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Schellman began as a SOC audit firm 20+ years ago. While we still issue more than 2,000 SOC reports each year, our clients’ trust has propelled our expansion. Today, we offer nearly 60 types of audits and assessments.

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Schellman is the only Top 50 CPA firm focused exclusively on IT Compliance and Cybersecurity, and we’re the #1 service provider for FedRAMP Assessments. Our industry-leading NPS scores, client retention, and employee retention mean our clients experience greater continuity and quality.

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SOC & Attestations

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The Schellman Blog

Stay up to date with the latest compliance news from the Schellman blog.

Mark Stoudemire

Mark Stoudemire is a Senior Associate at Schellman, bringing over 15 years of technical expertise to the firm. Before joining Schellman, he worked as a consultant specializing in IT audit, regulatory compliance, and network security. In his current role, Mark primarily leads PCI-DSS assessments, while also leveraging his broad experience conducting SOC 1 and SOC 2 audits for clients across diverse industries. Mark holds a Master of Science in Cybersecurity and Information Assurance from Western Governors University. He also maintains several respected industry certifications, including CISSP, CISA, and PCI QSA.

Blog Feature

Payment Card Assessments | PCI DSS

PCI DSS v4.x MFA Requirements Explained: Passkeys, Phishing Resistance, and Compliance

By: Mark Stoudemire
October 13th, 2025

As organizations continue to transition to PCI DSS v.4.x, they encounter updated requirements for authentication, especially considering the emerging phishing-resistant technologies like passkeys. To help clarify these changes, the PCI Security Standards Council has released two key FAQs: FAQ 1595 and FAQ 1596, offering valuable insights into the use of passkeys, FIDO2-based authentication, and their alignment with multi-factor authentication (MFA) and phishing-resistant protocols.

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