求delphi hash_hmac函数

$hash = hash_hmac("sha1", ('GET&'.rawurlencode($Url).'&'.rawurlencode($CanShu)), $SecretOAuthKey.'&', TRUE);

php 有hash_hmac函数 求delphi 版
[解决办法]
http://code.google.com/p/fundamentals/source/browse/trunk/Source/Utils/cHash.pas?r=30