Mcrypt deprecated in user_saml app?

I am trying to get the SSO authentication working using the user_saml app and am running into a bit of trouble, I have applied the settings within the SSO tab (SP and IdP certs, uid binding, IdP URLs and selected all the checkboxes of the second ‘required’ section) and have configured a trust relationship within the IdP… I can now access my nextcloud install via URL and am redirected to the IdP login page, after successful login I am redirected back to ‘https://mynextcloud.com/apps/user_saml/saml/acs’ where I receive the error

invalid_response
Not authenticated

After looking at the logs I am finding that each of these functions are giving the same deprecated function…

Function mcrypt_module_close() is deprecated at $HOME/apps/user_saml/3rdparty/vendor/onelogin/php-saml/extlib/xmlseclibs/xmlseclibs.php#328
Function mcrypt_generic_deinit() is deprecated at $HOME/apps/user_saml/3rdparty/vendor/onelogin/php-saml/extlib/xmlseclibs/xmlseclibs.php#328
Function mdecrypt_generic() is deprecated at $HOME/apps/user_saml/3rdparty/vendor/onelogin/php-saml/extlib/xmlseclibs/xmlseclibs.php#328
Function mcrypt_generic_init() is deprecated at $HOME/apps/user_saml/3rdparty/vendor/onelogin/php-saml/extlib/xmlseclibs/xmlseclibs.php#328
Function mcrypt_enc_get_iv_size() is deprecated at $HOME/apps/user_saml/3rdparty/vendor/onelogin/php-saml/extlib/xmlseclibs/xmlseclibs.php#328
Function mcrypt_module_open() is deprecated at $HOME/apps/user_saml/3rdparty/vendor/onelogin/php-saml/extlib/xmlseclibs/xmlseclibs.php#328

Is there a workaround for this?

Thanks in advance

There is work-in-progress to remove the mcrypt dependency at https://github.com/onelogin/php-saml/tree/remove_mcrypt

However, your error seems to be rather caused by a configuration error. Even though the functions are deprecated the app should still work just fine.