client
Class MessageGenerator

java.lang.Object
  client.MessageGenerator

final class MessageGenerator
extends java.lang.Object

Provides methods for generating messages (the mixes are capable of processing) from byte arrays.

Author:

Karl-Peter Fuchs

Field Summary

private static NetworkClockController	clock Reference on component NetworkClock.
private Cryptography	cryptography Used to encrypt messages.
private static InternalInformationPortController	internalInformationPort Reference on component InternalInformationPortController.
private static java.util.logging.Logger	LOGGER Logger used to log and display information.
private java.security.Key[]	macKeys Keys for message authentication codes (MACs).
private int	NUMBER_OF_MIXES_IN_CASCADE Number of mixes in the cascade.

Constructor Summary

protected

MessageGenerator(int numberOfMixesInCascade, Cryptography cryptography) Generates a new MessageGenerator for generating messages (the mixes are capable of processing) from byte arrays.

Method Summary

protected byte[]	generateChannelEstablishMessage(byte[] bytePayload) Generates a message which consists of one or more (encrypted) layers, the cascade's mixes are capable of processing from the bypassed data (Type: ChannelEstablishMessage).
protected byte[]	generateChannelMessage(byte[] bytePayload) Generates a message which consists of one or more (encrypted) layers, the cascade's mixes are capable of processing from the bypassed data (Type: ChannelMessage).
private Message	generatePlaintextChannelEstablishMessage(int positionOfMixInCascade, Payload payload, int messageID) Generates a new (plaintext) ChannelEstablishMessage for the specified mix.
private Message	generatePlaintextChannelMessage(int positionOfMixInCascade, Payload payload, int messageID) Generates a new (plaintext) ChannelMessage for the specified mix.

Methods inherited from class java.lang.Object

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

Field Detail

internalInformationPort

private static InternalInformationPortController internalInformationPort

Reference on component InternalInformationPortController. 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.

clock

private static NetworkClockController clock

Reference on component NetworkClock.

NUMBER_OF_MIXES_IN_CASCADE

private final int NUMBER_OF_MIXES_IN_CASCADE

Number of mixes in the cascade.

cryptography

private Cryptography cryptography

Used to encrypt messages.

macKeys

private java.security.Key[] macKeys

Keys for message authentication codes (MACs).

Constructor Detail

MessageGenerator

protected MessageGenerator(int numberOfMixesInCascade,
                           Cryptography cryptography)

Generates a new MessageGenerator for generating messages (the mixes are capable of processing) from byte arrays.

Parameters:

numberOfMixesInCascade - Number of mixes in the cascade this Client shall use.

cryptography - Reference on Cryptography object that shall be used to encrypt messages.

Method Detail

generateChannelEstablishMessage

protected byte[] generateChannelEstablishMessage(byte[] bytePayload)
                                          throws MessageTooLongException

Generates a message which consists of one or more (encrypted) layers, the cascade's mixes are capable of processing from the bypassed data (Type: ChannelEstablishMessage). A layer is added for each mix in the cascade.

Parameters:

bytePayload - Data to generate the mix message from.

Returns:

The generated ChannelEstablishMessage as a byte array.

Throws:

MessageTooLongException - Thrown when the bypassed message is larger than the maximum message size.

generateChannelMessage

protected byte[] generateChannelMessage(byte[] bytePayload)
                                 throws MessageTooLongException

Generates a message which consists of one or more (encrypted) layers, the cascade's mixes are capable of processing from the bypassed data (Type: ChannelMessage). A layer is added for each mix in the cascade.

Parameters:

bytePayload - Data to generate the mix message from.

Returns:

The generated ChannelMessage as a byte array.

Throws:

MessageTooLongException - Thrown when the bypassed message is larger than the maximum message size.

generatePlaintextChannelEstablishMessage

private Message generatePlaintextChannelEstablishMessage(int positionOfMixInCascade,
                                                         Payload payload,
                                                         int messageID)

Generates a new (plaintext) ChannelEstablishMessage for the specified mix. Generates message header and authentication information as well.

Parameters:

positionOfMixInCascade - The mix' position in the cascade, the plaintext message shall be created for.

payload - Payload to be embedded.

messageID - Note: For testing only (MAKES MIX INSECURE): An identifieing number, which is the same for every envelope of a mix message. Used to trace messages for debugging.

Returns:

The generated (plaintext) message.

generatePlaintextChannelMessage

private Message generatePlaintextChannelMessage(int positionOfMixInCascade,
                                                Payload payload,
                                                int messageID)

Generates a new (plaintext) ChannelMessage for the specified mix. Generates message header and authentication information as well.

Parameters:

positionOfMixInCascade - The mix' position in the cascade, the plaintext message shall be created for.

payload - Payload to be embedded.

messageID - Note: For testing only (MAKES MIX INSECURE): An identifieing number, which is the same for every envelope of a mix message. Used to trace messages for debugging.

Returns:

The generated (plaintext) message.