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RSAPKCS1KeyExchangeDeformatter.DecryptKeyExchange(Byte[]) Method

Definition

Extracts secret information from the encrypted key exchange data.

public:
 override cli::array <System::Byte> ^ DecryptKeyExchange(cli::array <System::Byte> ^ rgbIn);
public override byte[] DecryptKeyExchange (byte[] rgbIn);
override this.DecryptKeyExchange : byte[] -> byte[]
Public Overrides Function DecryptKeyExchange (rgbIn As Byte()) As Byte()

Parameters

rgbIn
Byte[]

The key exchange data within which the secret information is hidden.

Returns

Byte[]

The secret information derived from the key exchange data.

Exceptions

Examples

The following example shows how to use the DecryptKeyExchange method to recreate an exchange key from a message sender. This code example is part of a larger example provided for the RSAPKCS1KeyExchangeDeformatter class.

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 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

Remarks

You must specify a key before calling this method.

Applies to

See also