Rijndael コンストラクタ

.NET Framework クラス ライブラリ リファレンス

Rijndael コンストラクタ

Rijndael の新しいインスタンスを初期化します。

名前空間: System.Security.Cryptography
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Protected Sub New

Visual Basic (使用法)

Dim instance As New Rijndael

C#

protected Rijndael ()

C++

protected:
Rijndael ()

J#

protected Rijndael ()

JScript

protected function Rijndael ()

解説

抽象クラスのインスタンスは作成できません。アプリケーション コードは、派生クラスの新しいインスタンスを作成します。

このメソッドは、SymmetricAlgorithm のプロテクト フィールドを次の表に示す既定値で初期化します。

フィールド	既定値
KeySizeValue	256
BlockSizeValue	128
FeedbackSizeValue	128

使用例

Rijndael クラスを使用してデータを暗号化し、復号化する方法を次のコード例に示します。

Visual Basic

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

Module RijndaelSample

    Sub Main()
        Try
            ' Create a new Rijndael object to generate a key
            ' and initialization vector (IV).
            Dim RijndaelAlg As Rijndael = Rijndael.Create

            ' Create a string to encrypt.
            Dim sData As String
 = "Here is some data to encrypt."
            Dim FileName As String
 = "CText.txt"

            ' Encrypt text to a file using the file name, key, and IV.
            EncryptTextToFile(sData, FileName, RijndaelAlg.Key, RijndaelAlg.IV)

            ' Decrypt the text from a file using the file name, key,
 and IV.
            Dim Final As String
 = DecryptTextFromFile(FileName, RijndaelAlg.Key, RijndaelAlg.IV)

            ' Display the decrypted string to the console.
            Console.WriteLine(Final)
        Catch e As Exception
            Console.WriteLine(e.Message)
        End Try

        Console.ReadLine()

    End Sub


    Sub EncryptTextToFile(ByVal Data As
 String, ByVal FileName As
 String, ByVal Key() As Byte, ByVal IV() As Byte)
        Try
            ' Create or open the specified file.
            Dim fStream As FileStream = File.Open(FileName,
 FileMode.OpenOrCreate)

            ' Create a new Rijndael object.
            Dim RijndaelAlg As Rijndael = Rijndael.Create

            ' Create a CryptoStream using the FileStream 
            ' and the passed key and initialization vector (IV).
            Dim cStream As New
 CryptoStream(fStream, _
                                           RijndaelAlg.CreateEncryptor(Key, IV),
 _
                                           CryptoStreamMode.Write)

            ' Create a StreamWriter using the CryptoStream.
            Dim sWriter As New
 StreamWriter(cStream)

            Try

                ' Write the data to the stream 
                ' to encrypt it.
                sWriter.WriteLine(Data)
            Catch e As Exception

                Console.WriteLine("An error occurred: {0}",
 e.Message)

            Finally

                ' Close the streams and
                ' close the file.
                sWriter.Close()
                cStream.Close()
                fStream.Close()

            End Try
        Catch e As CryptographicException
            Console.WriteLine("A Cryptographic error occurred:
 {0}", e.Message)
        Catch e As UnauthorizedAccessException
            Console.WriteLine("A file error occurred: {0}",
 e.Message)
        End Try
    End Sub


    Function DecryptTextFromFile(ByVal FileName
 As String, ByVal Key()
 As Byte, ByVal IV() As Byte) As String
        Try
            ' Create or open the specified file. 
            Dim fStream As FileStream = File.Open(FileName,
 FileMode.OpenOrCreate)

            ' Create a new Rijndael object.
            Dim RijndaelAlg As Rijndael = Rijndael.Create

            ' Create a CryptoStream using the FileStream 
            ' and the passed key and initialization vector (IV).
            Dim cStream As New
 CryptoStream(fStream, _
                                            RijndaelAlg.CreateDecryptor(Key, IV),
 _
                                            CryptoStreamMode.Read)

            ' Create a StreamReader using the CryptoStream.
            Dim sReader As New
 StreamReader(cStream)

            ' Read the data from the stream 
            ' to decrypt it.
            Dim val As String
 = Nothing

            Try

                val = sReader.ReadLine()

            Catch e As Exception
                Console.WriteLine("An Cerror occurred: {0}",
 e.Message)
            Finally
                ' Close the streams and
                ' close the file.
                sReader.Close()
                cStream.Close()
                fStream.Close()


            End Try

            ' Return the string. 
            Return val

        Catch e As CryptographicException
            Console.WriteLine("A Cryptographic error occurred:
 {0}", e.Message)
            Return Nothing
        Catch e As UnauthorizedAccessException
            Console.WriteLine("A file error occurred: {0}",
 e.Message)
            Return Nothing
        End Try
    End Function
End Module

C#

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

class RijndaelSample
{

    static void Main()
    {
        try
        {
            // Create a new Rijndael object to generate a key
            // and initialization vector (IV).
            Rijndael RijndaelAlg = Rijndael.Create();

            // Create a string to encrypt.
            string sData = "Here is some data to encrypt.";
            string FileName = "CText.txt";

            // Encrypt text to a file using the file name, key, and
 IV.
            EncryptTextToFile(sData, FileName, RijndaelAlg.Key, RijndaelAlg.IV);

            // Decrypt the text from a file using the file name, key,
 and IV.
            string Final = DecryptTextFromFile(FileName, RijndaelAlg.Key,
 RijndaelAlg.IV);

            // Display the decrypted string to the console.
            Console.WriteLine(Final);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

        Console.ReadLine();
    }

    public static void EncryptTextToFile(String
 Data, String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file.
            FileStream fStream = File.Open(FileName, FileMode.OpenOrCreate);

            // Create a new Rijndael object.
            Rijndael RijndaelAlg = Rijndael.Create();

            // Create a CryptoStream using the FileStream 
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream,
                RijndaelAlg.CreateEncryptor(Key, IV),
                CryptoStreamMode.Write);

            // Create a StreamWriter using the CryptoStream.
            StreamWriter sWriter = new StreamWriter(cStream);

            try
            {
                // Write the data to the stream 
                // to encrypt it.
                sWriter.WriteLine(Data);
            }
            catch (Exception e)
            {
                Console.WriteLine("An error occurred: {0}", e.Message);
            }
            finally
            {
                // Close the streams and
                // close the file.
                sWriter.Close();
                cStream.Close();
                fStream.Close();
            }
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
        }
        catch (UnauthorizedAccessException e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
        }

    }

    public static string
 DecryptTextFromFile(String FileName, byte[] Key, byte[] IV)
    {
        try
        {
            // Create or open the specified file. 
            FileStream fStream = File.Open(FileName, FileMode.OpenOrCreate);

            // Create a new Rijndael object.
            Rijndael RijndaelAlg = Rijndael.Create();

            // Create a CryptoStream using the FileStream 
            // and the passed key and initialization vector (IV).
            CryptoStream cStream = new CryptoStream(fStream,
                RijndaelAlg.CreateDecryptor(Key, IV),
                CryptoStreamMode.Read);

            // Create a StreamReader using the CryptoStream.
            StreamReader sReader = new StreamReader(cStream);

            string val = null;

            try
            {
                // Read the data from the stream 
                // to decrypt it.
                val = sReader.ReadLine();


            }
            catch (Exception e)
            {
                Console.WriteLine("An error occurred: {0}", e.Message);
            }
            finally
            {

                // Close the streams and
                // close the file.
                sReader.Close();
                cStream.Close();
                fStream.Close();
            }

            // Return the string. 
            return val;
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
        catch (UnauthorizedAccessException e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
            return null;
        }
    }
}

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0

参照

関連項目
Rijndael クラス
Rijndael メンバ
System.Security.Cryptography 名前空間
その他の技術情報
暗号サービス