bind session credentials to specific devices or users wherever possible.
- Validate all MFA factors, or non-static factors, before indicating success/failure.
- Include authentication methods when considering acceptable cryptographic minimums and crypto agility.
Why These Practices Matter
The August 2025 guidance marks one of PCI SSC’s most forward-looking publications to date. It underscores a truth the security community has long recognized: strong authentication is not a box to check; it’s a cornerstone of trust. These practices matter because:
- Threat sophistication is accelerating rapidly: Attackers now use tools like AI-generated phishing, deepfake impersonation, and automated credential-based attacks that easily defeat outdated authentication methods.
- Authentication factors themselves are now high-value targets: PCI’s guidance helps organizations secure the systems, devices, and channels that store or deliver authentication factors, reducing the likelihood that attackers can intercept or manipulate them.
- Account lifecycle processes are becoming a major vulnerability: Weak enrolment and recovery procedures are a common path for account takeover. Strengthening these processes ensures that identity cannot be hijacked through procedural loopholes.
- Device trust is increasingly essential: As more business operations rely on personal or unmanaged devices, binding authentication and session credentials to verified devices prevents unauthorized access through compromised endpoints.
- Cloud expansion has reshaped the security perimeter: With authentication now acting as the “new perimeter,” PCI’s recommendations help organizations maintain consistent identity assurance across hybrid, multi-cloud, and remote-access environments.
- Payment ecosystems must demonstrate higher assurance to customers and partners: Modern authentication practices support stronger security assurances, which directly influence customer confidence, partner reliability, and auditor expectations.
- Future cryptographic changes demand long-term planning: PCI’s emphasis on crypto-agility ensures organizations are prepared for emerging cryptographic transitions, including quantum-safe requirements, before these changes impact authentication security.
Maturity Model For Strong Authentication
To build a scalable and future-ready authentication strategy aligned with PCI’s latest guidance, organizations can adopt a maturity model with clearly defined progression stages:
Level 1: Basic Credentials with Targeted Password Policies
- Authentication relies primarily on usernames and passwords.
- Password policies enforce complexity and periodic changes. Importantly, PCI DSS requires 90-day password rotations only for accounts using single-factor authentication; accounts with MFA are exempt from this rotation mandate.
- This level addresses basic access control but remains vulnerable to phishing and credential theft.
Level 2: Mandatory Multi-Factor Authentication for All Cardholder Data Environment (CDE) Access
- MFA implementations must combine independent authentication factors (knowledge, possession, and inherence) to ensure that compromising one factor does not weaken overall security.
- This stage significantly reduces the risk of unauthorized access through credential compromise and aligns with PCI’s strict authentication requirements.
- PCI DSS 4.0 mandates MFA for all access to the CDE, not limited to privileged or remote users.
Level 3: Risk-Adaptive and Context-Aware Authentication Controls
- Authentication dynamically adjusts based on risk signals like user behaviour, device trust levels, geolocation, and threat intelligence.
- Continuous session monitoring and binding session credentials to specific trusted devices enhance detection and prevention of abnormal access or lateral movements.
- This level integrates adaptive security techniques to respond swiftly to emerging threats.
Level 4: Phishing-Resistant, Hardware-Anchored, and Crypto-Agile Identity Systems
- Employs advanced phishing-resistant authentication technologies, such as FIDO2 hardware security keys, certificate-based smart cards, and biometric devices.
- Authentication factors are hardware-anchored using asymmetric cryptography to eliminate risks from replay or man-in-the-middle attacks.
- Integrates crypto-agility principles, preparing for migration to quantum-safe algorithms, with the target quantum-safe compliance timeline aligned with global guidance.
- This highest maturity level optimizes both security and usability, representing future-proof identity systems for critical payment environments.
How Encryption Consulting Helps You Achieve PCI DSS Compliance
Achieving PCI DSS compliance requires proactive protection of sensitive cardholder data. Encryption Consulting offers tailored advisory services to help your business meet these requirements efficiently and securely.
1. Tailored Encryption Strategy: We design encryption solutions aligned with PCI DSS standards, such as AES-256, to protect data-at-rest, in-transit, and in-use. Our customized approach ensures seamless integration into your existing systems with minimal disruption.
2. Encryption Assessments: Through detailed assessments based on NIST and FIPS 140-2, we identify weaknesses like outdated protocols, weak key management, or misconfigured SSL/TLS settings. Addressing these issues strengthens your encryption architecture and supports ongoing compliance.
3. Governance & Key Management: We help you build a robust key management framework that includes secure storage, rotation, and deactivation practices. Using tools like CertSecure Manager, we automate key lifecycles, improve visibility, and enable MFA for enhanced security and compliance.
4. Continuous Compliance & Risk Mitigation: Our services extend beyond initial compliance, providing regular audits, monitoring, and training to maintain alignment with PCI DSS updates. We also empower your team to manage HSMs and PKI systems confidently.
Conclusion
The PCI Authentication Guidance is a call to action, and it is shaping how organizations rethink authentication in a world of emerging threats and digital transformation. The message is simple and urgent: implement multi-factor authentication wherever possible, secure credentials at every stage, and continuously evolve your defences.
By embracing PCI’s latest recommendations and leveraging the expertise of Encryption Consulting, organizations can go beyond compliance to build a truly secure, trusted payment environment that protects both their customers and their reputations.
