messageProcessor
Class Recoder

java.lang.Object
  messageProcessor.Recoder

final class Recoder
extends java.lang.Object

Recodes (decrypts/encrypts) messages. Prevents linkability of (incoming and outgoing) messages due to their appearance.

This class is thread-safe (but parallel execution of a single instance's methods won't increase performance. For parallel processing, several Recoders are needed).

Author:

Karl-Peter Fuchs

Field Summary

private javax.crypto.Cipher	asymmetricCipher Cipher for asymmetric cryptography.
private static InternalInformationPortController	internalInformationPort Reference on InternalInformationPort.
private java.security.KeyPair	KEY_PAIR Public and private key of the asymmetric crypto system.
private static java.util.logging.Logger	LOGGER Logger used to log and display information.

Constructor Summary

protected	Recoder() Constructor used to generate a Recoder used to encrypt replies.
protected	Recoder(java.security.KeyPair keyPair) Constructor used to generate a Recoder used to decrypt requests.

Method Summary

protected byte[]	decrypt(byte[] data, java.lang.String transformation) Decrypts the bypassed data using the internal asymmetric cipher (and private key) and the specified transformation.
private ChannelEstablishMessage	decrypt(ChannelEstablishMessage message) Decrypts the hybridly encrypted, bypassed ChannelEstablishMessage.
private ChannelMessage	decrypt(ChannelMessage message) Decrypts the symmetrically encrypted, bypassed ChannelMessage.
private ReplyMessage	encrypt(ReplyMessage message) Encrypts the bypassed ReplyMessage.
protected java.security.Key	getPublicKey() Returns the public key of this Recoder.
private void	initializeCiphersForUser(User channel, ChannelEstablishMessage message) Initializes the ciphers used to recode messages for the bypassed user/channel.
protected Message	recode(BasicMessage message) Recodes (decrypts/encrypts) the bypassed message according to its type.

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 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.

KEY_PAIR

private final java.security.KeyPair KEY_PAIR

Public and private key of the asymmetric crypto system.

asymmetricCipher

private javax.crypto.Cipher asymmetricCipher

Cipher for asymmetric cryptography.

Constructor Detail

Recoder

protected Recoder(java.security.KeyPair keyPair)

Constructor used to generate a Recoder used to decrypt requests.

Creates a new Recoder which will use the bypassed KeyPair to decrypt messages.

Instantiates Cipher objects for later use as specified in the property file.

Parameters:

keyPair - Public and private key of the asymmetric crypto system.

Recoder

protected Recoder()

Constructor used to generate a Recoder used to encrypt replies.

Method Detail

getPublicKey

protected java.security.Key getPublicKey()

Returns the public key of this Recoder.

Returns:

The public key of this Recoder.

recode

protected Message recode(BasicMessage message)

Recodes (decrypts/encrypts) the bypassed message according to its type.

Parameters:

message - The message to be recoded.

Returns:

The recoded message (same reference as previously bypassed). "Null", if recoding failed.

decrypt

private ChannelEstablishMessage decrypt(ChannelEstablishMessage message)

Decrypts the hybridly encrypted, bypassed ChannelEstablishMessage.

Parameters:

message - The message to be decrypted.

Returns:

The decrypted message (same reference as previously bypassed). null, if recoding failed.

decrypt

private ChannelMessage decrypt(ChannelMessage message)

Decrypts the symmetrically encrypted, bypassed ChannelMessage.

Parameters:

message - The message to be decrypted.

Returns:

The decrypted message (same reference as previously bypassed). null, if recoding failed.

encrypt

private ReplyMessage encrypt(ReplyMessage message)

Encrypts the bypassed ReplyMessage.

Parameters:

message - The message to be encrypted.

Returns:

The encrypted message (same reference as previously bypassed). null, if recoding failed.

initializeCiphersForUser

private void initializeCiphersForUser(User channel,
                                      ChannelEstablishMessage message)
                               throws java.lang.Exception

Initializes the ciphers used to recode messages for the bypassed user/channel.

Parameters:

channel - User/channel the ciphers shall be initialized for.

message - Message containing the data needed to initialize the ciphers (session key and initialization vector).

Throws:

java.lang.Exception - If the initialization process fails.

decrypt

protected byte[] decrypt(byte[] data,
                         java.lang.String transformation)
                  throws java.lang.Exception

Decrypts the bypassed data using the internal asymmetric cipher (and private key) and the specified transformation.

Parameters:

data - Data to be decrypted.

transformation - Transformation that shall be used for decryption.

Returns:

Decrypted data.

Throws:

java.lang.Exception - Any type of error preventing the data from being decrypted.