如何重新编码函数以使用FileStreams的String instad

时间:2019-05-07 07:26:19

标签: c# string encryption stream aes

我正在构建一个需要加密保存等的游戏。因此,我在开发一些功能来帮助我加密它们。但是,我目前拥有的唯一函数使用FileStreams进行输入和输出,但是我想使用字符串代替。这些功能在Files上可以正常工作,但是在从FileStreams到MemoryStreams到字符串交换时遇到了麻烦。 注意:我已删除了不相关的代码。 OurCodeWorld.GenerateRandomSalt() 100%可以正常工作,并通过FileStream加密进行了测试

完整代码:

Program.cs:

using System;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Threading;


namespace Encryption_test
{

    class Program
    {
        static public string encryptedExtension = ".aes";
        static public string decryptedExtension = ".decrypted";

        static void Main(string[] args)
        {
            string path = Environment.CurrentDirectory;
            Log($"Current path: {path}");
            string filePath = $"{path}/unencrypted.txt";
            string message =
@"Hello world!
This is my message. 1234";

            RunStackOverFlowString();

            //Sleep forever...zzz
            Thread.Sleep(10000);
            Console.WriteLine();

            float TicksToMs(long ticks)
            {
                return ticks / (float)Stopwatch.Frequency * 1000F;
            }

            void RunStackOverFlowString()
            {
                byte[] salt = OurCodeWorld.GenerateRandomSalt();
                int iterations = 1024;
                string password = "";
                string enc = StackOverflow.EncryptString(message, password, salt, iterations);
                Log($"Enc: {enc}");
                string dec = StackOverflow.DecryptString(enc, password, salt, iterations);
                Log($"Dec: {dec}");
            }
        private static void WriteFile(string path, string value)
        {
            FileStream _file = File.OpenWrite(path);
            byte[] info = new UTF8Encoding(true).GetBytes(value);
            _file.Write(info, 0, info.Length);
            _file.Close();
        }

        private static string ReadFile(string filePath, long length = long.MaxValue)
        {
            FileStream _file = File.OpenRead(filePath);
            if (length == long.MaxValue)
                length = _file.Length;

            byte[] b = new byte[length];
            UTF8Encoding temp = new UTF8Encoding(true);

            _file.Read(b, 0, b.Length);
            _file.Close();

            return temp.GetString(b);
        }

        private static void DeleteFile(string path)
        {
            File.Delete(path);
        }
        private static void CreateFile(string path)
        {
            if (File.Exists(path))
                DeleteFile(path);
            FileStream a = File.Open(path, FileMode.Create);
            a.Close();
        }
        static void Log(string message)
        {
            Console.WriteLine(message);
        }
    }
}

StackOverFlow.cs:

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

class StackOverflow
{

    // Rfc2898DeriveBytes constants:

    /// <summary>Decrypt a file.</summary>
    /// <remarks>NB: "Padding is invalid and cannot be removed." is the Universal CryptoServices error.  Make sure the password, salt and iterations are correct before getting nervous.</remarks>
    /// <param name="sourceFilename">The full path and name of the file to be decrypted.</param>
    /// <param name="destinationFilename">The full path and name of the file to be output.</param>
    /// <param name="password">The password for the decryption.</param>
    /// <param name="salt">The salt to be applied to the password.</param>
    /// <param name="iterations">The number of iterations Rfc2898DeriveBytes should use before generating the key and initialization vector for the decryption.</param>
    public static void DecryptFile(string sourceFilename, string destinationFilename, string password, byte[] salt, int iterations)
    {
        AesManaged aes = new AesManaged();
        aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
        aes.KeySize = aes.LegalKeySizes[0].MaxSize;
        // NB: Rfc2898DeriveBytes initialization and subsequent calls to   GetBytes   must be eactly the same, including order, on both the encryption and decryption sides.
        Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, salt, iterations);
        aes.Key = key.GetBytes(aes.KeySize / 8);
        aes.IV = key.GetBytes(aes.BlockSize / 8);
        aes.Mode = CipherMode.CBC;
        ICryptoTransform transform = aes.CreateDecryptor(aes.Key, aes.IV);

        using (FileStream destination = new FileStream(destinationFilename, FileMode.Create, FileAccess.Write, FileShare.None))
        {
            using (CryptoStream cryptoStream = new CryptoStream(destination, transform, CryptoStreamMode.Write))
            {
                try
                {
                    using (FileStream source = new FileStream(sourceFilename, FileMode.Open, FileAccess.Read, FileShare.Read))
                    {
                        source.CopyTo(cryptoStream);
                    }
                }
                catch (CryptographicException exception)
                {
                    if (exception.Message == "Padding is invalid and cannot be removed.")
                        throw new ApplicationException("Universal Microsoft Cryptographic Exception (Not to be believed!)", exception);
                    else
                        throw;
                }
            }
        }
    }

    /// <summary>Encrypt a file.</summary>
    /// <param name="sourceFilename">The full path and name of the file to be encrypted.</param>
    /// <param name="destinationFilename">The full path and name of the file to be output.</param>
    /// <param name="password">The password for the encryption.</param>
    /// <param name="salt">The salt to be applied to the password.</param>
    /// <param name="iterations">The number of iterations Rfc2898DeriveBytes should use before generating the key and initialization vector for the decryption.</param>
    public static void EncryptFile(string sourceFilename, string destinationFilename, string password, byte[] salt, int iterations)
    {
        AesManaged aes = new AesManaged();
        aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
        aes.KeySize = aes.LegalKeySizes[0].MaxSize;
        // NB: Rfc2898DeriveBytes initialization and subsequent calls to   GetBytes   must be eactly the same, including order, on both the encryption and decryption sides.
        Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, salt, iterations);
        aes.Key = key.GetBytes(aes.KeySize / 8);
        aes.IV = key.GetBytes(aes.BlockSize / 8);
        aes.Mode = CipherMode.CBC;
        ICryptoTransform transform = aes.CreateEncryptor(aes.Key, aes.IV);

        using (FileStream destination = new FileStream(destinationFilename, FileMode.Create, FileAccess.Write, FileShare.None))
        {
            using (CryptoStream cryptoStream = new CryptoStream(destination, transform, CryptoStreamMode.Write))
            {
                using (FileStream source = new FileStream(sourceFilename, FileMode.Open, FileAccess.Read, FileShare.Read))
                {
                    source.CopyTo(cryptoStream);
                }
            }
        }
    }

    //THIS IS MY CODE
    public static string EncryptString(string inputString, string password, byte[] salt, int iterations)
    {
        AesManaged aes = new AesManaged();
        aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
        aes.KeySize = aes.LegalKeySizes[0].MaxSize;
        // NB: Rfc2898DeriveBytes initialization and subsequent calls to   GetBytes   must be eactly the same, including order, on both the encryption and decryption sides.
        Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, salt, iterations);
        aes.Key = key.GetBytes(aes.KeySize / 8);
        aes.IV = key.GetBytes(aes.BlockSize / 8);
        aes.Mode = CipherMode.CBC;
        ICryptoTransform transform = aes.CreateEncryptor(aes.Key, aes.IV);

        var source = StringToStream(inputString);
        var output = new MemoryStream();

        CryptoStream cryptoStream = new CryptoStream(output, transform, CryptoStreamMode.Write);
        source.CopyTo(cryptoStream);
        return StreamToString(output);
    }

    public static string DecryptString(string inputString, string password, byte[] salt, int iterations)
    {
        AesManaged aes = new AesManaged();
        aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
        aes.KeySize = aes.LegalKeySizes[0].MaxSize;
        // NB: Rfc2898DeriveBytes initialization and subsequent calls to   GetBytes   must be eactly the same, including order, on both the encryption and decryption sides.
        Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, salt, iterations);
        aes.Key = key.GetBytes(aes.KeySize / 8);
        aes.IV = key.GetBytes(aes.BlockSize / 8);
        aes.Mode = CipherMode.CBC;
        ICryptoTransform transform = aes.CreateDecryptor(aes.Key, aes.IV);

        var source = StringToStream(inputString);
        var output = new MemoryStream();

        CryptoStream cryptoStream = new CryptoStream(output, transform, CryptoStreamMode.Write);
        source.CopyTo(cryptoStream);
        return StreamToString(output);
    }


    public static Stream StringToStream(string s)
    {
        var stream = new MemoryStream();
        var writer = new StreamWriter(stream);
        writer.Write(s);
        writer.Flush();
        stream.Position = 0;
        return stream;
    }
    public static string StreamToString(Stream s)
    {
        s.Position = 0;
        byte[] buffer = new byte[s.Length];
        s.Read(buffer, 0, (int)s.Length);
        return Encoding.Default.GetString(buffer);
    }
}

我已经测试了StreamToStringStringToStream方法,它们可以正常工作。当我运行DecryptString时,没有输出,该函数返回乱码,通常看起来与此Dec: ?K??? ?@?????n?l?r????T?

相似

2 个答案:

答案 0 :(得分:0)

使用和Encoding完成字符串和二进制数据之间的转换。编码确定如何将字符转换为二进制数据。常见的编码是Unicode,UTF8或ASCII。如果您希望获得可预测的结果,则需要为两种转换使用特定的编码。

StringToStream中使用Encoding.Default时,您根本没有指定编码。 StreamToString无法提供可预测的结果,因为它使用当前的代码页(如果您在Windows系统上运行)。因此,您不能确定两种方法都使用相同的编码。

解决方案是在两端提供相同的编码:

Encoding.Default

答案 1 :(得分:0)

我测试了代码。有两个问题:

  1. 您获取加密的字节,然后使用编码将其转换为字符串。通常,此过程将失败,因为您不能获取任意字节并将其转换为字符串。字节和字符串之间的映射不是1:1。可能,您完全不应该在这里使用字符串。而是将数据保留为字节格式,然后将这些字节写入文件。方法签名应类似于byte[] Encrypt(byte[] input, ...)。加密代码无需在字符串之间进行转换。
  2. EncryptString必须使用FlushFinalBlock刷新加密流。如果不这样做,最后的数据将丢失。