$compressed_public_key = "12CLR6mkJMqhAoyuAsbjmgo6RuVc99dM76";
$public_key_sha256 = hash('sha256', $compressed_public_key);
$ripemd160_of_sha256 = hash('ripemd160',$public_key_sha256);
$redeemScript = "0014".$ripemd160_of_sha256;
$sha256_of_redeemScript = hash('sha256', $redeemScript);
$ripemd160_of_redeemScript = hash('ripemd160',$sha256_of_redeemScript);
$segwitAddress = base58_encode_with_prefix_and_checksum(0x05, $ripemd160_of_redeemScript);