Rfc2898DeriveBytes クラス

定義

public ref class Rfc2898DeriveBytes : System::Security::Cryptography::DeriveBytes

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public class Rfc2898DeriveBytes : System.Security.Cryptography.DeriveBytes

public class Rfc2898DeriveBytes : System.Security.Cryptography.DeriveBytes

[System.Runtime.InteropServices.ComVisible(true)]
public class Rfc2898DeriveBytes : System.Security.Cryptography.DeriveBytes

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
type Rfc2898DeriveBytes = class
    inherit DeriveBytes

type Rfc2898DeriveBytes = class
    inherit DeriveBytes

[<System.Runtime.InteropServices.ComVisible(true)>]
type Rfc2898DeriveBytes = class
    inherit DeriveBytes

Public Class Rfc2898DeriveBytes
Inherits DeriveBytes

継承

Object

DeriveBytes

Rfc2898DeriveBytes

属性

UnsupportedOSPlatformAttribute ComVisibleAttribute

例

次のコード例では、 クラスを Rfc2898DeriveBytes 使用して、 クラスの 2 つの同じキーを Aes 作成します。 その後、キーを使用して一部のデータを暗号化および暗号化解除します。

using namespace System;
using namespace System::IO;
using namespace System::Text;
using namespace System::Security::Cryptography;

// Generate a key k1 with password pwd1 and salt salt1.
// Generate a key k2 with password pwd1 and salt salt1.
// Encrypt data1 with key k1 using symmetric encryption, creating edata1.
// Decrypt edata1 with key k2 using symmetric decryption, creating data2.
// data2 should equal data1.

int main()
{
   array<String^>^passwordargs = Environment::GetCommandLineArgs();
   String^ usageText = "Usage: RFC2898 <password>\nYou must specify the password for encryption.\n";

   //If no file name is specified, write usage text.
   if ( passwordargs->Length == 1 )
   {
      Console::WriteLine( usageText );
   }
   else
   {
      String^ pwd1 = passwordargs[ 1 ];
      
      array<Byte>^salt1 = gcnew array<Byte>(8);
      RNGCryptoServiceProvider ^ rngCsp = gcnew RNGCryptoServiceProvider();
         rngCsp->GetBytes(salt1);
      //data1 can be a string or contents of a file.
      String^ data1 = "Some test data";

      //The default iteration count is 1000 so the two methods use the same iteration count.
      int myIterations = 1000;

      try
      {
         Rfc2898DeriveBytes ^ k1 = gcnew Rfc2898DeriveBytes( pwd1,salt1,myIterations );
         Rfc2898DeriveBytes ^ k2 = gcnew Rfc2898DeriveBytes( pwd1,salt1 );

         // Encrypt the data.
         Aes^ encAlg = Aes::Create();
         encAlg->Key = k1->GetBytes( 16 );
         MemoryStream^ encryptionStream = gcnew MemoryStream;
         CryptoStream^ encrypt = gcnew CryptoStream( encryptionStream,encAlg->CreateEncryptor(),CryptoStreamMode::Write );
         array<Byte>^utfD1 = (gcnew System::Text::UTF8Encoding( false ))->GetBytes( data1 );

         encrypt->Write( utfD1, 0, utfD1->Length );
         encrypt->FlushFinalBlock();
         encrypt->Close();
         array<Byte>^edata1 = encryptionStream->ToArray();
         k1->Reset();

         // Try to decrypt, thus showing it can be round-tripped.
         Aes^ decAlg = Aes::Create();
         decAlg->Key = k2->GetBytes( 16 );
         decAlg->IV = encAlg->IV;
         MemoryStream^ decryptionStreamBacking = gcnew MemoryStream;
         CryptoStream^ decrypt = gcnew CryptoStream( decryptionStreamBacking,decAlg->CreateDecryptor(),CryptoStreamMode::Write );

         decrypt->Write( edata1, 0, edata1->Length );
         decrypt->Flush();
         decrypt->Close();
         k2->Reset();

         String^ data2 = (gcnew UTF8Encoding( false ))->GetString( decryptionStreamBacking->ToArray() );
         if (  !data1->Equals( data2 ) )
         {
            Console::WriteLine( "Error: The two values are not equal." );
         }
         else
         {
            Console::WriteLine( "The two values are equal." );
            Console::WriteLine( "k1 iterations: {0}", k1->IterationCount );
            Console::WriteLine( "k2 iterations: {0}", k2->IterationCount );
         }
      }

      catch ( Exception^ e ) 
      {
         Console::WriteLine( "Error: ", e );
      }
   }
}

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

public class rfc2898test
{
    // Generate a key k1 with password pwd1 and salt salt1.
    // Generate a key k2 with password pwd1 and salt salt1.
    // Encrypt data1 with key k1 using symmetric encryption, creating edata1.
    // Decrypt edata1 with key k2 using symmetric decryption, creating data2.
    // data2 should equal data1.

    private const string usageText = "Usage: RFC2898 <password>\nYou must specify the password for encryption.\n";
    public static void Main(string[] passwordargs)
    {
        //If no file name is specified, write usage text.
        if (passwordargs.Length == 0)
        {
            Console.WriteLine(usageText);
        }
        else
        {
            string pwd1 = passwordargs[0];
            // Create a byte array to hold the random value.
            byte[] salt1 = new byte[8];
            using (RNGCryptoServiceProvider rngCsp = new
RNGCryptoServiceProvider())
            {
                // Fill the array with a random value.
                rngCsp.GetBytes(salt1);
            }

            //data1 can be a string or contents of a file.
            string data1 = "Some test data";
            //The default iteration count is 1000 so the two methods use the same iteration count.
            int myIterations = 1000;
            try
            {
                Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1,
myIterations);
                Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);
                // Encrypt the data.
                Aes encAlg = Aes.Create();
                encAlg.Key = k1.GetBytes(16);
                MemoryStream encryptionStream = new MemoryStream();
                CryptoStream encrypt = new CryptoStream(encryptionStream,
encAlg.CreateEncryptor(), CryptoStreamMode.Write);
                byte[] utfD1 = new System.Text.UTF8Encoding(false).GetBytes(
data1);

                encrypt.Write(utfD1, 0, utfD1.Length);
                encrypt.FlushFinalBlock();
                encrypt.Close();
                byte[] edata1 = encryptionStream.ToArray();
                k1.Reset();

                // Try to decrypt, thus showing it can be round-tripped.
                Aes decAlg = Aes.Create();
                decAlg.Key = k2.GetBytes(16);
                decAlg.IV = encAlg.IV;
                MemoryStream decryptionStreamBacking = new MemoryStream();
                CryptoStream decrypt = new CryptoStream(
decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write);
                decrypt.Write(edata1, 0, edata1.Length);
                decrypt.Flush();
                decrypt.Close();
                k2.Reset();
                string data2 = new UTF8Encoding(false).GetString(
decryptionStreamBacking.ToArray());

                if (!data1.Equals(data2))
                {
                    Console.WriteLine("Error: The two values are not equal.");
                }
                else
                {
                    Console.WriteLine("The two values are equal.");
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount);
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Error: {0}", e);
            }
        }
    }
}

Imports System.IO
Imports System.Text
Imports System.Security.Cryptography



Public Class rfc2898test
    ' Generate a key k1 with password pwd1 and salt salt1.
    ' Generate a key k2 with password pwd1 and salt salt1.
    ' Encrypt data1 with key k1 using symmetric encryption, creating edata1.
    ' Decrypt edata1 with key k2 using symmetric decryption, creating data2.
    ' data2 should equal data1.
    Private Const usageText As String = "Usage: RFC2898 <password>" + vbLf + "You must specify the password for encryption." + vbLf

    Public Shared Sub Main(ByVal passwordargs() As String)
        'If no file name is specified, write usage text.
        If passwordargs.Length = 0 Then
            Console.WriteLine(usageText)
        Else
            Dim pwd1 As String = passwordargs(0)

            Dim salt1(8) As Byte
            Using rngCsp As New RNGCryptoServiceProvider()
                rngCsp.GetBytes(salt1)
            End Using
            'data1 can be a string or contents of a file.
            Dim data1 As String = "Some test data"
            'The default iteration count is 1000 so the two methods use the same iteration count.
            Dim myIterations As Integer = 1000
            Try
                Dim k1 As New Rfc2898DeriveBytes(pwd1, salt1, myIterations)
                Dim k2 As New Rfc2898DeriveBytes(pwd1, salt1)
                ' Encrypt the data.
                Dim encAlg As Aes = Aes.Create()
                encAlg.Key = k1.GetBytes(16)
                Dim encryptionStream As New MemoryStream()
                Dim encrypt As New CryptoStream(encryptionStream, encAlg.CreateEncryptor(), CryptoStreamMode.Write)
                Dim utfD1 As Byte() = New System.Text.UTF8Encoding(False).GetBytes(data1)
                encrypt.Write(utfD1, 0, utfD1.Length)
                encrypt.FlushFinalBlock()
                encrypt.Close()
                Dim edata1 As Byte() = encryptionStream.ToArray()
                k1.Reset()

                ' Try to decrypt, thus showing it can be round-tripped.
                Dim decAlg As Aes = Aes.Create()
                decAlg.Key = k2.GetBytes(16)
                decAlg.IV = encAlg.IV
                Dim decryptionStreamBacking As New MemoryStream()
                Dim decrypt As New CryptoStream(decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write)
                decrypt.Write(edata1, 0, edata1.Length)
                decrypt.Flush()
                decrypt.Close()
                k2.Reset()
                Dim data2 As String = New UTF8Encoding(False).GetString(decryptionStreamBacking.ToArray())

                If Not data1.Equals(data2) Then
                    Console.WriteLine("Error: The two values are not equal.")
                Else
                    Console.WriteLine("The two values are equal.")
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount)
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount)
                End If
            Catch e As Exception
                Console.WriteLine("Error: ", e)
            End Try
        End If

    End Sub
End Class

注釈

Rfc2898DeriveBytes はパスワード、salt、反復回数を受け取り、 メソッドの呼び出しを通じてキーを GetBytes 生成します。

RFC 2898 には、パスワードとソルトからキーと初期化ベクトル (IV) を作成するためのメソッドが含まれています。 パスワードベースのキー派生関数である PBKDF2 を使用して、事実上無制限の長さのキーを生成できる擬似ランダム関数を使用してキーを派生させることができます。 クラスを Rfc2898DeriveBytes 使用して、基本キーとその他のパラメーターから派生キーを生成できます。 パスワードベースのキー派生関数では、基本キーはパスワードであり、他のパラメーターは salt 値と反復カウントです。

PBKDF2 の詳細については、「PKCS #5: Password-Based Cryptography Specification Version 2.0」というタイトルの RFC 2898 を参照してください。 詳細については、セクション 5.2「PBKDF2」を参照してください。

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