PHP - Validate Multisig Bitcoin Wallet Address with Leading 2 or 3

Question

I have used this function for validating the bitcoin wallet address to see if it's a bitcoin address. However, it's not working with the address that starts with "3" (multi-sig). For example, 3EktnHQD7RiAE6uzMj2ZifT9YgRrkSgzQX.

Can anyone help me with that function to make it work so that it can validate all major forms of bitcoin wallet addresses?

Answer 1

 The answer to your question is given below: 

function validate($address){ $decoded = decodeBase58($address); $d1 = hash("sha256", substr($decoded,0,21), true); $d2 = hash("sha256", $d1, true); if(substr_compare($decoded, $d2, 21, 4)){ throw new \Exception("bad digest"); } return true; } function decodeBase58($input) { $alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"; $out = array_fill(0, 25, 0); for($i=0;$i<strlen($input);$i++){ if(($p=strpos($alphabet, $input[$i]))===false){ throw new \Exception("invalid character found"); } $c = $p; for ($j = 25; $j--; ) { $c += (int)(58 * $out[$j]); $out[$j] = (int)($c % 256); $c /= 256; $c = (int)$c; } if($c != 0){ throw new \Exception("address too long"); } } $result = ""; foreach($out as $val){ $result .= chr($val); } return $result; } function main () { $s = array( "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9", "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9", "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I", ); foreach($s as $btc){ $message = "OK"; try{ validate($btc); }catch(\Exception $e){ $message = $e->getMessage(); } echo "$btc: $message\n"; } } main();

Hope this clarifies your doubt. 

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