(Информация о версии неизвестна, возможно, только в SVN)
OAuth::generateSignature — Generate a signature
$http_method
   , string $url
   [, mixed $extra_parameters
  ] )Generate a signature based on the final HTTP method, URL and a string/array of parameters.
http_methodHTTP method for request
urlURL for request
extra_parametersString or array of additional parameters.
   A string containing the generated signature или FALSE в случае возникновения ошибки