RSAPKCS1KeyExchangeDeformatter Classe

Definizione

public ref class RSAPKCS1KeyExchangeDeformatter : System::Security::Cryptography::AsymmetricKeyExchangeDeformatter

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public class RSAPKCS1KeyExchangeDeformatter : System.Security.Cryptography.AsymmetricKeyExchangeDeformatter

public class RSAPKCS1KeyExchangeDeformatter : System.Security.Cryptography.AsymmetricKeyExchangeDeformatter

[System.Runtime.InteropServices.ComVisible(true)]
public class RSAPKCS1KeyExchangeDeformatter : System.Security.Cryptography.AsymmetricKeyExchangeDeformatter

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
type RSAPKCS1KeyExchangeDeformatter = class
    inherit AsymmetricKeyExchangeDeformatter

type RSAPKCS1KeyExchangeDeformatter = class
    inherit AsymmetricKeyExchangeDeformatter

[<System.Runtime.InteropServices.ComVisible(true)>]
type RSAPKCS1KeyExchangeDeformatter = class
    inherit AsymmetricKeyExchangeDeformatter

Public Class RSAPKCS1KeyExchangeDeformatter
Inherits AsymmetricKeyExchangeDeformatter

Ereditarietà

Object

AsymmetricKeyExchangeDeformatter

RSAPKCS1KeyExchangeDeformatter

Attributi

UnsupportedOSPlatformAttribute ComVisibleAttribute

Esempio

Nell'esempio seguente viene illustrato come usare la RSAPKCS1KeyExchangeDeformatter classe per ricreare una chiave di scambio da usare per decrittografare un messaggio.

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
                rsaKey.ImportCspBlob(bob.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
            RSAPKCS1KeyExchangeFormatter keyFormatter = new RSAPKCS1KeyExchangeFormatter(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);
                cs.Close();

                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
            RSAPKCS1KeyExchangeDeformatter keyDeformatter = new RSAPKCS1KeyExchangeDeformatter(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);
                cs.Close();

                string message = Encoding.UTF8.GetString(plaintext.ToArray());
                Console.WriteLine(message);
            }
        }
    }
    public void Dispose()
    {
        rsaKey.Dispose();
    }
}

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




Class Alice

    Public Shared Sub Main(ByVal args() As String)
        Dim bob As New Bob()
        Try
            Dim rsaKey As New RSACryptoServiceProvider()
            Try
                ' Get Bob's public key
                rsaKey.ImportCspBlob(bob.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)
            Finally
                rsaKey.Dispose()
            End Try
        Finally
            bob.Dispose()
        End Try

    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)
        Dim aes = New AesCryptoServiceProvider()
        Try
            iv = aes.IV

            ' Encrypt the session key
            Dim keyFormatter As New RSAPKCS1KeyExchangeFormatter(key)
            encryptedSessionKey = keyFormatter.CreateKeyExchange(aes.Key, GetType(Aes))

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

                    encryptedMessage = ciphertext.ToArray()
                Finally
                    cs.Dispose()
                End Try
            Finally
                ciphertext.Dispose()
            End Try
        Finally
            aes.Dispose()
        End Try

    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)

        Dim aes = New AesCryptoServiceProvider()
        Try
            aes.IV = iv

            ' Decrypt the session key
            Dim keyDeformatter As New RSAPKCS1KeyExchangeDeformatter(rsaKey)
            aes.Key = keyDeformatter.DecryptKeyExchange(encryptedSessionKey)

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

                    Dim message As String = Encoding.UTF8.GetString(plaintext.ToArray())
                    Console.WriteLine(message)
                Finally
                    cs.Dispose()
                End Try
            Finally
                plaintext.Dispose()
            End Try
        Finally
            aes.Dispose()
        End Try

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

Commenti

Lo scambio delle chiavi consente a un mittente di creare informazioni segrete ,ad esempio dati casuali che possono essere usati come chiave in un algoritmo di crittografia simmetrica) e usare la crittografia per inviarle al destinatario previsto.

Usare RSAPKCS1KeyExchangeFormatter per creare il messaggio di scambio delle chiavi usando l'algoritmo RSA .

Costruttori

Proprietà

Metodi

Si applica a

Vedi anche

• servizi crittografici