diff --git a/src/plugin_api/auth_api.h b/src/plugin_api/auth_api.h
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+++ b/src/plugin_api/auth_api.h
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+/*
+ * uhub - A tiny ADC p2p connection hub
+ * Copyright (C) 2007-2010, Jan Vidar Krey
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef HAVE_UHUB_PLUGIN_AUTH_H
+#define HAVE_UHUB_PLUGIN_AUTH_H
+
+enum user_credentials
+{
+	cred_none,                 /**<<< "User has no credentials (not yet logged in)" */
+ 	cred_bot,                  /**<<< "User is a robot" */
+	cred_guest,                /**<<< "User is a guest (unregistered user)" */
+ 	cred_user,                 /**<<< "User is identified as a registered user" */
+	cred_operator,             /**<<< "User is identified as a hub operator" */
+	cred_super,                /**<<< "User is a super user" (not used) */
+	cred_link,                 /**<<< "User is a link (not used currently)" */
+	cred_admin,                /**<<< "User is identified as a hub administrator/owner" */
+};
+
+struct uhub_plugin_auth_info
+{
+	char* nickname;
+	char* password;
+	enum user_credentials credentials;
+};
+
+#define UHUB_AUTH_PLUGIN_VERSION 0
+
+/**
+ * Returns the version number of the uhub auth plugin.
+ */
+extern int uhub_plugin_auth_version();
+
+/**
+ * Returns a struct user_plugin_auth_info with nickname, password and credentials
+ * for a given user's nickname.
+ * In case the user is not registered NULL is returned.
+ *
+ * @returns A relevant uhub_plugin_auth_info with password and credentials, or NULL
+ *          if the user is not found in the auth database.
+ */
+extern struct uhub_plugin_auth_info* uhub_plugin_auth_get_user(const char* nickname);
+
+/**
+ * Register a new user.
+ * 
+ * @param user contains nickname, password and credentials for a user.
+ * @returns 0 on success
+ *          <0 if an error occured
+ */
+extern int uhub_plugin_auth_register_user(struct uhub_plugin_auth_info* user);
+
+/**
+ * Update password and user credentials.
+ *
+ * @param user contains nickname and new password.
+ * @returns 0 on success
+ *          <0 if an error occured
+ */
+extern int uhub_plugin_auth_update_info(struct uhub_plugin_auth_info* user);
+
+
+#endif /* HAVE_UHUB_PLUGIN_AUTH_H */
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