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Data Protection and AI in Swiss Law Firms: nDSG Compliance in Practice

The revised Data Protection Act (nDSG) poses new challenges for law firms using AI tools. What requirements apply? What can go to the cloud? A practical guide.

Orlando Kahanek · · Updated:

Since September 1, 2023, the revised Swiss Data Protection Act (nDSG, SR 235.1) has been in force. For law firms wanting to use AI tools, the central question is: How can the use of Legal AI be reconciled with data protection and attorney-client privilege?

This question is not academic – it has concrete professional law consequences. Art. 13 BGFA (Federal Act on the Free Movement of Lawyers) obliges attorneys to maintain professional secrecy. A violation can lead to revocation of the law license.

Key nDSG Requirements for AI Use

1. Privacy by Design and Data Protection Impact Assessment

Art. 7 nDSG requires «Privacy by Design» – data protection must be considered from the design stage. For AI tools, this means:

  • Data may only be stored as long as necessary for the purpose
  • Technical measures must restrict access to what is necessary
  • Default settings must be privacy-friendly

Art. 22 nDSG requires a Data Protection Impact Assessment (DPIA) when data processing may pose a high risk. Using AI to analyze client data typically requires a DPIA.

2. Disclosure Abroad

Art. 16-17 nDSG regulate data transfer abroad. Personal data may only be transferred to states ensuring adequate data protection. The Federal Council maintains a corresponding country list.

Practical relevance: Using an AI tool that processes data on US servers (ChatGPT, Claude, Gemini) constitutes disclosure abroad. The USA has been on the adequacy list since the Swiss-U.S. Data Privacy Framework (DPF), but only for DPF-certified companies. Verify whether your AI provider is DPF-certified. If not, additional safeguards are required – additional safeguards are required.

3. Attorney-Client Privilege and AI

Attorney-client privilege (Art. 321 SCC) protects all information entrusted to the attorney in their professional capacity. Disclosure to third parties is generally punishable – including to a cloud provider.

The Swiss Bar Association (SAV) stated in its guideline «Cloud Computing and Attorney-Client Privilege» (2022):

The use of cloud services is compatible with attorney-client privilege, provided technical and contractual measures ensure confidentiality.

Specifically:

  • Encryption: Data must be encrypted in transit and at rest (minimum AES-256)
  • Access control: The cloud provider must not have access to plaintext
  • Server location: Preferably Switzerland, at minimum EU/EEA with adequate data protection
  • No model training: Client data must never be used for AI model training

Verification Schema for Law Firms

  1. Where is data processed? (server location)
  2. Is data used for model training? (exclusion criterion if yes)
  3. What encryption is used? (minimum: AES-256, TLS 1.3)
  4. Is there a data processing agreement? (Art. 9 nDSG)
  5. Is a DPIA required? (Art. 22 nDSG – for client data: yes)
  6. Is the provider on the FDPIC supervision list?

Concrete Risk Scenarios

Scenario 1: Entering Client Data in ChatGPT

Risk: HIGH

  • Data processed on US servers
  • OpenAI may use inputs for model training (unless disabled in Enterprise version)
  • No data processing agreement in Free/Plus version
  • Potential violation of Art. 321 SCC (professional secrecy)

Scenario 2: Document Analysis with Swiss-Hosted Legal AI

Risk: LOW (with correct implementation)

  • Data remains in Switzerland (storage with Safe Swiss Cloud, AI processing via Azure Switzerland North)
  • No model training with customer data
  • Data processing agreement in place
  • AES-256 encryption
  • Automatic deletion after analysis

Scenario 3: E-Mail-Assistanten mit KI

Risk: MEDIUM

  • Dependent on provider and their data policies
  • E-mail content may contain client data
  • Microsoft 365 Copilot: Data stays in tenant, no model training (but US processing possible)

Checklist: nDSG-compliant use of AI in the law firm

  • [ ] Data protection impact assessment (DPIA) carried out for every AI use involving personal data
  • [ ] Data processing agreement concluded with the AI provider
  • [ ] Server location in Switzerland (or an adequate level of data protection)
  • [ ] Encryption: AES-256 at rest, TLS 1.3 in transit
  • [ ] No model training with law firm data confirmed
  • [ ] Duty to inform clients fulfilled (Art. 19 nDSG)
  • [ ] Record of processing activities updated (Art. 12 nDSG)
  • [ ] Deletion concept defined and implemented
  • [ ] Staff trained on AI and data protection

Conclusion: AI yes – but with the right guardrails

Using AI in Swiss law firms is compatible with the nDSG and professional secrecy – provided the right technical and organisational measures are in place. The key factors:

  1. Data location in Switzerland is the safest route
  2. No model training with client data is non-negotiable
  3. A DPIA is mandatory for AI use involving personal data
  4. The data processing agreement must address the AI-specific risks

Law firms that respect these guardrails can use AI tools with legal certainty and increase their efficiency – without jeopardising their clients' trust.

RechtsKI processes all data exclusively in Switzerland: storage is with Safe Swiss Cloud, and AI processing runs by default via Microsoft Azure (Switzerland North) or, per request, entirely via Safe Swiss Cloud. No model training is performed with customer data. The platform is nDSG-compliant and uses AES-256 encryption.

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