<?php
$data = "Test Data\x00\x00";
echo strlen($data)."\n";
 
$key = "mykey";
$blocksize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);
 
// PKCS7 Padding
$pad = $blocksize - (strlen($data) % $blocksize);
$data .= str_repeat(chr($pad), $pad);
 
$encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, MD5($key, true), $data, MCRYPT_MODE_ECB);
echo strlen($encrypted)."\n";
 
$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, MD5($key, true), $encrypted, MCRYPT_MODE_ECB);
echo strlen($decrypted)."\n";
 
// PKCS7 Padding
$strPad = ord($decrypted[strlen($decrypted)-1]);
$newData = substr($decrypted, 0, -$strPad);
 
echo strlen($newData)."\n";

PD9waHAKJGRhdGEgPSAiVGVzdCBEYXRhXHgwMFx4MDAiOwplY2hvIHN0cmxlbigkZGF0YSkuIlxuIjsKCiRrZXkgPSAibXlrZXkiOwokYmxvY2tzaXplID0gbWNyeXB0X2dldF9ibG9ja19zaXplKE1DUllQVF9SSUpOREFFTF8xMjgsIE1DUllQVF9NT0RFX0VDQik7CgovLyBQS0NTNyBQYWRkaW5nCiRwYWQgPSAkYmxvY2tzaXplIC0gKHN0cmxlbigkZGF0YSkgJSAkYmxvY2tzaXplKTsKJGRhdGEgLj0gc3RyX3JlcGVhdChjaHIoJHBhZCksICRwYWQpOwoKJGVuY3J5cHRlZCA9IG1jcnlwdF9lbmNyeXB0KE1DUllQVF9SSUpOREFFTF8xMjgsIE1ENSgka2V5LCB0cnVlKSwgJGRhdGEsIE1DUllQVF9NT0RFX0VDQik7CmVjaG8gc3RybGVuKCRlbmNyeXB0ZWQpLiJcbiI7CgokZGVjcnlwdGVkID0gbWNyeXB0X2RlY3J5cHQoTUNSWVBUX1JJSk5EQUVMXzEyOCwgTUQ1KCRrZXksIHRydWUpLCAkZW5jcnlwdGVkLCBNQ1JZUFRfTU9ERV9FQ0IpOwplY2hvIHN0cmxlbigkZGVjcnlwdGVkKS4iXG4iOwoKLy8gUEtDUzcgUGFkZGluZwokc3RyUGFkID0gb3JkKCRkZWNyeXB0ZWRbc3RybGVuKCRkZWNyeXB0ZWQpLTFdKTsKJG5ld0RhdGEgPSBzdWJzdHIoJGRlY3J5cHRlZCwgMCwgLSRzdHJQYWQpOwoKZWNobyBzdHJsZW4oJG5ld0RhdGEpLiJcbiI7