* Calls the method with the same name and three arguments as:
* getInstance(raw, 0, raw.length).
*
* @param raw the encoded form, excluding the header bytes.
* @return a new instance of IncomingMessage.
*/
public static IncomingMessage getInstance(byte[] raw)
{
return getInstance(raw, 0, raw.length);
}
/**
* Returns an instance of a message given its encoded contents, excluding the
* message's header bytes.
*
* @param raw the encoded form, excluding the header bytes.
* @param offset offset where to start using raw bytes from.
* @param len number of bytes to use.
* @return a new instance of IncomingMessage.
*/
public static IncomingMessage getInstance(byte[] raw, int offset, int len)
{
IncomingMessage result = new IncomingMessage();
result.in = new ByteArrayInputStream(raw, offset, len);
return result;
}
/**
* Converts two octets into the number that they represent.
*
* @param b the two octets.
* @return the length.
*/
public static int twoBytesToLength(byte[] b) throws KeyAgreementException
{
int result = (b[0] & 0xFF) << 8 | (b[1] & 0xFF);
if (result > Registry.SASL_TWO_BYTE_MAX_LIMIT)
throw new KeyAgreementException("encoded MPI size limit exceeded");
return result;
}
/**
* Converts four octets into the number that they represent.
*
* @param b the four octets.
* @return the length.
*/
public static int fourBytesToLength(byte[] b) throws KeyAgreementException
{
int result = b[0] << 24
| (b[1] & 0xFF) << 16
| (b[2] & 0xFF) << 8
| (b[3] & 0xFF);
if (result > Registry.SASL_FOUR_BYTE_MAX_LIMIT || result < 0)
throw new KeyAgreementException("encoded entity size limit exceeded");
return result;
}
public boolean hasMoreElements()
{
return (in.available() > 0);
}
/**
* Decodes a public key from the message.
*
* See {@link OutgoingMessage#writePublicKey(java.security.PublicKey)} for * more details on the internal format. * * @throws KeyAgreementException if an encoding size constraint is violated or * a mismatch was detected in the encoding. */ public PublicKey readPublicKey() throws KeyAgreementException { if (in.available() < 5) throw new KeyAgreementException("not enough bytes for a public key in message"); byte[] elementLengthBytes = new byte[4]; in.read(elementLengthBytes, 0, 4); int elementLength = fourBytesToLength(elementLengthBytes); if (in.available() < elementLength) throw new KeyAgreementException("illegal public key encoding"); int keyTypeAndFormatID = in.read() & 0xFF; elementLength--; byte[] kb = new byte[elementLength]; in.read(kb, 0, elementLength); // instantiate the right codec and decode IKeyPairCodec kpc = getKeyPairCodec(keyTypeAndFormatID); return kpc.decodePublicKey(kb); } /** * Decodes a private key from the message. *
* See {@link OutgoingMessage#writePrivateKey(java.security.PrivateKey)} for * more details. * * @throws KeyAgreementException if an encoding size constraint is violated or * a mismatch was detected in the encoding. */ public PrivateKey readPrivateKey() throws KeyAgreementException { if (in.available() < 5) throw new KeyAgreementException("not enough bytes for a private key in message"); byte[] elementLengthBytes = new byte[4]; in.read(elementLengthBytes, 0, 4); int elementLength = fourBytesToLength(elementLengthBytes); if (in.available() < elementLength) throw new KeyAgreementException("illegal private key encoding"); int keyTypeAndFormatID = in.read() & 0xFF; elementLength--; byte[] kb = new byte[elementLength]; in.read(kb, 0, elementLength); // instantiate the right codec and decode IKeyPairCodec kpc = getKeyPairCodec(keyTypeAndFormatID); return kpc.decodePrivateKey(kb); } /** * Decodes an MPI from the current message's contents. * * @return a native representation of an MPI. * @throws KeyAgreementException if an encoding exception occurs during the * operation. */ public BigInteger readMPI() throws KeyAgreementException { if (in.available() < 2) throw new KeyAgreementException("not enough bytes for an MPI in message"); byte[] elementLengthBytes = new byte[2]; in.read(elementLengthBytes, 0, 2); int elementLength = twoBytesToLength(elementLengthBytes); if (in.available() < elementLength) throw new KeyAgreementException("illegal MPI encoding"); byte[] element = new byte[elementLength]; in.read(element, 0, element.length); return new BigInteger(1, element); } public String readString() throws KeyAgreementException { if (in.available() < 2) throw new KeyAgreementException("not enough bytes for a text in message"); byte[] elementLengthBytes = new byte[2]; in.read(elementLengthBytes, 0, 2); int elementLength = twoBytesToLength(elementLengthBytes); if (in.available() < elementLength) throw new KeyAgreementException("illegal text encoding"); byte[] element = new byte[elementLength]; in.read(element, 0, element.length); String result = null; try { result = new String(element, "UTF8"); } catch (UnsupportedEncodingException x) { throw new KeyAgreementException("unxupported UTF8 encoding", x); } return result; } private IKeyPairCodec getKeyPairCodec(int keyTypeAndFormatID) throws KeyAgreementException { int keyType = (keyTypeAndFormatID >>> 4) & 0x0F; int formatID = keyTypeAndFormatID & 0x0F; switch (formatID) { case Registry.RAW_ENCODING_ID: switch (keyType) { case 0: return new DSSKeyPairRawCodec(); case 1: return new RSAKeyPairRawCodec(); case 2: return new DHKeyPairRawCodec(); case 3: return new SRPKeyPairRawCodec(); default: throw new KeyAgreementException("Unknown key-type for Raw format: " + keyType); } case Registry.X509_ENCODING_ID: switch (keyType) { case 0: return new DSSKeyPairX509Codec(); case 1: return new RSAKeyPairX509Codec(); case 2: return new DHKeyPairX509Codec(); default: throw new KeyAgreementException("Unknown key-type for X.509 format: " + keyType); } case Registry.PKCS8_ENCODING_ID: switch (keyType) { case 0: return new DSSKeyPairPKCS8Codec(); case 1: return new RSAKeyPairPKCS8Codec(); case 2: return new DHKeyPairPKCS8Codec(); default: throw new KeyAgreementException("Unknown key-type for PKCS#8 format: " + keyType); } default: throw new KeyAgreementException("Unknown format identifier: " + formatID); } } }