As a reference for other readers rosettacode has a resource on how to verify a bitcoin address in 20 different programming languages.
https://rosettacode.org/wiki/Bitcoin/address_validation
Topic: [Help] Bitcoin address validation (Read 892 times)
Thank you all very much solved it 
If someone have the same trouble here you go:
function ValidateBTC($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);
}
If someone have the same trouble here you go:
Quote
function ValidateBTC($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);
}
Hello I have on my site bitcoin address validation but it's not working I don't know why. When I enter valid address it shows that this address not valid. 
There is code:
Please help.
There is code:
Quote
function ValidateBTC($address){
$decoded = decodeBase58($address);
$d1 = hash("sha256", substr($decoded,0,21), true);
$d2 = hash("sha256", $d1, true);
if(substr_compare($decoded, $d2, 21, 4)) Message(1, 'Invalid bitcoin wallet adress.');
return true;
}
function decodeBase58($input) {
$alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
$out = array_fill(0, 25, 0);
for($i=0;$i
$c = $p;
for ($j = 25; $j--; ) {
$c += (int)(58 * $out[$j]);
$out[$j] = (int)($c % 256);
$c /= 256;
$c = (int)$c;
}
if($c != 0) Message(1, 'Invalid bitcoin wallet adress.');
}
$result = "";
foreach($out as $val) $result .= chr($val);
return $result;
}
$decoded = decodeBase58($address);
$d1 = hash("sha256", substr($decoded,0,21), true);
$d2 = hash("sha256", $d1, true);
if(substr_compare($decoded, $d2, 21, 4)) Message(1, 'Invalid bitcoin wallet adress.');
return true;
}
function decodeBase58($input) {
$alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
$out = array_fill(0, 25, 0);
for($i=0;$i
$c = $p;
for ($j = 25; $j--; ) {
$c += (int)(58 * $out[$j]);
$out[$j] = (int)($c % 256);
$c /= 256;
$c = (int)$c;
}
if($c != 0) Message(1, 'Invalid bitcoin wallet adress.');
}
$result = "";
foreach($out as $val) $result .= chr($val);
return $result;
}
Please help.
You can also check your address at blockchain . Its the best place to check for the btc transcations.
Hope it helps.
I think you are just comparing it incorrectly. You need to compare the first 4 bytes of the double sha256 hash to the last 4 bytes of the decoded address.
Also, a byte is two characters, not one.
Also, a byte is two characters, not one.
Hello I have on my site bitcoin address validation but it's not working I don't know why. When I enter valid address it shows that this address not valid.
There is code:
Please help.
There is code:
Quote
function ValidateBTC($address){
$decoded = decodeBase58($address);
$d1 = hash("sha256", substr($decoded,0,21), true);
$d2 = hash("sha256", $d1, true);
if(substr_compare($decoded, $d2, 21, 4)) Message(1, 'Invalid bitcoin wallet adress.');
return true;
}
function decodeBase58($input) {
$alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
$out = array_fill(0, 25, 0);
for($i=0;$i
$c = $p;
for ($j = 25; $j--; ) {
$c += (int)(58 * $out[$j]);
$out[$j] = (int)($c % 256);
$c /= 256;
$c = (int)$c;
}
if($c != 0) Message(1, 'Invalid bitcoin wallet adress.');
}
$result = "";
foreach($out as $val) $result .= chr($val);
return $result;
}
$decoded = decodeBase58($address);
$d1 = hash("sha256", substr($decoded,0,21), true);
$d2 = hash("sha256", $d1, true);
if(substr_compare($decoded, $d2, 21, 4)) Message(1, 'Invalid bitcoin wallet adress.');
return true;
}
function decodeBase58($input) {
$alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
$out = array_fill(0, 25, 0);
for($i=0;$i
$c = $p;
for ($j = 25; $j--; ) {
$c += (int)(58 * $out[$j]);
$out[$j] = (int)($c % 256);
$c /= 256;
$c = (int)$c;
}
if($c != 0) Message(1, 'Invalid bitcoin wallet adress.');
}
$result = "";
foreach($out as $val) $result .= chr($val);
return $result;
}
Please help.
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