signature: generate dependencies for signature header

src/Requests/Header.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Msr\LaravelBitunixApi\Requests;
+
+class Header
+{
+    public static function sortQueryParameters(array $parameters): ?array
+    {
+        $sortableParameters = $parameters;
+
+        if (!count($sortableParameters)) {
+            return [];
+        }
+
+        ksort($sortableParameters, SORT_LOCALE_STRING);
+        return $sortableParameters;
+    }
+
+    public static function digestQueryParameters(array $parameters): ?string
+    {
+        if (!count($parameters)) {
+            return null;
+        }
+
+        $sortedParameters = self::sortQueryParameters($parameters);
+        return implode('', array_map(
+            fn($k, $v) => $k . $v,
+            array_keys($sortedParameters),
+            array_values($sortedParameters)
+        ));
+    }
+
+    public static function generateNonce(): ?string
+    {
+        return md5(uniqid(mt_rand(), true));
+    }
+}