为什么 mcrypt_encrypt() 将二进制字符放在我的字符串末尾? [英] Why is mcrypt_encrypt() putting binary characters at the end of my string?

问题描述

这是一个加密和解密数据的 PHP 演示脚本:

Here is a PHP demo script that encrypts and decrypts data:

<?

$encryptionkey = 'h8y2p9d1';

$card_nbr = "1234";
echo "original card_nbr: $card_nbr <br>
";

$card_nbr_encrypted=encrypt_data($card_nbr);
echo "card_nbr_encrypted: $card_nbr_encrypted <br>
";

$card_nbr_decrypted=decrypt_data($card_nbr_encrypted);
echo "card_nbr_decrypted: $card_nbr_decrypted <br>
";

$len=strlen($card_nbr_decrypted);
echo "length: $len <br>
";



function encrypt_data($text){
  global $encryptionkey;
  $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
  $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
  $encrypted_text = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $encryptionkey, $text, MCRYPT_MODE_ECB, $iv);
  return $encrypted_text;
}

function decrypt_data($text){
  global $encryptionkey;
  $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
  $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
  $decrypted_text = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $encryptionkey, $text, MCRYPT_MODE_ECB, $iv);
  return $decrypted_text;
}

?>

输出为:

original card_nbr: 1234
card_nbr_encrypted: vY¨(Z$<§G3-žÃ-Éù3Ý2Ê×rz¨VÛ
card_nbr_decrypted: 1234  (and 28 binary characters)
length: 32 

输出成功解密，但最后添加了 28 个二进制字符.在 Firefox 中查看 HTML 源代码时最容易看到这一点.32 的字符串长度也证明了这一点.有什么想法吗?

The output is successfully decrypted, but 28 binary characters are added to the end. This can most easily be seen in Firefox, when viewing HTML source. The string length of 32 also demonstrates this. Any ideas?

推荐答案

使用空字符 填充返回的字符串以填充 n * blocksize 个字节，因此这就是您看到额外数据的原因.

The returned string is padded out to fill n * blocksize bytes using the null character so that is why you are seeing the extra data.

如果你运行 $card_nbr_decrypted= rtrim($card_nbr_decrypted, ""); 它应该返回实际数据.

If you run $card_nbr_decrypted= rtrim($card_nbr_decrypted, ""); it should return the actual data.

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