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File Secret Details

This page provides detailed information about file secrets, including supported types, size limits, and security considerations.

Supported File Types

Cellar accepts all file types without restrictions. You can upload:

  • QR codes and barcodes
  • Screenshots and images
  • PDF documents
  • Private keys and certificates
  • Configuration files
  • Source code archives
  • Short audio recordings
  • Any other file type

Recipients are responsible for safely handling downloaded files. Cellar focuses on secure transmission and storage, not content filtering.

File Size Limits

The default maximum file size is 8 MB. This limit supports common use cases while remaining compatible with AWS Lambda deployments.

Files that fit within 8 MB:

  • QR codes (< 1 MB)
  • Screenshots (2-5 MB)
  • PDFs with text and images (1-6 MB)
  • Private keys and certificates (< 1 MB)
  • Configuration files (1-5 MB)
  • Short audio clips (1-2 MB)

If you need to upload larger files, contact your Cellar administrator. Docker and traditional server deployments can increase this limit through configuration. See the deployment documentation for configuration details.

Security Considerations

File uploads implement several security measures:

Automatic Protections:

  • Empty files (0 bytes) are rejected
  • File size is validated before encryption
  • Secure download headers prevent XSS attacks
  • Filenames are sanitized to prevent path traversal

Best Practices:

  • Set appropriate expiration times based on file sensitivity
  • Use access limits to prevent unauthorized sharing
  • Share secret links through secure channels (not email)
  • Recipients should verify downloaded files before opening

Privacy Note: File metadata (filename, size, type) is intentionally not displayed on the Secret Metadata page. This prevents information leakage about the secret’s content. Only the recipient accessing the secret will see the file information.

Limitations

File uploads have the following limitations:

  • Maximum file size: 8 MB (default, configurable by administrators)
  • Files are stored in memory during encryption
  • Files are stored in the datastore after encryption
  • No virus scanning or content filtering is performed

For large files or different requirements, consider alternative file sharing solutions.

API Support

File secrets use the v2 API endpoints with multipart/form-data encoding.

Minimum versions:

  • Cellar API: v3.2.0+
  • Cellar UI: v3.0.0+

For direct API usage or integration, refer to the API documentation.