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RSAOAEPKeyExchangeDeformatter.DecryptKeyExchange Method

Updated: March 2011

Extracts secret information from the encrypted key exchange data.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

public override byte[] DecryptKeyExchange(
	byte[] rgbData
)

Parameters

rgbData
Type: System.Byte[]

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

Return Value

Type: System.Byte[]
The secret information derived from the key exchange data.

ExceptionCondition
CryptographicException

The key exchange data verification has failed.

CryptographicUnexpectedOperationException

The key is missing.

You must specify a key before calling this method.

The following example shows how to use the DecryptKeyExchange(Byte[]) 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);
        }
    }
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

Date

History

Reason

March 2011

Replaced the example.

Customer feedback.

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