使用File.Encrypt加密文件,然后将其解密为内存流

Question

我需要实现一个简单的文件加密,然后在需要时将其解密到内存流.最简单的方法似乎是使用File.Encrypt执行此操作,但是是否可以将文件解密为内存流,而不是在将文件读取到内存流之前解密文件,从而将文件暴露一段时间？

如果File.Encrypt不是这种情况的最佳方式,你会推荐什么？

Answer 1

这是我编写的第一个加密代码 - 请注意，尽管这是了解正在发生的事情的一个很好的起点，但静态密码和静态盐不是一个好主意！（感谢您强调此 CodesInChaos）

您可以解密到任何您喜欢的流，包括直接解密到内存流......

FileInfo file = new FileInfo("SomeFile");
using (FileStream inFs = file.OpenRead())
{
    using (MemoryStream outMs = new MemoryStream())
    {
        encryption.Decrypt(inFs, outMs);                    

        BinaryFormatter bf = new BinaryFormatter();
        targetType target= bf.Deserialize(outMs) as targetType;
    }
}

其中加密是其中之一：

public class EncryptionHelper
{        
    static SymmetricAlgorithm encryption; 
    static string password = "password";
    static string salt = "this is my salt. There are many like it, but this one is mine.";

    static EncryptionHelper()
    {
        encryption = new RijndaelManaged();
        Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(password, Encoding.ASCII.GetBytes(salt));

        encryption.Key = key.GetBytes(encryption.KeySize / 8);
        encryption.IV = key.GetBytes(encryption.BlockSize / 8);
        encryption.Padding = PaddingMode.PKCS7;
    }

    public void Encrypt(Stream inStream, Stream OutStream)
    {
        ICryptoTransform encryptor = encryption.CreateEncryptor();
        inStream.Position = 0;
        CryptoStream encryptStream = new CryptoStream(OutStream, encryptor, CryptoStreamMode.Write);
        inStream.CopyTo(encryptStream);
        encryptStream.FlushFinalBlock();

    }


    public void Decrypt(Stream inStream, Stream OutStream)
    {
        ICryptoTransform encryptor = encryption.CreateDecryptor();
        inStream.Position = 0;
        CryptoStream encryptStream = new CryptoStream(inStream, encryptor, CryptoStreamMode.Read);
        encryptStream.CopyTo(OutStream);
        OutStream.Position = 0;  
    }
}