RSAPKCS1KeyExchangeDeformatter.DecryptKeyExchange(Byte[]) Method

Definition

Namespace:

System.Security.Cryptography

Assemblies:

netstandard.dll, System.Security.Cryptography.dll

Source:

RSAPKCS1KeyExchangeDeformatter.cs

Extracts secret information from the encrypted key exchange data.

C#

public override byte[] DecryptKeyExchange(byte[] rgbIn);

Parameters

rgbIn

Byte[]

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

Returns

Byte[]

The secret information derived from the key exchange data.

Exceptions

CryptographicUnexpectedOperationException

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.

C#

public void Receive(byte[] iv, byte[] encryptedSessionKey, byte[] encryptedMessage)
{

    using (Aes aes = new AesCryptoServiceProvider())
    {
        aes.IV = iv;

        // Decrypt the session key
        RSAPKCS1KeyExchangeDeformatter keyDeformatter = new RSAPKCS1KeyExchangeDeformatter(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);
        }
    }
}

Remarks

You must specify a key before calling this method.

Applies to

See also

• Cryptographic Services