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PII & Privacy Protection

KAIU’s AI system automatically redacts Personally Identifiable Information (PII) from conversation histories before storing them in the database. This ensures customer privacy and compliance with data protection regulations.

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Why Redact PII?

Privacy First: PII is redacted from the conversation history stored in sessionContext, but the original message is still sent to Claude for immediate processing. This balances privacy with functionality.

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PII Filter Implementation

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Redaction Function (pii-filter.js:1-23)

export const redactPII = (text) => {
    if (!text) return text;

    let redacted = text;

    // 1. Emails
    const emailRegex = /\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/g;
    redacted = redacted.replace(emailRegex, "[REDACTED EMAIL]");

    // 2. Phone Numbers (Colombian mobile format)
    // Matches: 3xx xxx xxxx, +57 3xx..., 3xxxxxxxxx
    const phoneRegex = /(?:\+57|57)?\s?3[0-9]{2}[\s\-]?[0-9]{3}[\s\-]?[0-9]{4}/g;
    redacted = redacted.replace(phoneRegex, "[REDACTED PHONE]");

    // 3. Credit Cards (commented out to avoid false positives)
    // const ccRegex = /\b(?:\d[ -]*?){13,16}\b/g;
    // redacted = redacted.replace(ccRegex, "[REDACTED CARD]");
    // Avoided to prevent matching product codes or tracking numbers

    return redacted;
};

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Supported PII Types

Email Addresses

Matches standard email formats (RFC 5322 simplified)Pattern: [A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}

Phone Numbers

Matches Colombian mobile numbers with various formatsPattern: (?:\+57|57)?\s?3[0-9]{2}[\s\-]?[0-9]{3}[\s\-]?[0-9]{4}

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Redaction Examples

Input:  "Mi correo es [email protected]"
Output: "Mi correo es [REDACTED EMAIL]"

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Integration in Queue Worker

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Before Storage (queue.js:67-71)

// 3. Append User Message
// Redact PII before storing in history (Context Window Privacy)
const cleanText = redactPII(text);

const userMsg = { role: 'user', content: cleanText };
history.push(userMsg);

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Original vs. Redacted

StageContent Used
Immediate Claude API CallOriginal text (for accurate processing)
Database StorageRedacted cleanText (for privacy)
Dashboard DisplayOriginal text (real-time, not from history)
Future ContextRedacted cleanText (from session history)
The current message is sent to Claude with the original text for accurate processing. Only the stored history is redacted.

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Why Credit Cards Are Disabled

The credit card regex is commented out to avoid false positives: 
// 3. Credit Cards (Luhn algorithm checks are complex, simple regex for 13-16 digits)
const ccRegex = /\b(?:\d[ -]*?){13,16}\b/g;
// Commented out to avoid false positives on product codes or tracking numbers without more context.
// Let's stick to emails and phones for now which are high risk.
Reasons:
  • Product SKUs often have long numeric sequences
  • Tracking numbers could be falsely matched
  • No Luhn algorithm validation (would match random 16-digit strings)
For production, integrate a Luhn validator before redacting card numbers:
import { luhn } from 'luhn-js';

if (luhn.validate(match)) {
    redacted = redacted.replace(match, "[REDACTED CARD]");
}

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Extending PII Protection

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Adding Colombian ID Numbers (Cédula)

export const redactPII = (text) => {
    if (!text) return text;
    let redacted = text;

    // Existing email and phone redaction...

    // 3. Colombian ID (Cédula)
    // Matches 6-10 digit sequences (common range)
    const cedulaRegex = /\b[0-9]{6,10}\b/g;
    redacted = redacted.replace(cedulaRegex, "[REDACTED ID]");

    return redacted;
};
Be careful with numeric redaction - it may affect order numbers, product codes, or quantities.

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Adding Address Redaction

// 4. Street Addresses (Spanish)
const addressRegex = /\b(calle|carrera|avenida|transversal|diagonal)\s+[0-9]+[a-z]?\s*(#|no\.?)\s*[0-9]+[a-z]?\s*-\s*[0-9]+/gi;
redacted = redacted.replace(addressRegex, "[REDACTED ADDRESS]");

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Adding Name Redaction (Advanced)

For name detection, use a Named Entity Recognition (NER) library: 
import { nlp } from 'compromise';

export const redactPII = (text) => {
    if (!text) return text;
    let redacted = text;

    // Email and phone redaction...

    // 4. Names (NER)
    const doc = nlp(text);
    const names = doc.people().out('array');
    
    names.forEach(name => {
        redacted = redacted.replace(new RegExp(`\\b${name}\\b`, 'gi'), "[REDACTED NAME]");
    });

    return redacted;
};

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Testing PII Redaction

import { redactPII } from '../utils/pii-filter.js';

const testCases = [
    {
        input: "Mi email es [email protected]",
        expected: "Mi email es [REDACTED EMAIL]"
    },
    {
        input: "Llámame al 321 456 7890",
        expected: "Llámame al [REDACTED PHONE]"
    },
    {
        input: "Contacto: +57 310-123-4567 o [email protected]",
        expected: "Contacto: [REDACTED PHONE] o [REDACTED EMAIL]"
    },
    {
        input: "¿Tienen lavanda?",
        expected: "¿Tienen lavanda?"
    }
];

testCases.forEach(({ input, expected }) => {
    const result = redactPII(input);
    console.assert(result === expected, `Failed: ${input}`);
    console.log(`✅ ${input} → ${result}`);
});

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Database Privacy

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Session Context Structure

{
  "history": [
    {
      "role": "user",
      "content": "Hola, quiero información sobre lavanda"
    },
    {
      "role": "assistant",
      "content": "¡Claro! Tenemos Aceite Esencial Lavanda en 10ml..."
    },
    {
      "role": "user",
      "content": "Perfecto, mi correo es [REDACTED EMAIL]" // PII redacted
    }
  ]
}

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Querying Redacted History

const session = await prisma.whatsAppSession.findUnique({
    where: { phoneNumber: '+57 321 456 7890' },
    select: {
        id: true,
        sessionContext: true // Contains redacted history
    }
});

const history = session.sessionContext?.history || [];
// PII already redacted in stored messages

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Compliance Considerations

GDPR

Redaction helps with data minimization principle by not storing unnecessary PII

CCPA

Reduces risk of PII exposure in database backups and logs

Local Regulations

Complies with Colombian data protection laws (Ley 1581 de 2012)

Right to Erasure

Simplifies GDPR “Right to be Forgotten” requests

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Logging Privacy

Ensure PII is also redacted from logs: 
// Good: Redact before logging
console.log(`Processing message: "${redactPII(text)}"`);

// Bad: Logs raw PII
console.log(`Processing message: "${text}"`);

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Real-time Dashboard

The Socket.IO dashboard receives original messages in real-time: 
// queue.js:74-80
if (io) {
    io.to(`session_${session.id}`).emit('new_message', { 
        sessionId: session.id, 
        message: { role: 'user', content: text, time: "Just now" } // Original text
    });
}
Real-time messages are not stored - they’re only for live monitoring. Agents see the original message, but it’s not persisted.

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Best Practices

Redact Early

Apply redaction immediately before storage, not at query time

Test Thoroughly

Create comprehensive test cases for all PII patterns

Avoid Over-Redaction

Balance privacy with functionality (don’t redact product codes)

Audit Regularly

Periodically review stored histories for PII leaks

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Next Steps

Architecture

Understand how PII redaction fits into the overall system

Setup

Configure environment variables and database

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