RijndaelManaged.CreateDecryptor メソッド

  • リファレンス

定義

名前空間:
System.Security.Cryptography
アセンブリ:
System.Security.Cryptography.Algorithms.dll
アセンブリ:
System.Security.Cryptography.dll
アセンブリ:
netstandard.dll
アセンブリ:
mscorlib.dll

対称復号化オブジェクトを作成します。

オーバーロード

CreateDecryptor()

現在の Key プロパティおよび初期化ベクター (IV) を使用して、対称復号化オブジェクトを作成します。
CreateDecryptor(Byte[], Byte[])

指定した Rijndael および初期化ベクター (Key) を使用して、対称 IV 復号化オブジェクトを作成します。

CreateDecryptor()

ソース:
RijndaelManaged.cs
ソース:
RijndaelManaged.cs
ソース:
RijndaelManaged.cs

現在の Key プロパティおよび初期化ベクター (IV) を使用して、対称復号化オブジェクトを作成します。

public:
 override System::Security::Cryptography::ICryptoTransform ^ CreateDecryptor();
public override System.Security.Cryptography.ICryptoTransform CreateDecryptor ();
override this.CreateDecryptor : unit -> System.Security.Cryptography.ICryptoTransform
Public Overrides Function CreateDecryptor () As ICryptoTransform

戻り値

ICryptoTransform

対称復号化オブジェクト。

注釈

このメソッドは、同じシグネチャを持つ オーバーロードを CreateEncryptor 使用して作成された暗号化されたメッセージを復号化します。

適用対象

CreateDecryptor(Byte[], Byte[])

ソース:
RijndaelManaged.cs
ソース:
RijndaelManaged.cs
ソース:
RijndaelManaged.cs

指定した Rijndael および初期化ベクター (Key) を使用して、対称 IV 復号化オブジェクトを作成します。

public:
 override System::Security::Cryptography::ICryptoTransform ^ CreateDecryptor(cli::array <System::Byte> ^ rgbKey, cli::array <System::Byte> ^ rgbIV);
public override System.Security.Cryptography.ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[]? rgbIV);
public override System.Security.Cryptography.ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[] rgbIV);
override this.CreateDecryptor : byte[] * byte[] -> System.Security.Cryptography.ICryptoTransform
Public Overrides Function CreateDecryptor (rgbKey As Byte(), rgbIV As Byte()) As ICryptoTransform

パラメーター

rgbKey
Byte[]

対称アルゴリズムで使用する共有キー。 キー サイズは、128、192、または 256 ビットにする必要があります。

rgbIV
Byte[]

対称アルゴリズムで使用する IV。

戻り値

ICryptoTransform

対称 Rijndael 復号化オブジェクト。

例外

ArgumentNullException

rgbKey パラメーターが null です。

または

rgbIV パラメーターが null です。

CryptographicException

Mode プロパティの値が ECB、CBC、または CFB ではありません。

例

次のコード例では、 メソッドを使用 CreateDecryptor して、同じシグネチャ パラメーターでエンコードされたメッセージを復号化する方法を示します。

#using <System.dll>

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


class RijndaelMemoryExample
{
public:
    static array<Byte>^ encryptStringToBytes_AES(String^ plainText, array<Byte>^ Key, array<Byte>^ IV)
    {
        // Check arguments.
        if (!plainText || plainText->Length <= 0)
            throw gcnew ArgumentNullException("plainText");
        if (!Key || Key->Length <= 0)
            throw gcnew ArgumentNullException("Key");
        if (!IV  || IV->Length <= 0)
            throw gcnew ArgumentNullException("IV");

        // Declare the streams used
        // to encrypt to an in memory
        // array of bytes.
        MemoryStream^   msEncrypt;
        CryptoStream^   csEncrypt;
        StreamWriter^   swEncrypt;

        // Declare the RijndaelManaged object
        // used to encrypt the data.
        RijndaelManaged^ aesAlg;

        try
        {
            // Create a RijndaelManaged object
            // with the specified key and IV.
            aesAlg = gcnew RijndaelManaged();
            aesAlg->Padding = PaddingMode::PKCS7;
            aesAlg->Key = Key;
            aesAlg->IV = IV;

            // Create an encryptor to perform the stream transform.
            ICryptoTransform^ encryptor = aesAlg->CreateEncryptor(aesAlg->Key, aesAlg->IV);

            // Create the streams used for encryption.
            msEncrypt = gcnew MemoryStream();
            csEncrypt = gcnew CryptoStream(msEncrypt, encryptor, CryptoStreamMode::Write);
            swEncrypt = gcnew StreamWriter(csEncrypt);

            //Write all data to the stream.
            swEncrypt->Write(plainText);
            swEncrypt->Flush();
            csEncrypt->FlushFinalBlock();
            msEncrypt->Flush();
        }
        finally
        {
            // Clean things up.

            // Close the streams.
            if(swEncrypt)
                swEncrypt->Close();
            if (csEncrypt)
                csEncrypt->Close();


            // Clear the RijndaelManaged object.
            if (aesAlg)
                aesAlg->Clear();
        }

        // Return the encrypted bytes from the memory stream.
        return msEncrypt->ToArray();
    }

    static String^ decryptStringFromBytes_AES(array<Byte>^ cipherText, array<Byte>^ Key, array<Byte>^ IV)
    {
        // Check arguments.
        if (!cipherText || cipherText->Length <= 0)
            throw gcnew ArgumentNullException("cipherText");
        if (!Key || Key->Length <= 0)
            throw gcnew ArgumentNullException("Key");
        if (!IV || IV->Length <= 0)
            throw gcnew ArgumentNullException("IV");

        // TDeclare the streams used
        // to decrypt to an in memory
        // array of bytes.
        MemoryStream^ msDecrypt;
        CryptoStream^ csDecrypt;
        StreamReader^ srDecrypt;

        // Declare the RijndaelManaged object
        // used to decrypt the data.
        RijndaelManaged^ aesAlg;

        // Declare the string used to hold
        // the decrypted text.
        String^ plaintext;

        try
        {
            // Create a RijndaelManaged object
            // with the specified key and IV.
            aesAlg = gcnew RijndaelManaged();
            aesAlg->Padding = PaddingMode::PKCS7;
            aesAlg->Key = Key;
            aesAlg->IV = IV;

            // Create a decryptor to perform the stream transform.
            ICryptoTransform^ decryptor = aesAlg->CreateDecryptor(aesAlg->Key, aesAlg->IV);

            // Create the streams used for decryption.
            msDecrypt = gcnew MemoryStream(cipherText);
            csDecrypt = gcnew CryptoStream(msDecrypt, decryptor, CryptoStreamMode::Read);
            srDecrypt = gcnew StreamReader(csDecrypt);

            // Read the decrypted bytes from the decrypting stream
            // and place them in a string.
            plaintext = srDecrypt->ReadToEnd();
        }
        finally
        {
            // Clean things up.

            // Close the streams.
            if (srDecrypt)
                srDecrypt->Close();
            if (csDecrypt)
                csDecrypt->Close();
            if (msDecrypt)
                msDecrypt->Close();

            // Clear the RijndaelManaged object.
            if (aesAlg)
                aesAlg->Clear();
        }

        return plaintext;
    }
};

int main()
{
    try
    {
        String^ original = "Here is some data to encrypt!";

        // Create a new instance of the RijndaelManaged
        // class.  This generates a new key and initialization
        // vector (IV).
        RijndaelManaged^ myRijndael = gcnew RijndaelManaged();

        // Encrypt the string to an array of bytes.
        array<Byte>^ encrypted = RijndaelMemoryExample::encryptStringToBytes_AES(original, myRijndael->Key, myRijndael->IV);

        // Decrypt the bytes to a string.
        String^ roundtrip = RijndaelMemoryExample::decryptStringFromBytes_AES(encrypted, myRijndael->Key, myRijndael->IV);

        //Display the original data and the decrypted data.
        Console::WriteLine("Original:   {0}", original);
        Console::WriteLine("Round Trip: {0}", roundtrip);
    }
    catch (Exception^ e)
    {
        Console::WriteLine("Error: {0}", e->Message);
    }

    return 0;
}

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

namespace RijndaelManaged_Example
{
    class RijndaelExample
    {
        public static void Main()
        {
            try
            {

                string original = "Here is some data to encrypt!";

                // Create a new instance of the RijndaelManaged
                // class.  This generates a new key and initialization
                // vector (IV).
                using (RijndaelManaged myRijndael = new RijndaelManaged())
                {

                    myRijndael.GenerateKey();
                    myRijndael.GenerateIV();
                    // Encrypt the string to an array of bytes.
                    byte[] encrypted = EncryptStringToBytes(original, myRijndael.Key, myRijndael.IV);

                    // Decrypt the bytes to a string.
                    string roundtrip = DecryptStringFromBytes(encrypted, myRijndael.Key, myRijndael.IV);

                    //Display the original data and the decrypted data.
                    Console.WriteLine("Original:   {0}", original);
                    Console.WriteLine("Round Trip: {0}", roundtrip);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Error: {0}", e.Message);
            }
        }
        static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV)
        {
            // Check arguments.
            if (plainText == null || plainText.Length <= 0)
                throw new ArgumentNullException("plainText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("IV");
            byte[] encrypted;
            // Create an RijndaelManaged object
            // with the specified key and IV.
            using (RijndaelManaged rijAlg = new RijndaelManaged())
            {
                rijAlg.Key = Key;
                rijAlg.IV = IV;

                // Create an encryptor to perform the stream transform.
                ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for encryption.
                using (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                        {

                            //Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }
                    }

                    encrypted = msEncrypt.ToArray();
                }
            }

            // Return the encrypted bytes from the memory stream.
            return encrypted;
        }

        static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV)
        {
            // Check arguments.
            if (cipherText == null || cipherText.Length <= 0)
                throw new ArgumentNullException("cipherText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("IV");

            // Declare the string used to hold
            // the decrypted text.
            string plaintext = null;

            // Create an RijndaelManaged object
            // with the specified key and IV.
            using (RijndaelManaged rijAlg = new RijndaelManaged())
            {
                rijAlg.Key = Key;
                rijAlg.IV = IV;

                // Create a decryptor to perform the stream transform.
                ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for decryption.
                using (MemoryStream msDecrypt = new MemoryStream(cipherText))
                {
                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                        {
                            // Read the decrypted bytes from the decrypting stream
                            // and place them in a string.
                            plaintext = srDecrypt.ReadToEnd();
                        }
                    }
                }
            }

            return plaintext;
        }
    }
}

Imports System.IO
Imports System.Security.Cryptography



Class RijndaelExample

    Public Shared Sub Main()
        Try

            Dim original As String = "Here is some data to encrypt!"

            ' Create a new instance of the RijndaelManaged
            ' class.  This generates a new key and initialization 
            ' vector (IV).
            Using myRijndael As New RijndaelManaged()
            
                myRijndael.GenerateKey()
                myRijndael.GenerateIV()

                ' Encrypt the string to an array of bytes.
                Dim encrypted As Byte() = EncryptStringToBytes(original, myRijndael.Key, myRijndael.IV)

                ' Decrypt the bytes to a string.
                Dim roundtrip As String = DecryptStringFromBytes(encrypted, myRijndael.Key, myRijndael.IV)

                'Display the original data and the decrypted data.
                Console.WriteLine("Original:   {0}", original)
                Console.WriteLine("Round Trip: {0}", roundtrip)
            End Using
        Catch e As Exception
            Console.WriteLine("Error: {0}", e.Message)
        End Try

    End Sub

    Shared Function EncryptStringToBytes(ByVal plainText As String, ByVal Key() As Byte, ByVal IV() As Byte) As Byte()
        ' Check arguments.
        If plainText Is Nothing OrElse plainText.Length <= 0 Then
            Throw New ArgumentNullException("plainText")
        End If
        If Key Is Nothing OrElse Key.Length <= 0 Then
            Throw New ArgumentNullException("Key")
        End If
        If IV Is Nothing OrElse IV.Length <= 0 Then
            Throw New ArgumentNullException("IV")
        End If
        Dim encrypted() As Byte
        
        ' Create an RijndaelManaged object
        ' with the specified key and IV.
        Using rijAlg As New RijndaelManaged()

            rijAlg.Key = Key
            rijAlg.IV = IV

            ' Create an encryptor to perform the stream transform.
            Dim encryptor As ICryptoTransform = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV)
            ' Create the streams used for encryption.
            Using msEncrypt As New MemoryStream()
                Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)
                    Using swEncrypt As New StreamWriter(csEncrypt)
                        'Write all data to the stream.
                        swEncrypt.Write(plainText)
                    End Using
                    encrypted = msEncrypt.ToArray()
                End Using
            End Using
        End Using

        ' Return the encrypted bytes from the memory stream.
        Return encrypted

    End Function 'EncryptStringToBytes

    Shared Function DecryptStringFromBytes(ByVal cipherText() As Byte, ByVal Key() As Byte, ByVal IV() As Byte) As String
        ' Check arguments.
        If cipherText Is Nothing OrElse cipherText.Length <= 0 Then
            Throw New ArgumentNullException("cipherText")
        End If
        If Key Is Nothing OrElse Key.Length <= 0 Then
            Throw New ArgumentNullException("Key")
        End If
        If IV Is Nothing OrElse IV.Length <= 0 Then
            Throw New ArgumentNullException("IV")
        End If
        ' Declare the string used to hold
        ' the decrypted text.
        Dim plaintext As String = Nothing

        ' Create an RijndaelManaged object
        ' with the specified key and IV.
        Using rijAlg As New RijndaelManaged
            rijAlg.Key = Key
            rijAlg.IV = IV

            ' Create a decryptor to perform the stream transform.
            Dim decryptor As ICryptoTransform = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV)

            ' Create the streams used for decryption.
            Using msDecrypt As New MemoryStream(cipherText)

                Using csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)

                    Using srDecrypt As New StreamReader(csDecrypt)


                        ' Read the decrypted bytes from the decrypting stream
                        ' and place them in a string.
                        plaintext = srDecrypt.ReadToEnd()
                    End Using
                End Using
            End Using
        End Using

        Return plaintext

    End Function 'DecryptStringFromBytes 
End Class

注釈

このメソッドは、同じシグネチャを持つ オーバーロードを CreateEncryptor 使用して作成された暗号化されたメッセージを復号化します。

サイズは rgbkey 、128 ビット、192 ビット、または 256 ビットである必要があります。

こちらもご覧ください

適用対象