Create ErrorResponse class for error handling

example-app/app/Helpers/ParameterParser.php

@@ -60,7 +60,7 @@ public static function parseEncryptedParams(Request $request): array
         }
 
         $encFileDataBin = null;
-        if (!empty($encFileData)) {
+        if (! empty($encFileData)) {
             if (strlen($encFileData) % 2 !== 0) {
                 throw new \InvalidArgumentException(
                     sprintf('Invalid %s parameter: must have even length', $paramNames['enc_file_data'])
@@ -154,7 +154,7 @@ private static function parseBulkMode(string $bulkParam, string $sdmmacParamName
         }
 
         // Remove the SDMMAC parameter suffix if present
-        $sdmmacSuffix = '&' . $sdmmacParamName . '=';
+        $sdmmacSuffix = '&'.$sdmmacParamName.'=';
         $bulkParam = str_replace($sdmmacSuffix, '', $bulkParam);
 
         // Validate hex string length is even
@@ -197,7 +197,7 @@ private static function parseBulkMode(string $bulkParam, string $sdmmacParamName
     /**
      * Detect encryption mode based on PICC data length.
      *
-     * @param  string  $piccData Binary PICC data
+     * @param  string  $piccData  Binary PICC data
      * @return string 'AES' or 'LRP'
      */
     private static function detectEncryptionMode(string $piccData): string
@@ -216,7 +216,7 @@ private static function detectEncryptionMode(string $piccData): string
     /**
      * Interpret tamper tag status from file data.
      *
-     * @param  string  $fileData Binary file data
+     * @param  string  $fileData  Binary file data
      * @return array{status: string, color: string}|null
      */
     public static function interpretTamperStatus(string $fileData): ?array

example-app/app/Http/Controllers/BaseSDMController.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers;
+
+use KDuma\SDM\SDM;
+
+abstract class BaseSDMController extends Controller
+{
+    /**
+     * Get SDM instance.
+     */
+    protected function getSDM(?string $uid = null): SDM
+    {
+        $factory = app('sdm.factory');
+
+        return $factory($uid);
+    }
+
+    /**
+     * Get master key from configuration.
+     */
+    protected function getMasterKey(): string
+    {
+        $masterKeyHex = config('sdm.master_key');
+        $masterKey = hex2bin($masterKeyHex);
+
+        if ($masterKey === false) {
+            throw new \InvalidArgumentException('Invalid master key format');
+        }
+
+        return $masterKey;
+    }
+
+    /**
+     * Get encryption key.
+     */
+    protected function getEncKey(): string
+    {
+        $masterKey = $this->getMasterKey();
+        $kdf = app(\KDuma\SDM\KeyDerivation::class);
+
+        return $kdf->deriveUndiversifiedKey($masterKey, 1);
+    }
+
+    /**
+     * Get MAC key for a specific UID.
+     */
+    protected function getMacKey(string $uid): string
+    {
+        $masterKey = $this->getMasterKey();
+        $kdf = app(\KDuma\SDM\KeyDerivation::class);
+
+        return $kdf->deriveTagKey($masterKey, $uid, 2);
+    }
+}