为什么mcrypt_encrypt（）将二进制字符放在字符串的末尾？ [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>\n";

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

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

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



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;
}

?>

输出是：

The output is:

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

输出是成功解密，但28个二进制字符被添加到最后，这可以很容易地在Firefox中看到，当查看HTML源代码
字符串长度为32也表明了这一点任何想法？

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 0 这就是为什么你看到额外的数据。

The returned string is padded out to fill n * blocksize bytes using the null character \0 so that is why you are seeing the extra data.

如果你运行 $ card_nbr_decrypted = rtrim（$ card_nbr_decrypted ，\0）; 它应该返回实际数据。

If you run $card_nbr_decrypted= rtrim($card_nbr_decrypted, "\0"); it should return the actual data.

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