Why Reversible Encryption?
Sometimes you need to protect data temporarily, not destroy it forever
Temporary Protection
Share documents with external parties during a project, then restore original data when the project ends.
Audit Compliance
Anonymize production data for testing but maintain ability to trace back to originals for audit purposes.
Legal Discovery
Protect sensitive information during legal proceedings while preserving the ability to restore if required by court order.
Safe AI Workflows
Send anonymized prompts to AI assistants, then restore context when reviewing outputs internally.
How It Works
1. Create Your Key
You create your own encryption key — a password of exactly 16, 24, or 32 characters. This key is never sent to or stored on our servers. You are the only one who knows it.
2. Encrypt & Share
Select the Encrypt method during anonymization. Each detected PII value becomes an encrypted token like <encrypted:xyz123>. Share freely — without your key, the data is unrecoverable.
3. Decrypt with Same Key
Open the Deanonymizer, paste encrypted text, enter the exact same key you used to encrypt, and click Decrypt. Original values are restored instantly.
Your Keys, Your Control
You create and safeguard your encryption keys. We never store them.
You Create the Key
Choose a strong password of 16, 24, or 32 characters. This becomes your AES encryption key. We do not generate keys for you.
Key Never Stored
Your key is transmitted securely over HTTPS for encryption, then immediately discarded. We never store your key on our servers.
Same Key Required to Decrypt
Decryption requires the exact key used during encryption. Even one wrong character means decryption fails.
No Recovery If Lost
We cannot recover your data if you lose your key. Store it securely in a password manager. This is by design.
Anonymization Methods Compared
Encrypt is the only method that allows original data recovery with your key
| Method | Reversible | Readable | Linkable | Best For |
|---|---|---|---|---|
| encrypt | Temporary workflows, audits, legal | |||
| replace | Testing, demos, training data | |||
| redact | Legal documents, public records | |||
| hash | Research, analytics, pseudonymization | |||
| mask | Support, UI display |
Replace, Redact, Hash, and Mask permanently destroy original data. Only Encrypt preserves recoverability — but requires you to securely store the key you created.
Real-World Use Cases
AI Assistant Workflows
Anonymize sensitive customer data before sending to ChatGPT, Claude, or other AI assistants. Use the Chrome Extension or MCP Server to encrypt on-the-fly, then restore context when reviewing AI outputs internally.
"Customer John Smith (john@company.com) reported..." → "Customer <encrypted:xyz> (<encrypted:abc>) reported..." → Original restored after AI processing
Vendor Data Sharing
Share project documents with external consultants or vendors without exposing real names, emails, or other PII. When the engagement ends, restore originals for internal records.
Share anonymized contracts during due diligence, restore originals for final signing
Production-to-Test Data
Copy production databases to test environments with encrypted PII. Developers work with realistic data structures while actual values remain protected. Restore for debugging specific issues.
Test with encrypted user data, decrypt specific records when investigating bugs
Legal Hold & Discovery
During litigation, anonymize documents shared with opposing counsel. If court orders restoration, you retain the ability to decrypt without having destroyed evidence.
Protect witness identities during discovery, restore if subpoenaed
Technical Specifications
Military-grade encryption for enterprise trust
AES-256-GCM
Advanced Encryption Standard with 256-bit keys and Galois/Counter Mode for authenticated encryption. Used by banks, governments, and military worldwide.
Key Requirements
16, 24, or 32 character keys (128, 192, or 256 bits). Longer keys provide stronger security.
Token Format
Encrypted values are stored as <encrypted:base64data> tokens, allowing easy identification and decryption.
Zero Key Storage
Your encryption key is never stored on our servers. If you lose your key, encrypted data cannot be recovered — by design.
Available Everywhere
Use reversible encryption across all cloak.business platforms
Web Application
Full encrypt/decrypt workflow in the Anonymizer and Deanonymizer tabs
REST API
POST /api/presidio/anonymize with encrypt operator, POST /api/presidio/deanonymize to restore
MCP Server
text_anonymize and text_detokenize tools for Claude Desktop and compatible AI assistants
Desktop App
Document processing with encrypt method, key management synced with your vault
Chrome Extension
One-click encryption for ChatGPT, Claude.ai, and Gemini conversations
Security Guarantees
- Your encryption key is transmitted securely over HTTPS and never stored on our servers
- Encrypted tokens are computationally infeasible to decrypt without the correct key
- We never store your encryption key — if you lose it, we cannot help you recover data
- All processing happens on ISO 27001-certified servers in Nuremberg, Germany
- AES-256-GCM provides both confidentiality and integrity verification
Frequently Asked Questions
What happens if I lose my encryption key?
Encrypted data becomes permanently unrecoverable. We do not store your key and have no way to decrypt your data. Always store your encryption key in a secure password manager.
Can I use different keys for different documents?
Yes. Each anonymization operation uses the key you provide. You can use different keys for different projects, but you must track which key was used for which document.
What are the key requirements?
Keys must be exactly 16, 24, or 32 characters (128, 192, or 256 bits). Longer keys provide stronger encryption. We recommend 32-character keys for maximum security.
Can I decrypt only some values?
Currently, decryption processes all encrypted tokens in the text. You cannot selectively decrypt individual values while leaving others encrypted.
Can I decrypt via API?
Yes. Use POST /api/presidio/deanonymize with the encrypted text and your key. The API returns the fully restored original text.
Related Features
Explore other capabilities that work seamlessly with reversible encryption
All Anonymization Methods
Compare all 5 anonymization methods: Replace, Redact, Hash, Encrypt, and Mask. Choose the right one for your use case.
Zero-Knowledge Security
Your password never leaves your device. Same security principles that protect your encryption keys.
MCP Server Integration
Use reversible encryption directly in Claude Desktop, Cursor, and VS Code with our MCP server.