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BSI C5 Compliance, Audit and Attestation Services

We guide cloud service providers through C5 attestation from gap assessment to final report combining deep cloud security expertise with audit rigour built for the German and DACH market.

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Prove your cloud security to German clients with the standard they actually trust

C5 (Cloud Computing Compliance Criteria Catalogue) is Germany’s government-backed cloud security standard, published by the BSI the Bundesamt für Sicherheit in der Informationstechnik. It combines controls from ISO 27001, ISO 27017, and the Cloud Security Alliance Cloud Control Matrix into a single catalogue built specifically for cloud providers.
Unlike global standards, C5 is cloud-specific and rigorous. German procurement teams ask for it first. Healthcare providers are required to demand it under the DigiG law. Government agencies have mandated it since 2016, and KRITIS critical infrastructure operators must verify it.
C5 attestation proves your infrastructure, operations, and security posture meet German expectations. It’s not a checkbox it’s a market requirement.

Compliance, Without the Compromises

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Direct Line to Your Auditor

No ticket queues. Message your audit team directly and get real answers, fast.

One Team, Every Framework

 
SOC 2, ISO 27001, PCI DSS, pen testing, one team, one timeline, no duplicate evidence.

We Work With Your Stack

We plug into the compliance platforms you already use, adapt to your internal processes, or bring our own tooling if you’d rather not manage one, your call, no extra cost.

Fixed Scope, Fixed Price

 

One clear quote upfront. No change orders, no surprise fees mid-audit.

Timelines You Can Plan Around

Clear milestones from kickoff to report, and we hit them every time.

Always Know Where You Stand

Live visibility into audit progress, no chasing status updates.

Gap Assessment

Built for Fast-Moving Teams

We understand cloud-native, SaaS, and modern DevSecOps, no explaining your stack from scratch.

Support That Doesn't End at the Report

We stay in your corner after the certificate, ongoing guidance, not a one-time transaction.

Our Process.
Simplify the Complex.

01.

Scoping and Gap Assessment

We define your audit scope (services, infrastructure, geography). We map your current controls against C5 requirements. We identify gaps and prioritize remediation. By the end, you know exactly what needs to happen, how long it takes, and what it costs. No surprises.

02.

Remediation and Implementation

You implement missing controls. We guide the process. We deploy technical controls via infrastructure-as-code (faster than manual fixes). We develop policies and procedures. We run training. We also map existing ISO 27001 or SOC 2 evidence to C5 to avoid redundant work.

03.

Evidence Preparation and Testing

You gather evidence. Real logs. Real system configurations. Real training records. We organize it. We map controls to evidence. We validate that controls work before audit. You know weeks in advance whether you’ll pass.

04.

Audit Review

Your team is prepared. All evidence is audit-ready. We conduct a final readiness check with you before the formal C5 audit.

05.

Audit and Attestation

Your BSI-accredited C5 auditor reviews design and operational effectiveness. We help you address any findings. You receive your final C5 attestation report. You’re certified.

06.

Ongoing Support

After attestation, we help you maintain compliance year-round. We track BSI updates. We plan your next audit before the current one expires.

C5 Attestation Benefits

DACH Market Access

Unlock government, healthcare, and regulated buyer contracts across Germany, Austria, and Switzerland.

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Enhanced Client Trust

Demonstrates your commitment 
to data security, strengthening relationships with clients 
and partners.

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Competitive Advantage

Stand out to German procurement teams with cloud security 
credibility that global standards 
don’t provide on their own.

5 4

Reduced Audit Risk

Confirms your environment holds up under scrutiny, lowering the risk of failed audits, breaches, and lost deals.

Schedule a Free Consultation

Pick a time that works for you — no commitment, no sales pressure.

Book a Free 30-Min Call

Why Choose GRSee for C5

White-Glove C5 Service 
We guide you through every step of C5 with hands-on support. A qualified BSI-accredited C5 auditor issues the final attestation report.
We handle the SOC 2 audit procedures with clarity and depth, so you always know what’s happening next.
We simplify every step, removing the stress and confusion from the C5 journey.
Built around your unique cloud infrastructure and market requirements.

We perform C5 audit procedures, coordinate all activities, and keep the process moving. The independent C5 auditor issues the final report.
We provide ongoing guidance to help you maintain and strengthen your compliance posture year-round.
Trusted for high-quality C5 compliance and audit-procedure support across DACH.
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Resources

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 Tom Rozen • Aug 8, 2025

SOC 2 vs. ISO 27001: Comparative Analysis for Informed Decisio...

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SOC 2 Attestation Costs: Understanding the Factors and...

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Tom Rozen• Aug 29, 2025

SOC 2 for Startups: An Essential Guide to Compliance

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Tom Rozen• July 26, 2025

How to Use SOC 3 Compliance to Stand Out in Sales Processes

FAQ

How does C5 attestation differ from ISO 27001?

C5 is cloud-specific and mandatory in Germany. ISO 27001 is a global information security standard. C5 builds on ISO 27001 controls and adds cloud-specific rigor. If you handle German customer data, you need both.

A Type 1 report checks whether your security controls are designed properly at a single point in time. A Type 2 report goes further, it checks whether those controls actually worked consistently over a period of time (usually 3–12 months). Most enterprise customers and procurement teams look for Type 2, since it shows sustained compliance rather than a one-day snapshot..

Yes. Many organizations do. ISO 27001 provides the security foundation. C5 adds privacy and cloud-specific governance. Doing both together is more efficient than sequential certifications.

Type 1: takes a few weeks. Type 2: depending on the observation period. Parallel workstreams cut timelines. Pre-work and readiness assessment pay for themselves in avoiding re-work.

Yes. We can validate control work before the formal audit. We test access controls, encryption, logging, and incident response. You know weeks in advance whether you’ll pass.

There’s no simple pass/fail with C5. An independent auditor from our team tests your controls and issues a report. If gaps are found, the report may come back “qualified,” meaning it discloses the exceptions rather than giving a clean opinion. In practice, most companies catch issues during testing and pause to remediate before a report is ever issued, rather than receiving a qualified one.

Yes. C5, ISO 27001, and SOC 2 are 80% overlapping. We map existing evidence to C5 requirements to avoid redundant work. One control can support multiple standards.

Schedule a Free Consultation

Pick a time that works for you — no commitment, no sales pressure.

Book a Free 30-Min Call

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