Secure anonymization/de-anonymization library for PII data
npm install @anonymask/core> Secure anonymization/de-anonymization library for protecting Personally Identifiable Information (PII) in Node.js applications. Built with Rust for maximum performance.
- 🚀 Blazing Fast: Rust-powered core with < 5ms processing time
- 🔍 Comprehensive Detection: EMAIL, PHONE, SSN, CREDIT_CARD, IP_ADDRESS, URL
- 🔒 Secure Placeholders: Deterministic UUID-based anonymization
- 🛡️ Type-Safe: Full TypeScript support with detailed definitions
- ⚡ Zero Dependencies: No external runtime dependencies
- 🧵 Thread-Safe: Safe for concurrent use
``bash`
npm install @anonymask/core
`javascript
const { Anonymizer } = require("@anonymask/core");
// Initialize with desired entity types
const anonymizer = new Anonymizer(["email", "phone", "ssn"]);
// Anonymize text
const text = "Contact john@email.com or call 555-123-4567. SSN: 123-45-6789";
const result = anonymizer.anonymize(text);
console.log(result.anonymizedText);
// "Contact EMAIL_xxx or call PHONE_xxx. SSN: SSN_xxx"
console.log(result.mapping);
// { EMAIL_xxx: 'john@email.com', PHONE_xxx: '555-123-4567', SSN_xxx: '123-45-6789' }
console.log(result.entities);
// [
// { entity_type: 'email', value: 'john@email.com', start: 8, end: 22 },
// { entity_type: 'phone', value: '555-123-4567', start: 31, end: 43 },
// { entity_type: 'ssn', value: '123-45-6789', start: 50, end: 60 }
// ]
// Deanonymize back to original
const original = anonymizer.deanonymize(result.anonymized_text, result.mapping);
console.log(original);
// "Contact john@email.com or call 555-123-4567. SSN: 123-45-6789"
`
| Type | Description | Examples |
| ------------- | ----------------------- | --------------------------------------------------- |
| email | Email addresses | user@domain.com, john.doe@company.co.uk |phone
| | Phone numbers | 555-123-4567, 555-123, (555) 123-4567, 555.123.4567 |ssn
| | Social Security Numbers | 123-45-6789, 123456789 |credit_card
| | Credit card numbers | 1234-5678-9012-3456, 1234567890123456 |ip_address
| | IP addresses | 192.168.1.1, 2001:0db8:85a3::8a2e:0370:7334 |url
| | URLs | https://example.com, http://sub.domain.org/path |
`javascript`
const anonymizer = new Anonymizer(entityTypes: string[])
- entityTypes: Array of entity types to detect (see supported types above)
#### anonymize(text: string) => AnonymizationResult
Anonymizes the input text using automatic detection and returns detailed result.
Returns:
`typescript
interface AnonymizationResult {
anonymizedText: string; // Text with PII replaced by placeholders
mapping: Record
entities: Entity[]; // Array of detected entities with metadata
}
interface Entity {
entity_type: string; // Type of entity (email, phone, etc.)
value: string; // Original detected value
start: number; // Start position in original text
end: number; // End position in original text
}
`
#### anonymizeWithCustom(text: string, customEntities?: Record
Anonymizes the input text using both automatic detection and custom entities.
Parameters:
- text: The input text to anonymizecustomEntities
- : Optional map of entity types to arrays of custom values to anonymize
Example:
`javascript
const customEntities = {
email: ["secret@company.com", "admin@internal.org"],
phone: ["555-999-0000"]
};
const result = anonymizer.anonymizeWithCustom(text, customEntities);
`
#### deanonymize(text: string, mapping: Record
Restores original text using the provided mapping.
`javascript
const express = require("express");
const { Anonymizer } = require("@anonymask/core");
const app = express();
const anonymizer = new Anonymizer(["email", "phone", "ssn"]);
// Middleware to anonymize request bodies
app.use(express.json());
app.use((req, res, next) => {
if (req.body && req.body.text) {
const result = anonymizer.anonymize(req.body.text);
req.body.anonymized_text = result.anonymized_text;
req.body.pii_mapping = result.mapping;
}
next();
});
app.post("/api/chat", (req, res) => {
// Send req.body.anonymized_text to LLM
// Store req.body.pii_mapping for deanonymization
res.json({ message: "Processed securely" });
});
`
`javascript
const { Anonymizer } = require("@anonymask/core");
class SecureLLMClient {
constructor() {
this.anonymizer = new Anonymizer(["email", "phone", "ssn", "credit_card"]);
}
async processMessage(userMessage, customEntities = null) {
// Anonymize user input with optional custom entities
const result = customEntities
? this.anonymizer.anonymizeWithCustom(userMessage, customEntities)
: this.anonymizer.anonymize(userMessage);
// Send anonymized message to LLM
const llmResponse = await this.callLLM(result.anonymized_text);
// Deanonymize LLM response
const safeResponse = this.anonymizer.deanonymize(
llmResponse,
result.mapping,
);
return safeResponse;
}
}
`
`javascript
const { Anonymizer } = require("@anonymask/core");
// Initialize with basic detection
const anonymizer = new Anonymizer(["email"]);
// Define custom entities to anonymize
const customEntities = {
email: ["internal@company.com", "admin@secure.org"],
phone: ["555-999-0000", "555-888-1111"],
// You can even specify entity types not in the initial list
ssn: ["123-45-6789"]
};
const text = "Contact internal@company.com or call 555-999-0000";
const result = anonymizer.anonymizeWithCustom(text, customEntities);
console.log(result.anonymizedText);
// "Contact EMAIL_xxx or call PHONE_xxx"
console.log(result.mapping);
// { EMAIL_xxx: 'internal@company.com', PHONE_xxx: '555-999-0000' }
`
`javascript
const { Anonymizer } = require("@anonymask/core");
const fs = require("fs").promises;
async function processDataset(filePath) {
const anonymizer = new Anonymizer(["email", "phone", "ssn"]);
const data = await fs.readFile(filePath, "utf8");
const records = JSON.parse(data);
const processedRecords = records.map((record) => {
const result = anonymizer.anonymize(record.text);
return {
...record,
original_text: record.text,
anonymized_text: result.anonymized_text,
pii_mapping: result.mapping,
entities_detected: result.entities.length,
};
});
await fs.writeFile(
"processed_data.json",
JSON.stringify(processedRecords, null, 2),
);
return processedRecords;
}
`
`bashInstall dependencies
npm install
🔧 Development
$3
bash
Clone the repository
git clone https://github.com/gokul-viswanathan/anonymask.git
cd anonymask/anonymask-nodeInstall dependencies
npm installBuild the native addon
npm run buildRun tests
npm test
`$3
anonymask-node/
├── src/
│ └── lib.rs # Rust NAPI bindings
├── index.js # JavaScript entry point
├── index.d.ts # TypeScript definitions
├── tests/
│ └── test_anonymask.test.js # Test suite
├── package.json
└── README.md
🏗️ Architecture
This package uses NAPI-RS to create high-performance Node.js bindings from the Rust core library:
JavaScript/TypeScript → NAPI-RS → Rust Core → Native Performance
The Rust core provides:
- Memory Safety: No buffer overflows or memory leaks
- Performance: Near-native execution speed
- Concurrency: Thread-safe operations
- Reliability: Robust error handling
📊 Performance
- Processing Speed: < 5ms for typical messages (< 500 words)
- Memory Usage: Minimal footprint with zero-copy operations
- Startup Time: Fast initialization with lazy loading
- Concurrency: Safe for use in multi-threaded environments
🔒 Security
- Cryptographically Secure: UUID v4 for unique placeholder generation
- Deterministic: Same input always produces same output
- No Data Leakage: Secure handling of PII throughout the process
- Input Validation: Comprehensive validation and error handling
📄 License
MIT License - see LICENSE file for details.
🤝 Contributing
1. Fork the repository
2. Create a feature branch (
)
3. Add tests for new functionality
4. Ensure all tests pass (npm test`)- [ ] Streaming API for large texts
- [ ] Custom entity pattern support
- [ ] Persistent mapping storage
- [ ] Performance optimizations
- [ ] Additional entity types
- 📖 Documentation
- 🐛 Issue Tracker
- 💬 Discussions
---
Version: 0.4.5 | Built with ❤️ using Rust and NAPI-RS