README

GDPR-compliant audit logging for PHP with injectable encryption, configurable storage, and tamper-proof checksums.

Features

• GDPR compliant - Supports Art. 15, 17, 30, 32, 33
• Injectable encryption - AppEncryption (AES-256-GCM) or DatabaseEncryption
• Tamper-proof - HMAC-SHA-256 checksums with verify() method
• Configurable - Custom table name, optional file logging
• Null Object - NullAuditLogger for environments without audit requirements
• Zero dependencies - Only requires ext-pdo (stdlib)
• Both PostgreSQL and MariaDB - Migration SQL included

Installation

composer require zappzarapp/audit-logger

Quick Start

use Zappzarapp\AuditLogger\AuditLogger;
use Zappzarapp\AuditLogger\AuditLogEntry;

$auditLogger = new AuditLogger(
    pdo: $pdo,
    encryptionKey: $_ENV['ENCRYPTION_KEY'],
);

// Log a data access event
$auditLogger->log(new AuditLogEntry(
    action: 'user.view',
    entityType: 'user',
    entityId: 123,
    userId: $currentUserId,
    ipAddress: $request->getClientIp(),
    userAgent: $request->getUserAgent(),
));

// Log authentication
$auditLogger->logAuth(
    action: 'login.success',
    userId: $userId,
    ipAddress: $request->getClientIp(),
    userAgent: $request->getUserAgent(),
);

// Log admin action
$auditLogger->logAdmin(
    action: 'role.granted',
    adminUserId: $adminId,
    entityType: 'user',
    entityId: $targetUserId,
    data: ['role' => 'moderator'],
);

// Query logs
$logs = $auditLogger->getLogsForEntity('user', 123);
$userLogs = $auditLogger->getLogsForUser($userId);

// Verify integrity
foreach ($logs as $log) {
    if (!$auditLogger->verify($log)) {
        // Tampered entry detected!
    }
}

Configuration

use Zappzarapp\AuditLogger\AuditLogger;
use Zappzarapp\AuditLogger\Encryption\AppEncryption;
use Zappzarapp\AuditLogger\Encryption\DatabaseEncryption;

// Full configuration
$auditLogger = new AuditLogger(
    pdo: $pdo,
    encryptionKey: $_ENV['ENCRYPTION_KEY'],
    encryption: new AppEncryption(),    // default (AES-256-GCM in PHP)
    tableName: 'audit_logs',            // default table name
    logFilePath: '/var/log/audit.log',  // optional file logging (null = disabled)
);

// Using database-level encryption (for existing encrypt_text() setups)
$auditLogger = new AuditLogger(
    pdo: $pdo,
    encryptionKey: $_ENV['ENCRYPTION_KEY'],
    encryption: new DatabaseEncryption(),
);

// Disable audit logging (Null Object pattern)
$auditLogger = new NullAuditLogger();

Note: File logging (logFilePath) does not include log rotation. Configure external rotation (e.g. logrotate) to prevent unbounded file growth.

Example /etc/logrotate.d/audit-logger:

/var/log/audit.log {
    daily
    rotate 90
    compress
    delaycompress
    missingok
    notifempty
    copytruncate
}

Note: The library does not set query timeouts on the injected PDO connection. Configure timeouts at the connection level to prevent indefinite blocking:

// PostgreSQL
$pdo->exec('SET statement_timeout = 5000'); // 5 seconds

// MariaDB / MySQL
$pdo = new PDO($dsn, $user, $pass, [
    PDO::ATTR_TIMEOUT => 5,
]);

Database Setup

Apply the migration for your database:

• PostgreSQL: migrations/postgresql/audit_logs.sql
• MariaDB: migrations/mariadb/audit_logs.sql

Documentation

• GDPR Compliance - GDPR articles covered, purge/retention guidance
• Database Encryption - Migration from DB-level encryption

Development

make install    # Install dependencies
make test       # Run tests
make analyse    # PHPStan static analysis
make cs-check   # Code style check
make check      # All quality checks
make check-full # Including mutation testing

License

MIT