package gnu.crypto.key;
// ----------------------------------------------------------------------------
// $Id: OutgoingMessage.java,v 1.2 2005/10/06 04:24:16 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module. An independent module is a module which is
// not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so. If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import gnu.crypto.Registry;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.math.BigInteger;
/**
* <p>An implementation of outgoing messages for use with key agreement
* protocols.</p>
*
* @version $Revision: 1.2 $
*/
public class OutgoingMessage {
// Constants and variables
// -------------------------------------------------------------------------
/** The internal output stream. */
private ByteArrayOutputStream out;
// Constructor(s)
// -------------------------------------------------------------------------
public OutgoingMessage() {
super();
out = new ByteArrayOutputStream();
}
// Class methods
// -------------------------------------------------------------------------
// Instance methods
// -------------------------------------------------------------------------
/**
* <p>Returns the encoded form of the current message including the 4-byte
* length header.</p>
*
* @throws KeyAgreementException if an encoding size constraint is violated.
*/
public byte[] toByteArray() throws KeyAgreementException {
byte[] buffer = wrap();
int length = buffer.length;
byte[] result = new byte[length+4];
result[0] = (byte)(length >>> 24);
result[1] = (byte)(length >>> 16);
result[2] = (byte)(length >>> 8);
result[3] = (byte) length;
System.arraycopy(buffer, 0, result, 4, length);
return result;
}
/**
* <p>Returns the encoded form of the current message excluding the 4-byte
* length header.</p>
*
* @throws KeyAgreementException if an encoding size constraint is violated.
*/
public byte[] wrap() throws KeyAgreementException {
int length = out.size();
if (length > Registry.SASL_BUFFER_MAX_LIMIT || length < 0) {
throw new KeyAgreementException("message content is too long");
}
return out.toByteArray();
}
/**
* <p>Encodes a public key into the message.</p>
*
* @param k the public key to encode.
* @throws KeyAgreementException if an encoding size constraint is violated.
*/
public void writePublicKey(PublicKey k) throws KeyAgreementException {
IKeyPairCodec kpc = KeyPairCodecFactory.getInstance(k);
if (kpc == null) {
throw new KeyAgreementException("");
}
byte[] b = kpc.encodePublicKey(k);
int length = b.length;
if (length > Registry.SASL_FOUR_BYTE_MAX_LIMIT) {
throw new KeyAgreementException("encoded public key is too long");
}
byte[] lengthBytes = {
(byte)(length >>> 24),
(byte)(length >>> 16),
(byte)(length >>> 8),
(byte) length
};
out.write(lengthBytes, 0, 4);
out.write(b, 0, b.length);
}
/**
* <p>Encodes a private key into the message.</p>
*
* @param k the private key to encode.
* @throws KeyAgreementException if an encoding size constraint is violated.
*/
public void writePrivateKey(PrivateKey k) throws KeyAgreementException {
IKeyPairCodec kpc = KeyPairCodecFactory.getInstance(k);
if (kpc == null) {
throw new KeyAgreementException("");
}
byte[] b = kpc.encodePrivateKey(k);
int length = b.length;
if (length > Registry.SASL_FOUR_BYTE_MAX_LIMIT) {
throw new KeyAgreementException("encoded private key is too long");
}
byte[] lengthBytes = {
(byte)(length >>> 24),
(byte)(length >>> 16),
(byte)(length >>> 8),
(byte) length
};
out.write(lengthBytes, 0, 4);
out.write(b, 0, b.length);
}
/**
* <p>Encodes an MPI into the message.</p>
*
* @param val the MPI to encode.
* @throws KeyAgreementException if an encoding size constraint is violated.
*/
public void writeMPI(BigInteger val) throws KeyAgreementException {
byte[] b = val.toByteArray();
int length = b.length;
if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT) {
throw new KeyAgreementException("MPI is too long");
}
byte[] lengthBytes = { (byte)(length >>> 8), (byte) length };
out.write(lengthBytes, 0, 2);
out.write(b, 0, b.length);
}
/**
* <p>Encodes a string into the message.</p>
*
* @param s the string to encode.
* @throws KeyAgreementException if the UTF8 encoding is not supported on
* this platform, or if an encoding size constraint is violated.
*/
public void writeString(String s) throws KeyAgreementException {
byte[] b = null;
try {
b = s.getBytes("UTF8");
} catch (UnsupportedEncodingException x) {
throw new KeyAgreementException("unxupported UTF8 encoding", x);
}
int length = b.length;
if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT) {
throw new KeyAgreementException("text too long");
}
byte[] lengthBytes = { (byte)(length >>> 8), (byte) length };
out.write(lengthBytes, 0, 2);
out.write(b, 0, b.length);
}
}