redaction
**Data redaction** is the **process of automatically detecting and removing sensitive information from text, documents, and datasets** — using NLP and pattern matching to identify PII (personally identifiable information), credentials, financial data, and protected health information before sharing, storing, or processing data.
**What Gets Redacted**
- **PII**: Names, addresses, phone numbers, email addresses, SSNs.
- **Financial**: Credit card numbers, bank accounts, salary data.
- **Health (PHI)**: Medical records, diagnoses, treatment information.
- **Credentials**: API keys, passwords, tokens, connection strings.
- **Legal**: Attorney-client privileged communications.
**Redaction Methods**
- **Pattern Matching**: Regex for structured data (SSN: XXX-XX-XXXX).
- **NER (Named Entity Recognition)**: ML models detect names, locations, organizations.
- **LLM-Based**: Use language models to identify contextual sensitive information.
- **Tokenization**: Replace sensitive values with non-reversible tokens.
**Tools**: Microsoft Presidio, AWS Comprehend PII, Google DLP API, spaCy NER.
Data redaction is **essential for privacy compliance** — enabling organizations to share and process data safely while meeting GDPR, HIPAA, and CCPA requirements.