mono/mcs/class/corlib/System.Security.Cryptography/RSAPKCS1KeyExchangeFormatter.cs

//
// RSAPKCS1KeyExchangeFormatter.cs: Handles PKCS#1 v.1.5 keyex encryption.
//
// Author:
//	Sebastien Pouliot ([email protected])
//
// (C) 2002 Motus Technologies Inc. (http://www.motus.com)
//

using System;
using System.Security.Cryptography;

namespace System.Security.Cryptography
{

// LAMESPEC: There seems no way to select a hash algorithm. The default 
// algorithm, is SHA1 because the class use the PKCS1MaskGenerationMethod -
// which default to SHA1.
public class RSAPKCS1KeyExchangeFormatter: AsymmetricKeyExchangeFormatter
{
	private RSA rsa;
	private RandomNumberGenerator random;

	public RSAPKCS1KeyExchangeFormatter ()
	{
	}

	public RSAPKCS1KeyExchangeFormatter (AsymmetricAlgorithm key)
	{
		SetKey (key);
	}

	public RandomNumberGenerator Rng 
	{
		get { return random; }
		set { random = value; }
	}

	public override string Parameters 
	{
		get { return "<enc:KeyEncryptionMethod enc:Algorithm=\"http://www.microsoft.com/xml/security/algorithm/PKCS1-v1.5-KeyEx\" xmlns:enc=\"http://www.microsoft.com/xml/security/encryption/v1.0\" />"; }
	}

	public override byte[] CreateKeyExchange (byte[] rgbData)
	{
		if (rsa == null)
			throw new CryptographicException ();
		if (random == null)
			random = RandomNumberGenerator.Create ();  // create default
		return PKCS1.Encrypt_v15 (rsa, random, rgbData);
	}

	public override byte[] CreateKeyExchange (byte[] rgbData, Type symAlgType)
	{
		// documentation says that symAlgType is not used !?!
		// FIXME: must be the same as previous method ?
		return CreateKeyExchange (rgbData);
	}

	public override void SetKey (AsymmetricAlgorithm key)
	{
		if (key != null) {
			if (key is RSA) {
				rsa = (RSA)key;
			}
			else
				throw new InvalidCastException ();
		}
		// here null is accepted!
	}
}

}