RC2解密问题(数据丢失) [英] RC2 Decryption problem (lost of data)

问题描述

private void button1_Click_1(object sender, EventArgs e)
{
    string enc = rc("some string", "some key", true);
    MessageBox.Show(enc);
    string dec = rc(enc, "some key", false);
    MessageBox.Show(dec);
}

private string rc(string text, string key, bool enc)
{

    string plainText = text;
    byte[] buffer = ASCIIEncoding.ASCII.GetBytes(plainText);
    RC2CryptoServiceProvider rc2 = new RC2CryptoServiceProvider();
    rc2.Key = ASCIIEncoding.ASCII.GetBytes(key);
    rc2.GenerateIV();
    if (enc)
    {
        string encryptedString = Convert.ToBase64String(
        rc2.CreateEncryptor().TransformFinalBlock(
        buffer, 0, buffer.Length));
        return encryptedString;
    }
    else
    {
        buffer = Convert.FromBase64String(text);
        byte[] b_dec = rc2.CreateDecryptor().TransformFinalBlock(buffer, 0, buffer.Length);
        string decryptedString = ASCIIEncoding.ASCII.GetString(b_dec);
        return decryptedString;
    }
}

为什么:
-每次加密的字符串都不相同
-解密的字符串是错误的("ing"之前的所有字符都不可读)
?
请帮助.

Why:
- encrypted string is different each time
- decrypted string is wrong(all characters before ''ing'' are unreadable)
?
Please, help.

推荐答案

rc2.GenerateIV() 需要替换为以下固定内容:
rc2.IV = new byte[] { 23, 10, 99, 73, 44, 69, 35, 80 };

rc2.GenerateIV() was needed to replace with something fixed as this:
rc2.IV = new byte[] { 23, 10, 99, 73, 44, 69, 35, 80 };

我对RC2不太了解，但是您确定它不应该每次都生成一个新的加密字符串吗?可能不是，但是我以前听说过.

I don''t know much about RC2, but are you sure that it is not supposed to make a new encrypted string everytime? Probably not, but I''ve heard of it before.

问题是下面的行

The problem is that the following line

halabella写道:

halabella wrote:

rc2.GenerateIV();

rc2.GenerateIV();

每次调用都会生成一个 new 随机向量.

快速修复:

添加以下类成员变量:

every time is called generates a new random vector.

Quick fix:

Add the following class member variable:

byte [] iv =null;

然后以这种方式修改功能:

then modify the function this way:

private string rc(string text, string key, bool enc)
{
    string plainText = text;
    byte[] buffer = ASCIIEncoding.ASCII.GetBytes(plainText);
    RC2CryptoServiceProvider rc2 = new RC2CryptoServiceProvider();
    rc2.Key = ASCIIEncoding.ASCII.GetBytes(key);
    if (iv == null)
    {
        rc2.GenerateIV();
        iv = rc2.IV;
    }
    else
    {
        rc2.IV = iv;
    }
    if (enc)
    {
        string encryptedString = Convert.ToBase64String(
        rc2.CreateEncryptor().TransformFinalBlock(
        buffer, 0, buffer.Length));
        return encryptedString;
    }
    else
    {
        buffer = Convert.FromBase64String(text);
        byte[] b_dec = rc2.CreateDecryptor().TransformFinalBlock(buffer, 0, buffer.Length);
        string decryptedString = ASCIIEncoding.ASCII.GetString(b_dec);
        return decryptedString;
    }
}

当然，根据您的需求，您可能会发现更优雅的灵魂

Of course you may find a more elegant soultion depending on your needs

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