function checkAddress($address)
{
$origbase58 = $address;
$dec = "0";
for ($i = 0; $i < strlen($address); $i++)
{
$dec = bcadd(bcmul($dec,"58",0),strpos("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz",substr($address,$i,1)),0);
}
$address = "";
while (bccomp($dec,0) == 1)
{
$dv = bcdiv($dec,"16",0);
$rem = (integer)bcmod($dec,"16");
$dec = $dv;
$address = $address.substr("0123456789ABCDEF",$rem,1);
}
$address = strrev($address);
for ($i = 0; $i < strlen($origbase58) && substr($origbase58,$i,1) == "1"; $i++)
{
$address = "00".$address;
}
if (strlen($address)%2 != 0)
{
$address = "0".$address;
}
if (strlen($address) != 50)
{
return false;
}
if (hexdec(substr($address,0,2)) > 0)
{
return false;
}
return substr(strtoupper(hash("sha256",hash("sha256",pack("H*",substr($address,0,strlen($address)-8)),true))),0,8) == substr($address,strlen($address)-8);
}
?>
Here is a PHP function to validate a bitcoin address.
