C＃中的AES加密功能有什么问题？ 为什么返回零长度数据？

Question

public static byte[] AES_Encrypt(byte[] data, string[] aes_key)
{
    var aes = new RijndaelManaged();
    aes.KeySize = 256;
    aes.BlockSize = 256;
    aes.Padding = PaddingMode.PKCS7;

    aes.Key = Encoding.Default.GetBytes(aes_key[0]);
    aes.IV = Encoding.Default.GetBytes(aes_key[1]);

    var encrypt = aes.CreateEncryptor(aes.Key, aes.IV);

    MemoryStream ms = new MemoryStream();
    CryptoStream cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write);

    cs.Write(data, 0, data.Length);

    return ms.ToArray();
}

public static byte[] AES_Decrypt(byte[] data, string[] aes_key)
{
    RijndaelManaged aes = new RijndaelManaged();
    aes.KeySize = 256;
    aes.BlockSize = 256;
    aes.Mode = CipherMode.CBC;
    aes.Padding = PaddingMode.PKCS7;

    aes.Key = Encoding.Default.GetBytes(aes_key[0]);
    aes.IV = Encoding.Default.GetBytes(aes_key[1]);

    var decrypt = aes.CreateDecryptor();

    MemoryStream ms = new MemoryStream();
    CryptoStream cs = new CryptoStream(ms, decrypt, CryptoStreamMode.Write);

    cs.Write(data, 0, data.Length);

    return ms.ToArray();
}

Somewhere in code:

string key = "788b0adbcf8b9211282fe613b18630d2";
string iv = "7fbb16b806fcc24396653b3218552d39";
byte[] test_byte = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
byte[] enc_byte = AES_Encrypt(test_byte, new string[] { key, iv }); //getting zero array
byte[] dec_byte = AES_Decrypt(enc_byte, new string[] { key, iv });

Answer 1

You need using blocks around your streams to ensure they are closed and flushed. Try this:

public static byte[] AES_Encrypt(byte[] data, string[] aes_key)
{
    var aes = new RijndaelManaged();
    aes.KeySize = 256;
    aes.BlockSize = 256;
    aes.Padding = PaddingMode.PKCS7;

    aes.Key = Encoding.Default.GetBytes(aes_key[0]);
    aes.IV = Encoding.Default.GetBytes(aes_key[1]);

    var encrypt = aes.CreateEncryptor(aes.Key, aes.IV);

    using(MemoryStream ms = new MemoryStream())
    {
      using(CryptoStream cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write))
        cs.Write(data, 0, data.Length);

      return ms.ToArray();
    }
}

public static byte[] AES_Decrypt(byte[] data, string[] aes_key)
{
    RijndaelManaged aes = new RijndaelManaged();
    aes.KeySize = 256;
    aes.BlockSize = 256;
    aes.Mode = CipherMode.CBC;
    aes.Padding = PaddingMode.PKCS7;

    aes.Key = Encoding.Default.GetBytes(aes_key[0]);
    aes.IV = Encoding.Default.GetBytes(aes_key[1]);

    var decrypt = aes.CreateDecryptor();

    using(MemoryStream ms = new MemoryStream())
    {
      using(CryptoStream cs = new CryptoStream(ms, decrypt, CryptoStreamMode.Write))
        cs.Write(data, 0, data.Length);

      return ms.ToArray();
    }
}

Answer 2

If you use using statements with your CryptoStream s , it will flush and close so that it actually updates your MemoryStream s. The documentation for CryptoStream documents this behavior: you should always Close when you're done writing to it. Here's how that looks (very similar for encrypt and decrypt):

using (CryptoStream cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write))
    cs.Write(data, 0, data.Length);
return ms.ToArray();

Answer 3

在将流转换为数组之前，请调用FlushFinalBlock 。