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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;

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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