Aes加密字节数组为空

Question

我正在实现加密/解密方法，如本示例所示。问题是

EncryptString

方法中的字节数组为空；因此，结果字符串也是空的。怎么解决问题？

using System.Security.Cryptography;
using System.Text;

Crypto crypto = new();

string test = "test";

string encrypted = crypto.EncryptString(test);
string decrypted = crypto.DecryptString(encrypted);

Console.WriteLine($"{test}\n{encrypted}\n{decrypted}");
Console.ReadKey();

class Crypto
{
    byte[] key = Encoding.UTF8.GetBytes("01234567890123456789012345678901");
    byte[] iv = new byte[16];

    public string EncryptString(string plainText)
    {
        using Aes aes = Aes.Create();
        aes.Key = key;
        aes.IV = iv;

        ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);

        using MemoryStream memoryStream = new();
        using CryptoStream cryptoStream = new(memoryStream, encryptor, CryptoStreamMode.Write);
        using StreamWriter streamWriter = new(cryptoStream);

        streamWriter.Write(plainText);

        // Array is empty here
        byte[] array = memoryStream.ToArray();

        return Encoding.UTF8.GetString(array);
    }

    public string DecryptString(string cipherText)
    {
        using Aes aes = Aes.Create();
        aes.Key = key;
        aes.IV = iv;

        ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);

        using MemoryStream memoryStream = new(Encoding.UTF8.GetBytes(cipherText));
        using CryptoStream cryptoStream = new(memoryStream, decryptor, CryptoStreamMode.Read);
        using StreamReader streamReader = new(cryptoStream);

        string decrypted = streamReader.ReadToEnd();

        return decrypted;
    }
}

Answer 1

请注意，在您尝试复制的代码中，它们具有：

using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
      //Write all data to the stream.
      swEncrypt.Write(plainText);
}
encrypted = msEncrypt.ToArray();

在调用

StreamWriter

 之前，

msEncrypt.ToArray()

已关闭（处置）。在您的代码中，它是不一样的 -

StreamWriter

直到作用域结束时才关闭（因为使用语句），因此当使用

memoryStream.ToArray()

时 - 尚未向该流写入任何内容。简单修复：

using MemoryStream memoryStream = new();
using CryptoStream cryptoStream = new(memoryStream, encryptor, CryptoStreamMode.Write);
using StreamWriter streamWriter = new(cryptoStream);

streamWriter.Write(plainText);
streamWriter.Close();
byte[] array = memoryStream.ToArray();

或者更好 - 只是在不必要的地方不要使用范围大小的

using

语句。

此外，加密结果请勿使用 UTF8 编码。加密的结果是二进制数据，而不是文本。如果您必须将其存储为字符串 - 使用诸如 Base64 编码之类的编码，而不是诸如 UTF8 之类的文本编码。