src/Core/OAuth/OAuth1/OAuth1.php
public function signUsingHmacSha1($baseString){
       $key = rawurlencode($this->consumerSecret) . '&' . rawurlencode($this->oauthTokenSecret);
       return base64_encode(hash_hmac(self::SIGNATURE_METHOD, $baseString, $key, TRUE));
  }
public function signUsingHmacSha1($baseString){
       $key = rawurlencode($this->consumerSecret) . '&' . rawurlencode($this->oauthTokenSecret);
       return base64_encode(hash_hmac(self::SIGNATURE_METHOD, $baseString, $key, TRUE));
  }
Sign the $baseString with HMAC-SHA1
@param String $baseString    The baseString to be signed
@return String Signed String