WordPress Rest API: How do we validate with our custom API key?

function checkApiAuth( $result ){

    $yourEncryptAPIKey = $_GET['request'];

    if( yourDecryptFn( $yourEncryptAPIKey ) === $realKey ):
        $result = true;

    else:
        $result = false;

    endif;

    return $result;           
}
add_filter('rest_authentication_errors', 'checkApiAuth');