Porady: stosowanie ochrony danych

Uwaga

Ten artykuł dotyczy systemu Windows.

Aby uzyskać informacje o ASP.NET Core, zobacz ASP.NET Core Data Protection.

Platforma .NET zapewnia dostęp do interfejsu API ochrony danych (DPAPI), który umożliwia szyfrowanie danych przy użyciu informacji z bieżącego konta użytkownika lub komputera. W przypadku korzystania z interfejsu DPAPI można złagodzić trudny problem jawnego generowania i przechowywania klucza kryptograficznego.

ProtectedData Użyj klasy , aby zaszyfrować kopię tablicy bajtów. Można określić, że dane zaszyfrowane przy użyciu bieżącego konta użytkownika można odszyfrować tylko za pomocą tego samego konta użytkownika lub określić, że dane zaszyfrowane przy użyciu bieżącego konta użytkownika mogą być odszyfrowywane przez dowolne konto na komputerze. DataProtectionScope Zobacz wyliczenie, aby uzyskać szczegółowy opis ProtectedData opcji.

Szyfrowanie danych do pliku lub strumienia przy użyciu ochrony danych

  1. Utwórz losową entropię.

  2. Wywołaj metodę statyczną Protect podczas przekazywania tablicy bajtów do szyfrowania, entropii i zakresu ochrony danych.

  3. Zapisz zaszyfrowane dane w pliku lub strumieniu.

Aby odszyfrować dane z pliku lub strumienia przy użyciu ochrony danych

  1. Odczytywanie zaszyfrowanych danych z pliku lub strumienia.

  2. Wywołaj metodę statyczną Unprotect podczas przekazywania tablicy bajtów do odszyfrowywania i zakresu ochrony danych.

Przykład

Poniższy przykład kodu przedstawia dwie formy szyfrowania i odszyfrowywania. Najpierw przykładowy kod szyfruje, a następnie odszyfrowuje tablicę bajtów w pamięci. Następnie przykładowy kod szyfruje kopię tablicy bajtów, zapisuje ją w pliku, ładuje dane z powrotem z pliku, a następnie odszyfrowuje dane. W przykładzie są wyświetlane oryginalne dane, zaszyfrowane dane i odszyfrowane dane.

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

public class MemoryProtectionSample
{
    public static void Main() => Run();

    public static void Run()
    {
        try
        {
            ///////////////////////////////
            //
            // Memory Encryption - ProtectedMemory
            //
            ///////////////////////////////

            // Create the original data to be encrypted (The data length should be a multiple of 16).
            byte[] toEncrypt = UnicodeEncoding.ASCII.GetBytes("ThisIsSomeData16");

            Console.WriteLine($"Original data: {UnicodeEncoding.ASCII.GetString(toEncrypt)}");
            Console.WriteLine("Encrypting...");

            // Encrypt the data in memory.
            EncryptInMemoryData(toEncrypt, MemoryProtectionScope.SameLogon);

            Console.WriteLine($"Encrypted data: {UnicodeEncoding.ASCII.GetString(toEncrypt)}");
            Console.WriteLine("Decrypting...");

            // Decrypt the data in memory.
            DecryptInMemoryData(toEncrypt, MemoryProtectionScope.SameLogon);

            Console.WriteLine($"Decrypted data: {UnicodeEncoding.ASCII.GetString(toEncrypt)}");

            ///////////////////////////////
            //
            // Data Encryption - ProtectedData
            //
            ///////////////////////////////

            // Create the original data to be encrypted
            toEncrypt = UnicodeEncoding.ASCII.GetBytes("This is some data of any length.");

            // Create a file.
            FileStream fStream = new FileStream("Data.dat", FileMode.OpenOrCreate);

            // Create some random entropy.
            byte[] entropy = CreateRandomEntropy();

            Console.WriteLine();
            Console.WriteLine($"Original data: {UnicodeEncoding.ASCII.GetString(toEncrypt)}");
            Console.WriteLine("Encrypting and writing to disk...");

            // Encrypt a copy of the data to the stream.
            int bytesWritten = EncryptDataToStream(toEncrypt, entropy, DataProtectionScope.CurrentUser, fStream);

            fStream.Close();

            Console.WriteLine("Reading data from disk and decrypting...");

            // Open the file.
            fStream = new FileStream("Data.dat", FileMode.Open);

            // Read from the stream and decrypt the data.
            byte[] decryptData = DecryptDataFromStream(entropy, DataProtectionScope.CurrentUser, fStream, bytesWritten);

            fStream.Close();

            Console.WriteLine($"Decrypted data: {UnicodeEncoding.ASCII.GetString(decryptData)}");
        }
        catch (Exception e)
        {
            Console.WriteLine($"ERROR: {e.Message}");
        }
    }

    public static void EncryptInMemoryData(byte[] Buffer, MemoryProtectionScope Scope )
    {
        if (Buffer == null)
            throw new ArgumentNullException(nameof(Buffer));
        if (Buffer.Length <= 0)
            throw new ArgumentException("The buffer length was 0.", nameof(Buffer));

        // Encrypt the data in memory. The result is stored in the same array as the original data.
        ProtectedMemory.Protect(Buffer, Scope);
    }

    public static void DecryptInMemoryData(byte[] Buffer, MemoryProtectionScope Scope)
    {
        if (Buffer == null)
            throw new ArgumentNullException(nameof(Buffer));
        if (Buffer.Length <= 0)
            throw new ArgumentException("The buffer length was 0.", nameof(Buffer));

        // Decrypt the data in memory. The result is stored in the same array as the original data.
        ProtectedMemory.Unprotect(Buffer, Scope);
    }

    public static byte[] CreateRandomEntropy()
    {
        // Create a byte array to hold the random value.
        byte[] entropy = new byte[16];

        // Create a new instance of the RNGCryptoServiceProvider.
        // Fill the array with a random value.
        new RNGCryptoServiceProvider().GetBytes(entropy);

        // Return the array.
        return entropy;
    }

    public static int EncryptDataToStream(byte[] Buffer, byte[] Entropy, DataProtectionScope Scope, Stream S)
    {
        if (Buffer == null)
            throw new ArgumentNullException(nameof(Buffer));
        if (Buffer.Length <= 0)
            throw new ArgumentException("The buffer length was 0.", nameof(Buffer));
        if (Entropy == null)
            throw new ArgumentNullException(nameof(Entropy));
        if (Entropy.Length <= 0)
            throw new ArgumentException("The entropy length was 0.", nameof(Entropy));
        if (S == null)
            throw new ArgumentNullException(nameof(S));

        int length = 0;

        // Encrypt the data and store the result in a new byte array. The original data remains unchanged.
        byte[] encryptedData = ProtectedData.Protect(Buffer, Entropy, Scope);

        // Write the encrypted data to a stream.
        if (S.CanWrite && encryptedData != null)
        {
            S.Write(encryptedData, 0, encryptedData.Length);

            length = encryptedData.Length;
        }

        // Return the length that was written to the stream.
        return length;
    }

    public static byte[] DecryptDataFromStream(byte[] Entropy, DataProtectionScope Scope, Stream S, int Length)
    {
        if (S == null)
            throw new ArgumentNullException(nameof(S));
        if (Length <= 0 )
            throw new ArgumentException("The given length was 0.", nameof(Length));
        if (Entropy == null)
            throw new ArgumentNullException(nameof(Entropy));
        if (Entropy.Length <= 0)
            throw new ArgumentException("The entropy length was 0.", nameof(Entropy));

        byte[] inBuffer = new byte[Length];
        byte[] outBuffer;

        // Read the encrypted data from a stream.
        if (S.CanRead)
        {
            S.Read(inBuffer, 0, Length);

            outBuffer = ProtectedData.Unprotect(inBuffer, Entropy, Scope);
        }
        else
        {
            throw new IOException("Could not read the stream.");
        }

        // Return the decrypted data
        return outBuffer;
    }
}
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography



Public Module MemoryProtectionSample

    Sub Main()
        Run()

    End Sub


    Sub Run()
        Try

            ''''''''''''''''''''''''''''''''''''
            '
            ' Memory Encryption - ProtectedMemory
            '
            ''''''''''''''''''''''''''''''''''''
            ' Create the original data to be encrypted (The data length should be a multiple of 16).
            Dim toEncrypt As Byte() = UnicodeEncoding.ASCII.GetBytes("ThisIsSomeData16")

            Console.WriteLine("Original data: " + UnicodeEncoding.ASCII.GetString(toEncrypt))
            Console.WriteLine("Encrypting...")

            ' Encrypt the data in memory.
            EncryptInMemoryData(toEncrypt, MemoryProtectionScope.SameLogon)

            Console.WriteLine("Encrypted data: " + UnicodeEncoding.ASCII.GetString(toEncrypt))
            Console.WriteLine("Decrypting...")

            ' Decrypt the data in memory.
            DecryptInMemoryData(toEncrypt, MemoryProtectionScope.SameLogon)

            Console.WriteLine("Decrypted data: " + UnicodeEncoding.ASCII.GetString(toEncrypt))


            ''''''''''''''''''''''''''''''''''''
            '
            ' Data Encryption - ProtectedData
            '
            ''''''''''''''''''''''''''''''''''''
            ' Create the original data to be encrypted
            toEncrypt = UnicodeEncoding.ASCII.GetBytes("This is some data of any length.")

            ' Create a file.
            Dim fStream As New FileStream("Data.dat", FileMode.OpenOrCreate)

            ' Create some random entropy.
            Dim entropy As Byte() = CreateRandomEntropy()

            Console.WriteLine()
            Console.WriteLine("Original data: " + UnicodeEncoding.ASCII.GetString(toEncrypt))
            Console.WriteLine("Encrypting and writing to disk...")

            ' Encrypt a copy of the data to the stream.
            Dim bytesWritten As Integer = EncryptDataToStream(toEncrypt, entropy, DataProtectionScope.CurrentUser, fStream)

            fStream.Close()

            Console.WriteLine("Reading data from disk and decrypting...")

            ' Open the file.
            fStream = New FileStream("Data.dat", FileMode.Open)

            ' Read from the stream and decrypt the data.
            Dim decryptData As Byte() = DecryptDataFromStream(entropy, DataProtectionScope.CurrentUser, fStream, bytesWritten)

            fStream.Close()

            Console.WriteLine("Decrypted data: " + UnicodeEncoding.ASCII.GetString(decryptData))


        Catch e As Exception
            Console.WriteLine("ERROR: " + e.Message)
        End Try

    End Sub



    Sub EncryptInMemoryData(ByVal Buffer() As Byte, ByVal Scope As MemoryProtectionScope)
        If Buffer Is Nothing Then
            Throw New ArgumentNullException("Buffer")
        End If
        If Buffer.Length <= 0 Then
            Throw New ArgumentException("Buffer")
        End If

        ' Encrypt the data in memory. The result is stored in the same array as the original data.
        ProtectedMemory.Protect(Buffer, Scope)

    End Sub


    Sub DecryptInMemoryData(ByVal Buffer() As Byte, ByVal Scope As MemoryProtectionScope)
        If Buffer Is Nothing Then
            Throw New ArgumentNullException("Buffer")
        End If
        If Buffer.Length <= 0 Then
            Throw New ArgumentException("Buffer")
        End If

        ' Decrypt the data in memory. The result is stored in the same array as the original data.
        ProtectedMemory.Unprotect(Buffer, Scope)

    End Sub


    Function CreateRandomEntropy() As Byte()
        ' Create a byte array to hold the random value.
        Dim entropy(15) As Byte

        ' Create a new instance of the RNGCryptoServiceProvider.
        ' Fill the array with a random value.
        Dim RNG As New RNGCryptoServiceProvider()

        RNG.GetBytes(entropy)

        ' Return the array.
        Return entropy

    End Function 'CreateRandomEntropy



    Function EncryptDataToStream(ByVal Buffer() As Byte, ByVal Entropy() As Byte, ByVal Scope As DataProtectionScope, ByVal S As Stream) As Integer
        If Buffer Is Nothing Then
            Throw New ArgumentNullException("Buffer")
        End If
        If Buffer.Length <= 0 Then
            Throw New ArgumentException("Buffer")
        End If
        If Entropy Is Nothing Then
            Throw New ArgumentNullException("Entropy")
        End If
        If Entropy.Length <= 0 Then
            Throw New ArgumentException("Entropy")
        End If
        If S Is Nothing Then
            Throw New ArgumentNullException("S")
        End If
        Dim length As Integer = 0

        ' Encrypt the data and store the result in a new byte array. The original data remains unchanged.
        Dim encryptedData As Byte() = ProtectedData.Protect(Buffer, Entropy, Scope)

        ' Write the encrypted data to a stream.
        If S.CanWrite AndAlso Not (encryptedData Is Nothing) Then
            S.Write(encryptedData, 0, encryptedData.Length)

            length = encryptedData.Length
        End If

        ' Return the length that was written to the stream. 
        Return length

    End Function 'EncryptDataToStream


    Function DecryptDataFromStream(ByVal Entropy() As Byte, ByVal Scope As DataProtectionScope, ByVal S As Stream, ByVal Length As Integer) As Byte()
        If S Is Nothing Then
            Throw New ArgumentNullException("S")
        End If
        If Length <= 0 Then
            Throw New ArgumentException("Length")
        End If
        If Entropy Is Nothing Then
            Throw New ArgumentNullException("Entropy")
        End If
        If Entropy.Length <= 0 Then
            Throw New ArgumentException("Entropy")
        End If


        Dim inBuffer(Length - 1) As Byte
        Dim outBuffer() As Byte

        ' Read the encrypted data from a stream.
        If S.CanRead Then
            S.Read(inBuffer, 0, Length)

            outBuffer = ProtectedData.Unprotect(inBuffer, Entropy, Scope)
        Else
            Throw New IOException("Could not read the stream.")
        End If

        ' Return the unencrypted data as byte array. 
        Return outBuffer

    End Function 'DecryptDataFromStream 
End Module 'MemoryProtectionSample

Kompilowanie kodu

W tym przykładzie kompiluje się i jest uruchamiany tylko wtedy, gdy jest przeznaczony program .NET Framework i działa w systemie Windows.

Zobacz też