Complete my HMAC decryption in PHP -- 2

We are looking for a PHP version of the google HMAC encrypt method described in this link [login to view URL] Our supplier deliverd some keys to test the algorytm. e_key = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa i_key = bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb data = qMgSYozqy_iTLthA_kqjsm_Y7PlGcHiO4UU9aw== I wrote a piece of code, but i can't find the answer why it is not working. Probably the php base64 encoding algorithm in PHP is not supporting RFC 3548. When the method is implemented correctly the result has to be a number with decimals. When i execute my method with the above data the output is gibberish. We’re looking for a work-around. Hereby our code //[login to view URL] function hmacEncrypt($price, $iv, $e_key, $i_key) { $pad = substr(hash_hmac('sha1', $iv, $e_key), 0, 8); $enc_price = $pad ^ $price; $signature = substr(hash_hmac('sha1', $price . $iv, $i_key), 0, 4); $final_message = base64_encode($iv . $enc_price . $signature); return $final_message; } function hmacDecrypt($final_message, $e_key, $i_key) { //$enc_price = base64_decode($final_message); $enc_price = base64_decode($final_message, 16); $iv = substr($enc_price, 0, 16); $signature = substr($enc_price, strlen($enc_price) - 4, 4); $p = substr($enc_price, 16, 8); $price_pad = substr(hash_hmac('sha1', $iv, $e_key), 0, 8); $price = $p ^ $price_pad; $conf_sig = substr(hash_hmac('sha1', $price . $iv, $i_key), 0, 4); return $price; if ($conf_sig === $signature) { return floatval($price); } } echo hmacDecrypt('qMgSYozqy_iTLthA_kqjsm_Y7PlGcHiO4UU9aw==', 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb');