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AsymmetricKeyExchangeDeformatter.DecryptKeyExchange Method

When overridden in a derived class, extracts secret information from the encrypted key exchange data.

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

public abstract byte[] DecryptKeyExchange(
	byte[] rgb


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.

You must specify a key before calling an implementation of this method.

The following code example demonstrates how to override the DecryptKeyExchange method to create an encrypted key exchange for the specified input data. This code example is part of a larger example provided for the AsymmetricKeyExchangeDeformatter class.

// Create the encrypted key exchange data from the specified input 
// data. This method uses the RSACryptoServiceProvider only. To 
// support additional providers or provide custom decryption logic, 
// add logic to this member. 
public override byte[] DecryptKeyExchange(byte[] rgbData) 
    byte[] decryptedBytes = null;

    if (rsaKey != null)
        if (rsaKey is RSACryptoServiceProvider) 
            RSACryptoServiceProvider serviceProvder = 
                (RSACryptoServiceProvider) rsaKey;

            decryptedBytes = serviceProvder.Decrypt(rgbData, true);
        // Add custom decryption logic here.
        throw new CryptographicUnexpectedOperationException(

    return decryptedBytes;

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, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

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

.NET Compact Framework

Supported in: 3.5