Privacy by Design and Default Questions

// Node.js / JavaScript implementation
const REDACTED = '[REDACTED]';

/**
 * Redact PII from obj according to redactionPaths (e.g. ['user.email','payment.card.number'])
 * Returns a new object, does not mutate input.
 */
function redactPII(obj, redactionPaths) {
  const pathTrees = buildPathTree(redactionPaths);
  return redactNode(obj, pathTrees);
}

function buildPathTree(paths) {
  // Build a trie-like tree for fast matching
  const root = {};
  for (const p of paths) {
    const parts = p.split('.');
    let node = root;
    for (const part of parts) {
      node[part] = node[part] || {};
      node = node[part];
    }
    node.__redact = true;
  }
  return root;
}

function redactNode(node, pathTree) {
  // primitive or null -> return as-is
  if (node === null || typeof node !== 'object') return node;

  if (Array.isArray(node)) {
    // map each element, applying same pathTree
    return node.map(el => redactNode(el, pathTree));
  }

  // object: copy keys; for each key check pathTree
  const out = {};
  for (const [k, v] of Object.entries(node)) {
    if (pathTree && pathTree[k]) {
      if (pathTree[k].__redact) {
        // redact the whole value at this path
        out[k] = REDACTED;
      } else {
        // descend with the subtree for this key
        out[k] = redactNode(v, pathTree[k]);
      }
    } else {
      // key not in any redaction path: still need to deep-copy to avoid mutation
      out[k] = redactNode(v, null);
    }
  }
  return out;
}

def process_log(record):
    if regex_high_precision_match(record.text):
        return action_quarantine(record, reason="regex")
    features = featurize(record.text)            # tokens, pos, embeddings
    preds, probs = ner_model.predict_proba(features)
    score = combine_scores(regex_score(record), probs)
    if score >= QUARANTINE_THRESH:
        return action_quarantine(record, reason="ml", score=score)
    elif score >= REDACT_THRESH:
        return action_redact(record, preds)
    else:
        return action_allow(record)