C＃PHP AES 256 CBC加密 [英] C# PHP AES 256 CBC Encryption

问题描述

你好，我正在尝试使用PHP和AES 256 CBC模式对服务器上的文件/字符串进行加密，
由于字符串以'ending0'结尾，我可以轻松地从其中删除填充AES的填充，但是我无法使用文件，因为其中一些文件包含空字节。在发送数据之前，我将其编码为base64字符串。

Hello I'm trying to encrypt files/strings on my server using PHP and AES 256 CBC mode, Because of strings ending with '\0' I can easly remove padding from them which AES adds, but with files I cannot because some of them contain null bytes. Before I send my data i encode it as base64 string.

这是我的C＃解密函数

 internal static byte[] __AES_DECRYPT(byte[] input, string _key, string _iv)
    {
        var myRijndael = new RijndaelManaged()
        {
            Padding = PaddingMode.Zeros,
            Mode = CipherMode.CBC,
            KeySize = 256,
            BlockSize = 256
        };
        byte[] key = Encoding.ASCII.GetBytes(_key);
        byte[] iv = Encoding.ASCII.GetBytes(_iv);
        var decryptor = myRijndael.CreateDecryptor(key, iv);
        var sEncrypted = input;
        var fromEncrypt = new byte[sEncrypted.Length];
        var msDecrypt = new MemoryStream(sEncrypted);
        var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read);
        csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length);
        return fromEncrypt;
    }

此功能也适用于字符串和字节。
我相信PHP加密功能对文件来说是错误的，但对字符串有效。

This function works fine for strings and bytes too. I believe PHP encrypt function is wrong for files but works for strings.

function encrypt($str)
{
  $key = 'keygoeshere';
  $iv =  "ivgoeshere";
  $str =mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $str, MCRYPT_MODE_CBC, $iv);
//$str = str_replace("\0","",$str);  this works for strings but not files.
  return base64_encode($str);
}

推荐答案

如果您不想要要更改为另一种填充形式，只需在文件内容的末尾附加一个1字节，然后在解密时删除所有尾随的null，然后删除附加的1个字节。您不会意外删除属于该文件的任何0个字节。

If you don't want to change to another form of padding, just append a single 1 byte to the end of the file contents, and on decryption, after removing any trailing nulls, then remove the appended 1 byte. You won't accidently remove any 0 bytes that belong to the file.

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