PCI DSS Compliance for Payment Processing

PCI DSS Compliance for Payment Processing

Payment Card Industry Data Security Standard compliance is mandatory for apps handling credit card data.

// Android - PCI DSS compliance implementation
class PCIDSSCompliance(private val context: Context) {
    
    // PCI DSS Requirement 1: Firewall Configuration
    class NetworkSecurityConfig {
        fun generateSecurityConfig(): String {
            return """
                <?xml version="1.0" encoding="utf-8"?>
                <network-security-config>
                    <base-config cleartextTrafficPermitted="false">
                        <trust-anchors>
                            <certificates src="system" />
                        </trust-anchors>
                    </base-config>
                    
                    <!-- Pin certificates for payment endpoints -->
                    <domain-config>
                        <domain includeSubdomains="true">payment.example.com</domain>
                        <pin-set expiration="2025-01-01">
                            <pin digest="SHA-256">AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=</pin>
                            <pin digest="SHA-256">BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB=</pin>
                        </pin-set>
                        <trustkit-config>
                            <report-uri>https://report.example.com/pin-failure</report-uri>
                        </trustkit-config>
                    </domain-config>
                </network-security-config>
            """.trimIndent()
        }
    }
    
    // PCI DSS Requirement 2: Default Security Parameters
    class SecurityConfiguration {
        
        fun hardenApplication() {
            // Remove default accounts
            removeDefaultAccounts()
            
            // Disable unnecessary services
            disableUnnecessaryServices()
            
            // Configure secure defaults
            configureSecureDefaults()
        }
        
        private fun configureSecureDefaults() {
            // Encryption settings
            SecurityConfig.apply {
                setMinimumTLSVersion(TlsVersion.TLS_1_2)
                setPreferredCipherSuites(
                    listOf(
                        CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
                        CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
                    )
                )
                
                // Key management
                setKeyRotationInterval(90) // days
                setKeyDerivationIterations(100_000)
            }
        }
    }
    
    // PCI DSS Requirement 3: Protect Cardholder Data
    class CardholderDataProtection {
        
        // Never store sensitive authentication data
        private val prohibitedData = setOf(
            "cvv", "cvv2", "cvc", "cvc2", "cid",
            "pin", "pin_block",
            "track1", "track2", "track3"
        )
        
        fun processPaymentData(cardData: CardData): ProcessedPayment {
            // Validate card data
            validateCardData(cardData)
            
            // Tokenize immediately
            val token = tokenizeCard(cardData)
            
            // Clear sensitive data from memory
            cardData.secureWipe()
            
            return ProcessedPayment(
                token = token,
                lastFourDigits = cardData.number.takeLast(4),
                expiryMonth = cardData.expiryMonth,
                expiryYear = cardData.expiryYear,
                cardholderName = maskName(cardData.cardholderName)
            )
        }
        
        private fun tokenizeCard(cardData: CardData): String {
            // Use payment processor's tokenization
            val tokenRequest = TokenizationRequest(
                number = cardData.number,
                expiryMonth = cardData.expiryMonth,
                expiryYear = cardData.expiryYear,
                cvv = cardData.cvv
            )
            
            // Send over encrypted channel only
            return PaymentGateway.tokenize(tokenRequest)
        }
        
        // Data retention and disposal
        fun implementDataRetention() {
            DataRetentionPolicy.configure(
                tokenizedCards = RetentionPeriod.Days(365),
                transactionLogs = RetentionPeriod.Days(365),
                auditLogs = RetentionPeriod.Years(3)
            )
            
            // Secure deletion
            DataDisposal.configure(
                method = DisposalMethod.CRYPTOGRAPHIC_ERASURE,
                verification = true,
                certification = true
            )
        }
    }
    
    // PCI DSS Requirement 4: Encrypt transmission
    class TransmissionEncryption {
        
        fun setupSecureTransmission() {
            val paymentApiClient = OkHttpClient.Builder()
                .addInterceptor(PCIInterceptor())
                .connectionSpecs(listOf(
                    ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
                        .tlsVersions(TlsVersion.TLS_1_2, TlsVersion.TLS_1_3)
                        .cipherSuites(
                            CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
                            CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
                        )
                        .build()
                ))
                .certificatePinner(createCertificatePinner())
                .build()
        }
        
        inner class PCIInterceptor : Interceptor {
            override fun intercept(chain: Interceptor.Chain): Response {
                val request = chain.request()
                
                // Ensure HTTPS only
                if (request.url.scheme != "https") {
                    throw SecurityException("Payment data must be transmitted over HTTPS")
                }
                
                // Add security headers
                val secureRequest = request.newBuilder()
                    .header("X-Content-Type-Options", "nosniff")
                    .header("X-Frame-Options", "DENY")
                    .header("Strict-Transport-Security", "max-age=31536000; includeSubDomains")
                    .build()
                
                val response = chain.proceed(secureRequest)
                
                // Validate response
                validateSecureResponse(response)
                
                return response
            }
        }
    }
    
    // PCI DSS Requirement 8: Identify and authenticate access
    class AccessControl {
        
        fun implementStrongAuthentication() {
            // Multi-factor authentication for payment access
            val mfaManager = MFAManager(context)
            
            mfaManager.configure(
                factors = listOf(
                    AuthFactor.PASSWORD(
                        minLength = 12,
                        requireUppercase = true,
                        requireLowercase = true,
                        requireNumbers = true,
                        requireSpecialChars = true,
                        preventReuse = 4
                    ),
                    AuthFactor.BIOMETRIC,
                    AuthFactor.OTP(
                        algorithm = OTPAlgorithm.TOTP,
                        digits = 6,
                        period = 30
                    )
                ),
                requiredFactors = 2
            )
            
            // Session management
            SessionManager.configure(
                maxIdleTime = 15 * 60, // 15 minutes
                absoluteTimeout = 8 * 60 * 60, // 8 hours
                lockoutPolicy = LockoutPolicy(
                    maxAttempts = 6,
                    lockoutDuration = 30 * 60 // 30 minutes
                )
            )
        }
    }
    
    // PCI DSS Requirement 10: Track and monitor access
    class AuditLogging {
        
        private val secureLogger = SecureAuditLogger()
        
        fun logPaymentEvent(event: PaymentEvent) {
            val auditEntry = AuditEntry(
                timestamp = System.currentTimeMillis(),
                eventType = event.type,
                userId = event.userId,
                sourceIP = event.sourceIP,
                outcome = event.outcome,
                affectedData = event.affectedData.map { it.tokenized() },
                details = event.details
            )
            
            // Tamper-proof logging
            secureLogger.log(
                entry = auditEntry,
                signature = generateSignature(auditEntry),
                encryption = true
            )
        }
        
        fun configureLogRetention() {
            secureLogger.setRetention(
                period = RetentionPeriod.Years(3),
                archival = true,
                integrityChecks = true
            )
        }
    }
}