consent-anonymization

You are a privacy engineering specialist. Implement consent, anonymization, and PETs.

Consent Management

// Consent string (TCF 2.0)
// Purpose IDs: 1=Storage, 3=Personalization, 4=Ad selection...
const consentString = "CPaX9wZPaX9wZAcABBENBkCsAP_AAH_AAAqI3Nf_X_fb39jfH79f7___z3v___9jf___7u___9__1_7___"
// Consent record
{
  "user_id": "anon-uuid",
  "timestamp": "2024-03-15T10:00:00Z",
  "purposes": { "1": true, "3": false, "4": true },
  "legitimate_interests": { "2": true },
  "version": "2.2"
}

Anonymization Techniques

# k-anonymity
def k_anonymize(df, quasi_identifiers: list, k: int = 5):
    """Ensure each combination of QI appears at least k times."""
    counts = df.groupby(quasi_identifiers).size()
    violations = counts[counts < k]
    for idx in violations.index:
        mask = (df[quasi_identifiers] == idx).all(axis=1)
        # Generalize or suppress
    return df

# Differential privacy
import diffprivlib as dp
dp_hist = dp.tools.histogram(data, epsilon=1.0, bins=10)
dp_mean = dp.mechanisms.LaplaceBoundedNoise(epsilon=0.1, bounds=(0, 100))\
    .randomise(original_mean)

# Pseudonymization (reversible)
import hashlib
def pseudonymize(email: str) -> str:
    salt = "static-pepper"
    return hashlib.sha256(f"{email}{salt}".encode()).hexdigest()[:16]

PETs Comparison

| Technique | Privacy | Utility | Performance | Use Case | |-----------|---------|---------|-------------|----------| | K-anonymity | Medium | High | High | Tabular data release | | Differential Privacy | High | Medium | Medium | Statistics, ML | | Homomorphic Encryption | Very High | Low | Very Low | Encrypted computation | | Secure Multi-party Comp | Very High | Medium | Low | Joint computation | | Federated Learning | High | Medium | Medium | ML across orgs | | Synthetic Data | High | High | High | Testing, analytics | | Data Masking | Medium | High | High | Production masking |

Cookie Consent (CCPA)

// CCPA — Opt-out signal (GPC)
// Global Privacy Control header
navigator.globalPrivacyControl?.value  // true if opted out

// CCPA compliance
const ccpa = {
  "notice_at_collection": true,         // Right to know at collection
  "opt_out_sale": true,                 // Right to opt out (12+ months)
  "right_to_delete": true,              // Right to delete
  "right_to_know": true,                // Right to know (12 months)
  "non_discrimination": true            // No retaliation for exercising rights
}