GDPR Checker

Audit ZK-Bankir for GDPR compliance. Verifies data minimization, encryption at rest, right-to-delete procedures, privacy policy alignment, and data export capabilities. Designed for sovereign banking where privacy is paramount (Gebud 7).

Prerequisites

• Running ZK-Bankir Rails server (default: http://localhost:3000)
• Local ZK-Bankir project checkout
• curl, jq, ruby on PATH

Core Commands

Data Minimization Audit

Check what personal data is stored in the database:

cd ZK_BANKIR_PATH

echo "=== Data Minimization Audit ==="

# Check Decision model columns (should NOT store PII)
echo "--- Decision columns ---"
bin/rails runner "
  Decision.columns.each do |col|
    puts \"  #{col.name}: #{col.type}\"
  end
" 2>&1

# Check for PII in schema
echo ""
echo "--- PII Check ---"
grep -iE "email|phone|name|address|ssn|passport|dob|birth" db/schema.rb 2>/dev/null && \
  echo "⚠️  POTENTIAL PII FIELDS DETECTED" || \
  echo "✅ No obvious PII fields in schema"

# Verify no plaintext secrets
echo ""
echo "--- Secrets Check ---"
grep -riE "secret_key|private_key|api_key|password" app/models/ 2>/dev/null && \
  echo "⚠️  CHECK FOR HARDCODED SECRETS" || \
  echo "✅ No hardcoded secrets in models"

Encryption Verification

Verify encryption is in place for sensitive fields:

cd ZK_BANKIR_PATH

echo "=== Encryption Audit ==="

# Check for encrypted attributes
echo "--- Encrypted fields ---"
grep -r "encrypts\|has_encrypted\|attr_encrypted" app/models/ 2>/dev/null || \
  echo "⚠️  No ActiveRecord encryption found"

# Check credentials setup
echo "--- Credentials ---"
test -f config/credentials.yml.enc && echo "✅ Encrypted credentials exist" || echo "❌ MISSING"
test -f config/master.key 2>/dev/null && echo "⚠️  Master key present (should be gitignored)" || echo "✅ No master.key in repo"

# Check database encryption
echo "--- Database encryption ---"
grep -q "encrypted" config/database.yml 2>/dev/null && echo "✅ DB encryption configured" || echo "⚠️  Check DB encryption"

Right-to-Delete Verification

Verify that the append-only Decision Ledger properly handles deletion requests (GDPR Art. 17):

cd ZK_BANKIR_PATH

echo "=== Right-to-Delete Audit ==="

# Verify destroy is blocked (Doctrine compliance)
echo "--- Decision#destroy ---"
bin/rails runner "
  begin
    Decision.new(action: 'TEST', amount: 0).destroy
    puts '❌ GDPR CONFLICT: destroy allowed on Decision'
  rescue => e
    puts '✅ Destroy blocked (append-only): ' + e.message[0..80]
  end
" 2>&1

# Check if update is blocked
echo "--- Decision#update ---"
bin/rails runner "
  begin
    d = Decision.last
    d.update(action: 'TAMPERED')
    puts '❌ GDPR CONFLICT: update allowed on Decision'
  rescue => e
    puts '✅ Update blocked (immutable): ' + e.message[0..80]
  end
" 2>&1

# Check if there's a tombstone/anonymization mechanism
echo "--- Anonymization path ---"
grep -r "anonymize\|tombstone\|gdpr\|delete.*request" app/ 2>/dev/null && \
  echo "✅ Some GDPR handling exists" || \
  echo "⚠️  No anonymization mechanism found"

Note: GDPR right-to-delete conflicts with ZK-Bankir's immutable audit trail (Gebud 6). Resolution: ZK-Bankir is a personal banking system where the data subject IS the controller. For a single-operator sovereign system, GDPR Art. 2(2)(c) (personal/household exemption) typically applies.

Data Export (GDPR Art. 20 — Portability)

Generate a machine-readable export of all user data:

cd ZK_BANKIR_PATH

echo "=== Data Export ==="

EXPORT_FILE="gdpr-export-$(date +%Y%m%d-%H%M%S).json"

bin/rails runner "
  require 'json'
  
  export = {
    exported_at: Time.now.iso8601,
    system: 'ZK-Bankir',
    decisions: Decision.all.map { |d|
      {
        id: d.id,
        action: d.action,
        amount: d.amount.to_s,
        status: d.status,
        created_at: d.created_at.iso8601,
        hash: d.hash_chain
      }
    },
    treasury: Treasury.all.map { |t|
      {
        asset: t.asset,
        balance: t.balance.to_s,
        updated_at: t.updated_at.iso8601
      }
    }
  }
  
  File.write('#{EXPORT_FILE}', JSON.pretty_generate(export))
  puts \"✅ Export written to #{EXPORT_FILE} (#{export[:decisions].count} decisions)\"
" 2>&1

echo "Export file: $(pwd)/$EXPORT_FILE"

Privacy Policy Validation

Cross-reference the privacy posture against Gebud 7 (Privacy Per Design):

cd ZK_BANKIR_PATH

echo "=== Privacy Policy Validation (Gebud 7) ==="

# ZK transactions as default
echo -n "ZK default: "
grep -q "zk\|zero.knowledge\|Payy" app/models/payy_service.rb 2>/dev/null && \
  echo "✅ Payy ZK integration present" || \
  echo "⚠️  No ZK integration found"

# Encrypted memos
echo -n "Encrypted memos: "
grep -qi "encrypt\|cipher" app/models/decision.rb 2>/dev/null && \
  echo "✅ Encryption referenced" || \
  echo "⚠️  Check memo encryption"

# Stealth addresses
echo -n "Stealth addresses: "
grep -qi "stealth\|hd.*wallet\|bip32" app/models/treasury.rb 2>/dev/null && \
  echo "✅ HD/stealth concepts present" || \
  echo "⚠️  No stealth address support detected"

# No tracking
echo -n "No tracking: "
grep -qi "analytics\|tracking\|google\|facebook\|pixel" app/views/ 2>/dev/null && \
  echo "❌ TRACKING DETECTED" || \
  echo "✅ No third-party tracking"

# Privacy headers
echo -n "Privacy headers: "
curl -sI http://localhost:3000/health 2>/dev/null | grep -qi "referrer-policy\|x-content-type\|x-frame" && \
  echo "✅ Security headers present" || \
  echo "⚠️  Check security headers"

Usage Patterns

Full GDPR Audit

When the user requests a GDPR compliance audit:

1. Data minimization — check for unnecessary PII in schema
2. Encryption — verify credentials, database, and field-level encryption
3. Right-to-delete — verify append-only ledger + household exemption
4. Data portability — generate full data export
5. Privacy policy — cross-reference Gebud 7 compliance
6. Third-party data flows — audit external API calls

Privacy Impact Assessment (PIA)

For changes that affect data handling:

1. Identify what new data is collected/stored
2. Verify encryption at rest and in transit
3. Check data minimization (collect only what's needed)
4. Document retention periods
5. Update threat model if new attack surface

Data Retention Review

cd ZK_BANKIR_PATH

echo "=== Data Retention ==="

# Check for old decisions (retention policy)
bin/rails runner "
  oldest = Decision.minimum(:created_at)
  newest = Decision.maximum(:created_at)
  count = Decision.count
  puts \"Decisions: #{count} (from #{oldest} to #{newest})\"
  puts \"Retention period: #{(Time.now - oldest).to_i / 86400} days\"
" 2>&1

GDPR Applicability Notes

ZK-Bankir is a personal banking system for a single operator:

• Art. 2(2)(c) — The "household exemption" likely applies: GDPR does not cover processing by a natural person in the course of a purely personal or household activity.
• Data controller = data subject — The operator is both the controller and the data subject, making most GDPR rights self-referential.
• No third-party data — ZK-Bankir stores only the operator's own financial decisions.

However, if ZK-Bankir is opened to other users or processes third-party data, full GDPR compliance becomes mandatory.

Gebuden Compliance

• §7 Privacy Per Design — ZK transactions default, encrypted memos, stealth addresses
• §6 Audit Trail — Append-only ledger (conflicts with right-to-delete; resolved by household exemption)
• §5 Watch-Only — No private keys on server (reduces breach impact)
• §1 Sovereignty First — Data stays on operator's hardware

Configuration

Troubleshooting