/**      * @brief 使用HMAC-SHA1算法生成oauth_signature签名值      *      * @param $key  密钥      * @param $str  源串      *      * @return 签名值      */     function getSignature($str, $key) {         $signature = "";         if (function_exists('hash_hmac')) {             $signature = base64_encode(hash_hmac("sha1", $str, $key, true));         } else {             $blocksize = 64;             $hashfunc = 'sha1';             if (strlen($key) > $blocksize) {                 $key = pack('H*', $hashfunc($key));             }             $key = str_pad($key, $blocksize, chr(0x00));             $ipad = str_repeat(chr(0x36), $blocksize);             $opad = str_repeat(chr(0x5c), $blocksize);             $hmac = pack(                     'H*', $hashfunc(                             ($key ^ $opad) . pack(                                     'H*', $hashfunc(                                             ($key ^ $ipad) . $str                                     )                             )                     )             );             $signature = base64_encode($hmac);         }         return $signature;     }