PHP使用HMAC-SHA1+base64签名方法

/**
* @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;
    }