Add Enum class representing Client Authentication Methods.

Author: Potherca

src/Enum/OpenId/AuthenticationMethod.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types=1);
+
+namespace Pdsinterop\Solid\Auth\Enum\OpenId;
+
+/**
+ * Client Authentication Methods
+ *
+ * As described in Section 9 of OpenID Connect Core 1.0 [OpenID.Core]
+ *
+ * Other authentication methods MAY be defined by extensions.
+ *
+ * If omitted, the default is `client_secret_basic` the HTTP Basic
+ * Authentication Scheme specified in Section 2.3.1 of OAuth 2.0 [RFC6749].
+ */
+class AuthenticationMethod
+{
+    public const DEFAULT = self::CLIENT_SECRET_BASIC;
+
+    /** OpenID Connect Core */
+    public const CLIENT_SECRET_BASIC = 'client_secret_basic';
+
+    /** OpenID Connect Core */
+    public const CLIENT_SECRET_JWT = 'client_secret_jwt';
+
+    /** OpenID Connect Core */
+    public const CLIENT_SECRET_POST = 'client_secret_post';
+
+    /** OpenID Connect Core */
+    public const NONE = 'none';
+
+    /** OpenID Connect Core */
+    public const PRIVATE_KEY_JWT = 'private_key_jwt';
+}