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Production/SNIPE-IT/app/LegacyEncrypter/BaseEncrypter.php

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+<?php
+
+namespace App\LegacyEncrypter;
+
+use Illuminate\Contracts\Encryption\DecryptException;
+
+abstract class BaseEncrypter
+{
+    /**
+     * The encryption key.
+     *
+     * @var string
+     */
+    protected $key;
+
+    /**
+     * Create a MAC for the given value.
+     *
+     * @param  string  $iv
+     * @param  string  $value
+     * @return string
+     */
+    protected function hash($iv, $value)
+    {
+        return hash_hmac('sha256', $iv.$value, $this->key);
+    }
+
+    /**
+     * Get the JSON array from the given payload.
+     *
+     * @param  string  $payload
+     * @return array
+     *
+     * @throws \Illuminate\Contracts\Encryption\DecryptException
+     */
+    protected function getJsonPayload($payload)
+    {
+        $payload = json_decode(base64_decode($payload), true);
+
+        // If the payload is not valid JSON or does not have the proper keys set we will
+        // assume it is invalid and bail out of the routine since we will not be able
+        // to decrypt the given value. We'll also check the MAC for this encryption.
+        if (! $payload || $this->invalidPayload($payload)) {
+            throw new DecryptException('The payload is invalid.');
+        }
+
+        if (! $this->validMac($payload)) {
+            throw new DecryptException('The MAC is invalid.');
+        }
+
+        return $payload;
+    }
+
+    /**
+     * Verify that the encryption payload is valid.
+     *
+     * @param  array|mixed  $data
+     * @return bool
+     */
+    protected function invalidPayload($data)
+    {
+        return ! is_array($data) || ! isset($data['iv']) || ! isset($data['value']) || ! isset($data['mac']);
+    }
+
+    /**
+     * Determine if the MAC for the given payload is valid.
+     *
+     * @param  array  $payload
+     * @return bool
+     *
+     * @throws \RuntimeException
+     */
+    protected function validMac(array $payload)
+    {
+        $bytes = random_bytes(16);
+
+        $calcMac = hash_hmac('sha256', $this->hash($payload['iv'], $payload['value']), $bytes, true);
+
+        return hash_equals(hash_hmac('sha256', $payload['mac'], $bytes, true), $calcMac);
+    }
+}