Question

我坚持使用加密方法。我对加密或字节数组知之甚少，所以我很难解决这个问题。

这是我的代码：

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但每当我传递一个字符串为public static class EncryptDecrypt { private static byte[] key = { }; private static string sEncryptionKey = "B@|@j!"; private static byte[] IV = {0x12, 0x34, 0x56, 0x78, 0x90, 0xab}; public static string Encrypt(string stringToEncrypt) { string returnstring = ""; try { key = System.Text.Encoding.UTF8.GetBytes(sEncryptionKey); DESCryptoServiceProvider des = new DESCryptoServiceProvider(); byte[] inputByteArray = Encoding.UTF8.GetBytes(stringToEncrypt); System.IO.MemoryStream ms = new System.IO.MemoryStream(); CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(key, IV), CryptoStreamMode.Write); cs.Write(inputByteArray, 0, inputByteArray.Length); cs.FlushFinalBlock(); returnstring = Convert.ToBase64String(ms.ToArray()); //URL Encryption Avoid Reserved Characters returnstring = returnstring.Replace("/", "-2F-"); returnstring = returnstring.Replace("!", "-21-"); returnstring = returnstring.Replace("#", "-23-"); returnstring = returnstring.Replace("$", "-24-"); returnstring = returnstring.Replace("&", "-26-"); returnstring = returnstring.Replace("'", "-27-"); returnstring = returnstring.Replace("(", "-28-"); returnstring = returnstring.Replace(")", "-29-"); returnstring = returnstring.Replace("*", "-2A-"); returnstring = returnstring.Replace("+", "-2B-"); returnstring = returnstring.Replace(",", "-2C-"); returnstring = returnstring.Replace(":", "-3A-"); returnstring = returnstring.Replace(";", "-3B-"); returnstring = returnstring.Replace("=", "-3D-"); returnstring = returnstring.Replace("?", "-3F-"); returnstring = returnstring.Replace("@", "-40-"); returnstring = returnstring.Replace("[", "-5B-"); returnstring = returnstring.Replace("]", "-5D-"); return returnstring; } catch (Exception e) { return e.Message; } } }时它会提供错误指定的密钥不是此算法的有效大小。如何解决这个问题，如何通过这种方法加密任何字符串（主要是1-8个字符）？

Answer 1

DES算法需要64位（8字节）密钥。您的sEncryptionKey长度为6个字符，这就是“指定密钥不是有效大小”错误的原因。

DES使用64位密钥，这些密钥不应该是像SomePass这样的人性化密码。它们应该是二进制密钥，涵盖了64位密钥的所有可能变化（2 ^ 64种不同的组合）。否则，您的加密将比DES标准暗示的要弱得多。

这就是为什么在使用System.Security.Cryptography中的对称加密算法时，您应该将您的秘密视为将用于加密的最终密钥，而不是作为生成加密密钥的密码。您可以通过使用passprase和salt（可以随机生成但也应在解密期间使用）构造System.Security.Cryptography.Rfc2898DeriveBytes的实例来执行此生成。

您的代码的另一个问题是您正在使用长度为6个字节的初始化向量（IV）。它也应该是8字节长度，你应该为每个加密使用随机初始化向量。您可以通过调用DESCryptoServiceProvider.GenerateIV()方法并访问DESCryptoServiceProvider.IV属性来生成IV。

最后的说明。由于您将returnstring转换为Base64，因此无需替换所有这些特殊字符，例如'＆amp;'和'$'。 Base64字符集由数字，数字和'+'，'/'，'='符号组成。你可以只替换这3个字符。

所以这里是根据以上评论编辑你的代码：

public static class EncryptDecrypt
{
    private static string sEncryptionPassphrase = "B@|@j!";

    public static string Encrypt(string stringToEncrypt)
    {
        try
        {
            string returnstring;
            var salt = GenerateSalt();
            using (var keyBytes = new Rfc2898DeriveBytes(sEncryptionPassphrase, salt))
            {
                var key = keyBytes.GetBytes(8);

                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                des.GenerateIV();
                byte[] inputByteArray = Encoding.UTF8.GetBytes(stringToEncrypt);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(key, des.IV), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                returnstring = Convert.ToBase64String(ms.ToArray());
            }

            //URL Encryption Avoid Reserved Characters
            returnstring = returnstring.Replace("/", "-2F-");
            returnstring = returnstring.Replace("+", "-2B-");
            returnstring = returnstring.Replace("=", "-3D-");

            return returnstring;
        }
        catch (Exception e)
        {
            return e.Message;
        }
    }

    private static byte[] GenerateSalt()
    {
        var randomBytes = new byte[8];
        using (var rngCsp = new RNGCryptoServiceProvider())
        {
            rngCsp.GetBytes(randomBytes);
        }
        return randomBytes;
    }
}

错误：指定的密钥不是此算法的有效大小

1 个答案: