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Export Security

CalcBridge implements multiple security layers to protect exported data.

Zip Bomb Protection

Before processing any XLSX file (import or export verification), CalcBridge validates the archive:

Check Default Limit
Maximum compression ratio 100:1
Maximum file count 5,000 files
Maximum uncompressed size Configurable per deployment (default 250 MB)

Files exceeding these limits are rejected with a ZipBombError.

Verify Endpoint Hardening

The public verification endpoint is protected with layered controls:

  • Rate limits: 10 requests/min unauthenticated, 100 requests/min authenticated
  • Upload size: 25 MB public, 100 MB authenticated
  • Decompressed size cap: enforced before reading worksheets
  • Sandboxed execution: CPU and memory limits during hash computation
  • Antivirus scan: rejects infected uploads
  • Temporary retention: verify uploads are purged automatically

PII Redaction

Exports can optionally redact personally identifiable information:

  • Enable with redact_pii: true in export options
  • Applies configurable redaction rules before export
  • Redacted fields are replaced with masked values

Password Protection

XLSX and PDF exports support password encryption:

  • Set via password option in export request
  • XLSX uses standard Office encryption
  • PDF uses PDF encryption standards

File Expiration

Export files automatically expire after a configurable period:

  • Default: 24 hours
  • Expired exports return 410 Gone on download attempts
  • Files are cleaned up by a background task

Access Control

  • Exports inherit workbook-level permissions
  • Only users with read access to the source workbook can create exports
  • Download links are tenant-isolated via Row-Level Security
  • Cross-tenant access attempts return 403 Forbidden