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RSAOAEPKeyExchangeDeformatter.DecryptKeyExchange Method

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 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);
        }
    }
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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