C# 在写入磁盘之前加密序列化文件

Question

假设我的程序有一个名为“customer”的类，并且该客户类是可序列化的，因此我可以读取它并将其写入磁盘。客户类包含我想要加密的敏感信息，我知道我可以保证文件安全的唯一方法是:

1-Serialize the file to disk

2-Reopen and load the file

3-Encrypt the file

4-Rewrite file to disk

这可行，但存在文件在未加密状态下可能被拦截的风险，而且效率非常低。

相反，我想:

1-Create file in memory

2-Encrypt file in memory

3-Write encrypted file to disk

这可能吗？如果是怎么办？提前致谢。

Answer 1

您可以在将类序列化为文件的同时使用 CryptoStream 进行加密:

byte[] key = { 1, 2, 3, 4, 5, 6, 7, 8 }; // Where to store these keys is the tricky part, 
    // you may need to obfuscate them or get the user to input a password each time
byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };
string path = @"C:\path\to.file";

DESCryptoServiceProvider des = new DESCryptoServiceProvider();

// Encryption
using (var fs = new FileStream(path, FileMode.Create, FileAccess.Write))
using (var cryptoStream = new CryptoStream(fs, des.CreateEncryptor(key, iv), CryptoStreamMode.Write))
{
    BinaryFormatter formatter = new BinaryFormatter();

    // This is where you serialize the class
    formatter.Serialize(cryptoStream, customClass);
}

// Decryption
using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read))
using (var cryptoStream = new CryptoStream(fs, des.CreateDecryptor(key, iv), CryptoStreamMode.Read))
{
    BinaryFormatter formatter = new BinaryFormatter();

    // This is where you deserialize the class
    CustomClass deserialized = (CustomClass)formatter.Deserialize(cryptoStream);
}