RijndaelManaged，对于特定的输入，两组不同的密钥都可以解密

Question

加密和解密方法来自Microsoft文档。

我有两套不同的钥匙。当我使用key1加密并使用key2解密时，我预计会抛出CryptographicException，但它实际上是一个乱码文本。

class Program
{
private static readonly byte[] key1 = new byte[] { 0xAC, 0x1F, 0xC4, 0x8F, 0x4C, 0x79, 0x10, 0xA1, 0x11, 0xD6, 0x7D, 0x24, 0xCE, 0x73, 0x6C, 0xE7, 0x8E, 0xD2, 0x97, 0xC2, 0x90, 0x21, 0x27, 0xE9, 0x68, 0x3F, 0x50, 0x5B, 0x92, 0x40, 0x6D, 0xC9 };
private static readonly byte[] iv1 = new byte[] { 0xF8, 0x14, 0x77, 0xFE, 0xFC, 0x84, 0x8E, 0x66, 0x82, 0x58, 0x01, 0x6D, 0x43, 0x12, 0xD8, 0x6F };
private static readonly byte[] key2 = new byte[] { 0x9D, 0xD8, 0x77, 0x5D, 0xA4, 0x60, 0x14, 0xFE, 0x89, 0xB6, 0xAF, 0x40, 0x2B, 0xFE, 0xE5, 0xD2, 0x0B, 0xDF, 0x55, 0x26, 0x37, 0x77, 0x6F, 0x21, 0x9A, 0x27, 0xB4, 0xD7, 0x08, 0xEA, 0xC6, 0xB9 };
private static readonly byte[] iv2 = new byte[] { 0x4D, 0x24, 0x83, 0x94, 0x3D, 0x29, 0x86, 0x7F, 0x40, 0x3A, 0x4F, 0x87, 0x37, 0x0B, 0x11, 0x8E };
static void Main(string[] args)
{
var ticks = 637375909118731913;
string original = JsonConvert.SerializeObject(new DateTime(ticks, DateTimeKind.Utc));
using (RijndaelManaged myRijndael = new RijndaelManaged())
{
byte[] encrypted = EncryptStringToBytes(original, key1, iv1);
Console.WriteLine("Original:   {0}", original);
string roundtrip = DecryptStringFromBytes(encrypted, key1, iv1);
Console.WriteLine("Round Trip: {0}", roundtrip);
try
{
string roundtrip2 = DecryptStringFromBytes(encrypted, key2, iv2);
Console.WriteLine("Round Trip2: {0}", roundtrip2);
}
catch (CryptographicException e)
{
Console.WriteLine("Round Trip2: Unable to decrypt, expected.");
}
}
}
static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV)
{
byte[] encrypted;
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
swEncrypt.Write(plainText);
}
encrypted = msEncrypt.ToArray();
}
}
}
return encrypted;
}
static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV)
{
string plaintext = null;
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
using (MemoryStream msDecrypt = new MemoryStream(cipherText))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
plaintext = srDecrypt.ReadToEnd();
}
}
}
}
return plaintext;
}
}

输出：

Original:   "2020-10-06T14:21:51.8731913Z"
Round Trip: "2020-10-06T14:21:51.8731913Z"
Round Trip2: 7cB?]?wV???DFI?|hgY?Q?&x

预期：

Original:   "2020-10-06T14:21:51.8731913Z"
Round Trip: "2020-10-06T14:21:51.8731913Z"
Round Trip2: Unable to decrypt, expected.

如果我更改记号值，这种情况只会在特定输入中发生

var ticks = 637375909118731914;

一切如预期。

我犯了什么错误？

注意：

还有许多其他输入值会导致这种情况，这会在我的应用程序中导致意外错误。

Answer 1

我的解决方案是确定字符串是否为json格式。

if(IsJson(roundtrip))
{
Console.WriteLine("Round Trip: {0}", roundtrip);
}
else
{
Console.WriteLine("Round Trip: Unable to decrypt.");
}