问题
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.
Here is my C# decrypt function
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;
}
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);
}
回答1:
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.
来源：https://stackoverflow.com/questions/24372308/c-sharp-php-aes-256-cbc-encryption