SOC 2 (System and Organization Controls 2) is an auditing framework developed by the AICPA (American Institute of Certified Public Accountants). It is not government legislation or a certification scheme but a voluntary attestation standard — however, it has become a de facto market requirement for any technology company, cloud service provider, or SaaS vendor serving enterprise customers, particularly in the US. A SOC 2 report is produced by an independent CPA firm that evaluates an organization’s controls against the AICPA’s Trust Services Criteria (TSC), organized in five categories: Security (mandatory for all SOC 2 reports, covering Common Criteria CC1–CC9), Availability, Processing Integrity, Confidentiality, and Privacy (each optional depending on the organization’s services and customer commitments). The Common Criteria (CC1–CC9) are derived from the COSO Internal Control Framework and cover control environment, risk assessment, monitoring, logical/physical access, system operations, change management, and risk mitigation. There are two report types: Type I (evaluates control design at a point in time) and Type II (evaluates both design and operating effectiveness over 6–12 months — the standard enterprise customers demand). SOC 2 reports are restricted-use documents shared with customers under NDA. While not legally mandatory, major enterprises, financial institutions, and regulated industries routinely require SOC 2 Type II reports from their vendors before signing contracts, making it an essential market-access requirement for technology service providers.
The BSI C5 (Cloud Computing Compliance Criteria Catalogue) is a German federal standard published by the BSI that defines minimum security requirements for cloud service providers. First released in 2016, the catalogue has undergone two major revisions: C5:2020 and the current C5:2026 (published 7 April 2026, replacing C5:2020). C5:2026 contains 168 criteria (up from 121 in C5:2020, a 39 % increase) structured across 17 domains aligned with ISO/IEC 27001 Annex A. The new version introduces a sub-criteria structure aligned with the European EUCS scheme, and adds five major new requirement areas: Confidential Computing (OPS-32/33: documented policies for Trusted Execution Environments and technical implementation of Remote Attestation), Container Management (OPS-34/35: lifecycle security for containerized workloads), Post-Quantum Cryptography (inventory of cryptographic assets and migration plan to quantum-resistant algorithms), AI transparency (disclosure of AI use in internal control systems), and Supply Chain Security (SBOM requirements, documented sub-processor audits). The catalogue is published in machine-readable YAML format for the first time. C5 is designed as an attestation standard (not a certification): providers undergo a Type 2 audit by an independent auditing firm (under IDW PS 880 or ISAE 3000), which verifies both the design and operational effectiveness of security controls over a period of at least six months. C5 is now effectively mandatory in two key domains: since 1 July 2025, cloud providers processing healthcare data must hold a valid C5 Type 2 attestation under §393 SGB V (Social Code, Fifth Book), and the revised BSI-KritisV (2024) requires KRITIS operators to use C5-attested cloud services in security-relevant contexts. Public-sector procurement in Germany also increasingly demands C5 attestation. C5:2026 becomes mandatory on 1 June 2027 for all audit periods starting on or after that date. During the transition: C5:2020 audits remain valid without additional requirements until 28 February 2027; between 28 February and 31 May 2027, C5:2020 is still permitted but requires a transition roadmap to C5:2026 in the system description.
