message
Class ChannelMessage

java.lang.Object
  message.Message
      message.ChannelMessage

All Implemented Interfaces:

java.lang.Comparable<Message>, BasicMessage, ExternalMessage, Request

public final class ChannelMessage
extends Message
implements Request, ExternalMessage

ExternalMessage used to transmit data on an existing channel. The parts this message consists of are defined in the enumeration ChannelMessagePart. A pair of set and get methods is present for each defined part.

Author:

Karl-Peter Fuchs

Field Summary

static byte	IDENTIFIER Identifier for this type of message.
private static InternalInformationPortController	internalInformationPort Reference on component InternalInformationPort.
private static java.util.logging.Logger	LOGGER Logger used to log and display information.
private int	NUMBER_OF_FURTHER_HOPS Number of further hops (= mixes), this message must pass to reach its destination.

Constructor Summary

ChannelMessage(byte[] byteMesssage, int numberOfFurtherHops)
Message constructor used by client.

ChannelMessage(byte[] byteMesssage, User channel, int numberOfFurtherHops)
Message constructor used by a mix.

Method Summary

byte[]	getMAC() Returns the MessagePart MAC = The Message Authentication Code (MAC) of this message.
int	getMessageID() Returns the MessagePart MESSAGE_ID = An identifieing number, which is the same for every envelope of a mix message.
private byte[]	getPart(ChannelMessagePart messagePart) Returns a byte representation of a MessagePart.
Payload	getPayload() Returns the MessagePart PAYLOAD.
byte[]	getSignedData() Returns the MessagePart SIGNED_DATA.
void	setMAC(byte[] mac) Sets the MessagePart MAC to the bypassed value.
void	setMessageID(int newID) Sets the MessagePart MESSAGE_ID to the bypassed value.
private void	setPart(ChannelMessagePart messagePart, byte[] data) Saves a byte representation of a MessagePart.
void	setPayload(Payload newPayload) Sets the MessagePart PAYLOAD to the bypassed value.
void	setSignedData(byte[] newSignedData) Sets the MessagePart SIGNED_DATA to the bypassed value.
java.lang.String	toString() Returns a simple String representation of this class featuring several message parts.

Methods inherited from class message.Message

compareTo, getByteMessage, getChannel, getChannelID, getNextMixChannelID, getTimeOfReceival, setByteMessage, setPayloadRange, setTimeOfReceival

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface message.BasicMessage

getByteMessage, getChannel, getChannelID, getNextMixChannelID, getTimeOfReceival, setByteMessage, setPayloadRange, setTimeOfReceival

Field Detail

internalInformationPort

private static InternalInformationPortController internalInformationPort

Reference on component InternalInformationPort. Used to display and/or log data and read general settings.

LOGGER

private static final java.util.logging.Logger LOGGER

Logger used to log and display information.

IDENTIFIER

public static final byte IDENTIFIER

Identifier for this type of message. Necessary since messages are transmitted as byte streams which don't support the instanceOf operator.

See Also:

Constant Field Values

NUMBER_OF_FURTHER_HOPS

private final int NUMBER_OF_FURTHER_HOPS

Number of further hops (= mixes), this message must pass to reach its destination. Used to find a MessagePart's position in the byteMessage which has (a) dynamic start- and/or end-position(s). Note: Message length isn't constant in a cascade.

See Also:

Message.byteMessage, ChannelEstablishMessagePart

Constructor Detail

ChannelMessage

public ChannelMessage(byte[] byteMesssage,
                      User channel,
                      int numberOfFurtherHops)

Message constructor used by a mix.

Constructs a new ChannelMessage with the submitted content (byteMesssage) for the specified user/channel.

Parameters:

byteMesssage - Byte representation of the message (as received from the client/previous mix).

channel - User/channel the message shall be created for.

numberOfFurtherHops - Number of further hops (= mixes), this message must pass.

ChannelMessage

public ChannelMessage(byte[] byteMesssage,
                      int numberOfFurtherHops)

Message constructor used by client.

Constructs a new ChannelMessage with the submitted content (byteMesssage).

Parameters:

byteMesssage - Byte representation of the message (can be empty).

numberOfFurtherHops - Number of mixes in the cascade.

Method Detail

getMAC

public byte[] getMAC()

Returns the MessagePart MAC = The Message Authentication Code (MAC) of this message.

Returns:

MessagePart MAC.

See Also:

ChannelMessagePart, ChannelMessagePart.MAC

setMAC

public void setMAC(byte[] mac)
            throws MessagePartHasWrongSizeException

Sets the MessagePart MAC to the bypassed value.

Parameters:

mac - The Message Authentication Code (MAC) of this message.

Throws:

MessagePartHasWrongSizeException

See Also:

ChannelMessagePart, ChannelMessagePart.MAC

getMessageID

public int getMessageID()

Returns the MessagePart MESSAGE_ID = An identifieing number, which is the same for every envelope of a mix message. Used to trace messages for debugging. Can only be read correctly, when current envelope is decrypted! Note: For testing only (MAKES MIX INSECURE)!

Specified by:

getMessageID in interface BasicMessage

Overrides:

getMessageID in class Message

Returns:

MessagePart MESSAGE_ID.

See Also:

ChannelMessagePart, ChannelMessagePart.MESSAGE_ID

setMessageID

public void setMessageID(int newID)

Sets the MessagePart MESSAGE_ID to the bypassed value.

Specified by:

setMessageID in interface BasicMessage

Overrides:

setMessageID in class Message

Parameters:

newID - An identifieing number, which is the same for every envelope of a mix message. Used to trace messages for debugging. Can only be set correctly, when current envelope is decrypted! Note: For testing only (MAKES MIX INSECURE)!

See Also:

ChannelMessagePart, ChannelMessagePart.MESSAGE_ID

getPayload

public Payload getPayload()

Returns the MessagePart PAYLOAD.

Returns:

MessagePart PAYLOAD.

See Also:

ChannelMessagePart, ChannelMessagePart.PAYLOAD

setPayload

public void setPayload(Payload newPayload)
                throws MessagePartHasWrongSizeException

Sets the MessagePart PAYLOAD to the bypassed value.

Parameters:

newPayload - Payload to be set.

Throws:

MessagePartHasWrongSizeException

See Also:

ChannelMessagePart, ChannelMessagePart.PAYLOAD

getSignedData

public byte[] getSignedData()

Returns the MessagePart SIGNED_DATA.

Returns:

MessagePart SIGNED_DATA.

See Also:

ChannelMessagePart, ChannelMessagePart.SIGNED_DATA

setSignedData

public void setSignedData(byte[] newSignedData)
                   throws MessagePartHasWrongSizeException

Sets the MessagePart SIGNED_DATA to the bypassed value.

Parameters:

newSignedData - The signed data to be set.

Throws:

MessagePartHasWrongSizeException

See Also:

ChannelMessagePart, ChannelMessagePart.SIGNED_DATA

getPart

private byte[] getPart(ChannelMessagePart messagePart)

Returns a byte representation of a MessagePart. Example of usage: getPart(ChannelMessagePart.NAME_OF_ENUM_CONSTANT);

Parameters:

messagePart - Enum constant who's byte representation shall be retrieved (= "type" of the part).

Returns:

Byte representation of the MessagePart suiting the bypassed enum constant.

See Also:

ChannelMessagePart

setPart

private void setPart(ChannelMessagePart messagePart,
                     byte[] data)
              throws MessagePartHasWrongSizeException

Saves a byte representation of a MessagePart. Example of usage: setPart(ChannelMessagePart.NAME_OF_ENUM_CONSTANT, data);

Parameters:

messagePart - Enum constant who's byte representation shall be saved.

data - Byte representation of the MessagePart to be saved.

Throws:

MessagePartHasWrongSizeException - Thrown when a MessagePart that shall be assigned is of wrong size.

See Also:

ChannelMessagePart

toString

public java.lang.String toString()

Returns a simple String representation of this class featuring several message parts. Note: Output is only correct for decrypted messages.

Overrides:

toString in class java.lang.Object

Returns:

A simple String representation of this class featuring several message parts