使用HMAC-SHA1签名方法详解

   /**
    *@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
    */
   functiongetSignature($str,$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;
   }