RSAOAEPKeyExchangeDeformatter.DecryptKeyExchange(Byte[]) Method
Definition
Important
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Extracts secret information from the encrypted key exchange data.
public:
override cli::array <System::Byte> ^ DecryptKeyExchange(cli::array <System::Byte> ^ rgbData);
public override byte[] DecryptKeyExchange (byte[] rgbData);
override this.DecryptKeyExchange : byte[] -> byte[]
Public Overrides Function DecryptKeyExchange (rgbData As Byte()) As Byte()
Parameters
- rgbData
- Byte[]
The key exchange data within which the secret information is hidden.
Returns
The secret information derived from the key exchange data.
Exceptions
The key exchange data verification has failed.
The key is missing.
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
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);
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)
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)
cs.Close()
Dim message As String = Encoding.UTF8.GetString(plaintext.ToArray())
Console.WriteLine(message)
End Using
End Using
End Using
End Sub
Remarks
You must specify a key before calling this method.