PCI Compliance

Master PCI DSS (Payment Card Industry Data Security Standard) compliance for secure payment processing and handling of cardholder data.

Do not use this skill when

• The task is unrelated to pci compliance
• You need a different domain or tool outside this scope

Instructions

• Clarify goals, constraints, and required inputs.
• Apply relevant best practices and validate outcomes.
• Provide actionable steps and verification.
• If detailed examples are required, open resources/implementation-playbook.md.

Use this skill when

• Building payment processing systems
• Handling credit card information
• Implementing secure payment flows
• Conducting PCI compliance audits
• Reducing PCI compliance scope
• Implementing tokenization and encryption
• Preparing for PCI DSS assessments

PCI DSS Requirements (12 Core Requirements)

Build and Maintain Secure Network

1. Install and maintain firewall configuration
2. Don't use vendor-supplied defaults for passwords

Protect Cardholder Data

1. Protect stored cardholder data
2. Encrypt transmission of cardholder data across public networks

Maintain Vulnerability Management

1. Protect systems against malware
2. Develop and maintain secure systems and applications

Implement Strong Access Control

1. Restrict access to cardholder data by business need-to-know
2. Identify and authenticate access to system components
3. Restrict physical access to cardholder data

Monitor and Test Networks

1. Track and monitor all access to network resources and cardholder data
2. Regularly test security systems and processes

Maintain Information Security Policy

1. Maintain a policy that addresses information security

Compliance Levels

Level 1: > 6 million transactions/year (annual ROC required) Level 2: 1-6 million transactions/year (annual SAQ) Level 3: 20,000-1 million e-commerce transactions/year Level 4: < 20,000 e-commerce or < 1 million total transactions

Data Minimization (Never Store)

# NEVER STORE THESE
PROHIBITED_DATA = {
    'full_track_data': 'Magnetic stripe data',
    'cvv': 'Card verification code/value',
    'pin': 'PIN or PIN block'
}

# CAN STORE (if encrypted)
ALLOWED_DATA = {
    'pan': 'Primary Account Number (card number)',
    'cardholder_name': 'Name on card',
    'expiration_date': 'Card expiration',
    'service_code': 'Service code'
}

class PaymentData:
    """Safe payment data handling."""

    def __init__(self):
        self.prohibited_fields = ['cvv', 'cvv2', 'cvc', 'pin']

    def sanitize_log(self, data):
        """Remove sensitive data from logs."""
        sanitized = data.copy()

        # Mask PAN
        if 'card_number' in sanitized:
            card = sanitized['card_number']
            sanitized['card_number'] = f"{card[:6]}{'*' * (len(card) - 10)}{card[-4:]}"

        # Remove prohibited data
        for field in self.prohibited_fields:
            sanitized.pop(field, None)

        return sanitized

    def validate_no_prohibited_storage(self, data):
        """Ensure no prohibited data is being stored."""
        for field in self.prohibited_fields:
            if field in data:
                raise SecurityError(f"Attempting to store prohibited field: {field}")

Tokenization

Using Payment Processor Tokens

```python import stripe

class TokenizedPayment: """Handle payments using tokens (no card data on server)."""

@staticmethod
def create_payment_method_token(card_details):
    """Create token from card details (client-side only)."""
    # THIS SHOULD ONLY BE DONE CLIENT-SIDE WITH STRIPE.JS
    # NEVER send card details to your server

    """
    // Frontend JavaScript
    const stripe = Stripe('pk_...');

    const {token, error} = await stripe.createToken({
        card: {
            number: '4242424242424242',
            exp_month: 12,
            exp_year: 2024,
            cvc: '123'
        }
    });

    // Send token.id to server (NOT card details)
    """
    pass

@staticmethod
def charge_with_token(token_id, amount):
    """Charge using token (server-side)."""
    # Your server only sees the token, never the card number
    stripe.api_key = "sk_..."

    charge = stripe.Charge.create(
        amount=amount,
        currency="usd",
        source=token_id,  # Token instead of card details
        description="Payment"
    )

    return charge

@staticmethod
def store_payment_method(customer_id, payment_method_token):
    """Store payment method as token for future use."""
    stripe.Customer.modify(
        customer_id,
        source=payment_method_token
    )

    # Store only customer_id and payment_method_id in your database
    # NEVER store actual card details
    return {
        'customer_id': customer_id,
        'has_payment_method': True