RSAOAEPKeyExchangeFormatter クラス


RSA を使用して、OAEP (最適非対称暗号化パディング) キー交換データを作成します。Creates Optimal Asymmetric Encryption Padding (OAEP) key exchange data using RSA.

public ref class RSAOAEPKeyExchangeFormatter : System::Security::Cryptography::AsymmetricKeyExchangeFormatter
public class RSAOAEPKeyExchangeFormatter : System.Security.Cryptography.AsymmetricKeyExchangeFormatter
type RSAOAEPKeyExchangeFormatter = class
    inherit AsymmetricKeyExchangeFormatter
Public Class RSAOAEPKeyExchangeFormatter
Inherits AsymmetricKeyExchangeFormatter

次の例では、RSAOAEPKeyExchangeFormatter クラスを使用して、メッセージ受信者の交換キーを作成する方法を示します。The following example shows how to use the RSAOAEPKeyExchangeFormatter class to create an exchange key for a message recipient.

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

class Alice
    public static void Main(string[] args)
        using (Bob bob = new Bob())
            using (RSACryptoServiceProvider rsaKey = new RSACryptoServiceProvider())
                // Get Bob's public key
                byte[] encryptedSessionKey = null;
                byte[] encryptedMessage = null;
                byte[] iv = null;
                Send(rsaKey, "Secret message", out iv, out encryptedSessionKey, out encryptedMessage);
                bob.Receive(iv, encryptedSessionKey, encryptedMessage);

    private static void Send(RSA key, string secretMessage, out byte[] iv, out byte[] encryptedSessionKey, out byte[] encryptedMessage)
        using (Aes aes = new AesCryptoServiceProvider())
            iv = aes.IV;

            // Encrypt the session key
            RSAOAEPKeyExchangeFormatter keyFormatter = new RSAOAEPKeyExchangeFormatter(key);
            encryptedSessionKey = keyFormatter.CreateKeyExchange(aes.Key, typeof(Aes));

            // Encrypt the message
            using (MemoryStream ciphertext = new MemoryStream())
            using (CryptoStream cs = new CryptoStream(ciphertext, aes.CreateEncryptor(), CryptoStreamMode.Write))
                byte[] plaintextMessage = Encoding.UTF8.GetBytes(secretMessage);
                cs.Write(plaintextMessage, 0, plaintextMessage.Length);

                encryptedMessage = ciphertext.ToArray();
public class Bob : IDisposable
    public byte[] key;
    private RSACryptoServiceProvider rsaKey = new RSACryptoServiceProvider();
    public Bob()
        key = rsaKey.ExportCspBlob(false);
    public void Receive(byte[] iv, byte[] encryptedSessionKey, byte[] encryptedMessage)

        using (Aes aes = new AesCryptoServiceProvider())
            aes.IV = iv;

            // Decrypt the session key
            RSAOAEPKeyExchangeDeformatter keyDeformatter = new RSAOAEPKeyExchangeDeformatter(rsaKey);
            aes.Key = keyDeformatter.DecryptKeyExchange(encryptedSessionKey);

            // Decrypt the message
            using (MemoryStream plaintext = new MemoryStream())
            using (CryptoStream cs = new CryptoStream(plaintext, aes.CreateDecryptor(), CryptoStreamMode.Write))
                cs.Write(encryptedMessage, 0, encryptedMessage.Length);

                string message = Encoding.UTF8.GetString(plaintext.ToArray());
    public void Dispose()
Imports System.IO
Imports System.Security.Cryptography
Imports System.Text

Class Alice

    Public Shared Sub Main(ByVal args() As String)
        Using bob As New Bob()
            Using rsaKey As New RSACryptoServiceProvider()
                    ' Get Bob's public key
                    Dim encryptedSessionKey As Byte() = Nothing
                    Dim encryptedMessage As Byte() = Nothing
                    Dim iv As Byte() = Nothing
                    Send(rsaKey, "Secret message", iv, encryptedSessionKey, encryptedMessage)
                    bob.Receive(iv, encryptedSessionKey, encryptedMessage)
            End Using
        End Using

    End Sub

    Private Shared Sub Send(ByVal key As RSA, ByVal secretMessage As String, ByRef iv() As Byte, ByRef encryptedSessionKey() As Byte, ByRef encryptedMessage() As Byte)
        Using aes = New AesCryptoServiceProvider()

            iv = aes.IV

            ' Encrypt the session key
            Dim keyFormatter As New RSAOAEPKeyExchangeFormatter(key)
            encryptedSessionKey = keyFormatter.CreateKeyExchange(aes.Key, GetType(Aes))

            ' Encrypt the message
            Using ciphertext As New MemoryStream()
                Using cs As New CryptoStream(ciphertext, aes.CreateEncryptor(), CryptoStreamMode.Write)
                    Dim plaintextMessage As Byte() = Encoding.UTF8.GetBytes(secretMessage)
                    cs.Write(plaintextMessage, 0, plaintextMessage.Length)

                    encryptedMessage = ciphertext.ToArray()
                End Using
            End Using
        End Using

    End Sub
End Class

Public Class Bob
    Implements IDisposable
    Public key() As Byte
    Private rsaKey As New RSACryptoServiceProvider()

    Public Sub New()
        key = rsaKey.ExportCspBlob(False)

    End Sub

    Public Sub Receive(ByVal iv() As Byte, ByVal encryptedSessionKey() As Byte, ByVal encryptedMessage() As Byte)

        Using aes = New AesCryptoServiceProvider()

            aes.IV = iv

            ' Decrypt the session key
            Dim keyDeformatter As New RSAOAEPKeyExchangeDeformatter(rsaKey)
            aes.Key = keyDeformatter.DecryptKeyExchange(encryptedSessionKey)

            ' Decrypt the message
            Using plaintext As New MemoryStream()
                Using cs As New CryptoStream(plaintext, aes.CreateDecryptor(), CryptoStreamMode.Write)
                        cs.Write(encryptedMessage, 0, encryptedMessage.Length)

                        Dim message As String = Encoding.UTF8.GetString(plaintext.ToArray())
                End Using
            End Using
        End Using

    End Sub
    Public Overloads Sub Dispose() Implements IDisposable.Dispose
    End Sub
End Class


キー交換を使用すると、送信者は、対称暗号化アルゴリズムでキーとして使用できるランダムなデータなどのシークレット情報を作成し、暗号化を使用して目的の受信者に送信することができます。Key exchange allows a sender to create secret information, for example, random data that can be used as a key in a symmetric encryption algorithm, and use encryption to send it to the intended recipient.

キー交換を受信して秘密情報を抽出するには、RSAOAEPKeyExchangeDeformatter を使用します。Use RSAOAEPKeyExchangeDeformatter to receive the key exchange and extract the secret information from it.


キー交換を成功させるには、操作の詳細情報を慎重に実行する必要があるため、提供されている基本的な機能から独自のキー交換メソッドを作成しないことを強くお勧めします。It is highly recommended that you not attempt to create your own key exchange method from the basic functionality provided, because many details of the operation must be performed carefully in order for the key exchange to be successful.



RSAOAEPKeyExchangeFormatter クラスの新しいインスタンスを初期化します。Initializes a new instance of the RSAOAEPKeyExchangeFormatter class.


指定したキーで、RSAOAEPKeyExchangeFormatter クラスの新しいインスタンスを初期化します。Initializes a new instance of the RSAOAEPKeyExchangeFormatter class with the specified key.



キー交換の作成プロセスでパディングの作成に使用するパラメーターを取得または設定します。Gets or sets the parameter used to create padding in the key exchange creation process.


OAEP (最適非対称暗号化パディング) キー交換のパラメーターを取得します。Gets the parameters for the Optimal Asymmetric Encryption Padding (OAEP) key exchange.


キー交換の作成に使用する乱数ジェネレーター アルゴリズムを取得または設定します。Gets or sets the random number generator algorithm to use in the creation of the key exchange.



指定された入力データから暗号化したキー交換データを作成します。Creates the encrypted key exchange data from the specified input data.

CreateKeyExchange(Byte[], Type)

指定された入力データから暗号化したキー交換データを作成します。Creates the encrypted key exchange data from the specified input data.


指定されたオブジェクトが現在のオブジェクトと等しいかどうかを判定します。Determines whether the specified object is equal to the current object.

(継承元 Object)

既定のハッシュ関数として機能します。Serves as the default hash function.

(継承元 Object)

現在のインスタンスの Type を取得します。Gets the Type of the current instance.

(継承元 Object)

現在の Object の簡易コピーを作成します。Creates a shallow copy of the current Object.

(継承元 Object)

キー交換データの暗号化に使用する公開キーを設定します。Sets the public key to use for encrypting the key exchange data.


現在のオブジェクトを表す string を返します。Returns a string that represents the current object.

(継承元 Object)