org.jgroups.protocols

Class ENCRYPT


public class ENCRYPT
extends Protocol

ENCRYPT layer. Encrypt and decrypt the group communication in JGroups The file can be used in two ways:

Each message is identified as encrypted with a specific encryption header which identifies the type of encrypt header and an MD5 digest that identifies the version of the key being used to encrypt/decrypt the messages.

Option 1


This is the simplest option and can be used by simply inserting the Encryption layer at any point in the JGroup stack - it will encrypt all Events of a type MSG that have a non-null message buffer. The format of the entry in this form is:
<ENCRYPT key_store_name="defaultStore.keystore" store_password="changeit" alias="myKey"/>
An example bare-bones.xml file showing the keystore version can be found in the conf ina file called EncryptKeyStore.xml - along with a defaultStore.keystore file.
In order to use the Encrypt layer in this manner it is necessary to have the secretKey already generated in a keystore file. The directory containing the keystore file must be on the application's classpath. You cannot create a SecretKey keystore file using the keytool application shipped with the JDK. A java file called KeyStoreGenerator is included in the demo package that can be used from the command line (or IDE) to generate a suitable keystore.

Option 2


This option is suited to an application that does not ship with a known key but instead it is generated and distributed by the controller. The secret key is first generated by the Controller (in JGroup terms). When a view change occurs a peer will request the secret key by sending a key request with its own public key. The controller encrypts the secret key with this key and sends it back to the peer who then decrypts it and installs the key as its own secret key.
All encryption and decryption of Messages is done using this key. When a peer receives a view change that shows a different keyserver it will repeat this process - the view change event also trigger the encrypt layer to queue up and down messages until the new key is installed. The previous keys are retained so that messages sent before the view change that are queued can be decrypted if the key is different.
An example EncryptNoKeyStore.xml is included in the conf file as a guide.


Note: the current version does not support the concept of perfect forward encryption (PFE) which means that if a peer leaves the group the keys are re-generated preventing the departed peer from decrypting future messages if it chooses to listen in on the group. This is not included as it really requires a suitable authentication scheme as well to make this feature useful as there is nothing to stop the peer rejoining and receiving the new key. A future release will address this issue.

Author:
Steve Woodcock

Nested Class Summary

static class
ENCRYPT.EncryptHeader

Field Summary

Fields inherited from class org.jgroups.stack.Protocol

down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, stats, trace, up_handler, up_prot, up_queue, up_thread, up_thread_prio, warn

Constructor Summary

ENCRYPT()

Method Summary

void
down(Event evt)
An event is to be sent down the stack.
protected String
getAsymAlgorithm()
protected Cipher
getAsymCipher()
protected int
getAsymInit()
protected String
getAsymProvider()
protected SecretKey
getDesKey()
protected Address
getKeyServerAddr()
protected String
getKeyStoreName()
protected KeyPair
getKpair()
protected Address
getLocal_addr()
String
getName()
protected PublicKey
getServerPubKey()
protected String
getSymAlgorithm()
protected Cipher
getSymDecodingCipher()
protected Cipher
getSymEncodingCipher()
protected int
getSymInit()
protected String
getSymProvider()
void
init()
Called after instance has been created (null constructor) and before protocol is started.
void
initKeyPair()
Generates the public/private key pair from the init params
void
initSymKey()
Used to initialise the symmetric key if none is supplied in a keystore.
void
reset()
Just remove if you don't need to reset any state
protected void
setKeyServerAddr(Address keyServerAddr)
protected void
setLocal_addr(Address local_addr)
boolean
setProperties(Properties props)
Configures the protocol initially.
void
up(Event evt)
An event was received from the layer below.

Methods inherited from class org.jgroups.stack.Protocol

destroy, down, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getName, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, isTrace, isWarn, passDown, passUp, printStats, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, resetStats, setDownProtocol, setObserver, setProperties, setPropertiesInternal, setProtocolStack, setTrace, setUpProtocol, setWarn, start, startDownHandler, startUpHandler, statsEnabled, stop, stopInternal, up, upThreadEnabled

Constructor Details

ENCRYPT

public ENCRYPT()

Method Details

down

public void down(Event evt)
An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using passDown(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using passUp().
Overrides:
down in interface Protocol

getAsymAlgorithm

protected String getAsymAlgorithm()
Returns:
Returns the asymAlgorithm.

getAsymCipher

protected Cipher getAsymCipher()
Returns:
Returns the asymCipher.

getAsymInit

protected int getAsymInit()
Returns:
Returns the asymInit.

getAsymProvider

protected String getAsymProvider()
Returns:
Returns the asymProvider.

getDesKey

protected SecretKey getDesKey()
Returns:
Returns the desKey.

getKeyServerAddr

protected Address getKeyServerAddr()
Returns:
Returns the keyServerAddr.

getKeyStoreName

protected String getKeyStoreName()
Returns:
Returns the keyStoreName.

getKpair

protected KeyPair getKpair()
Returns:
Returns the kpair.

getLocal_addr

protected Address getLocal_addr()
Returns:
Returns the local_addr.

getName

public String getName()
Overrides:
getName in interface Protocol

getServerPubKey

protected PublicKey getServerPubKey()
Returns:
Returns the serverPubKey.

getSymAlgorithm

protected String getSymAlgorithm()
Returns:
Returns the symAlgorithm.

getSymDecodingCipher

protected Cipher getSymDecodingCipher()
Returns:
Returns the symDecodingCipher.

getSymEncodingCipher

protected Cipher getSymEncodingCipher()
Returns:
Returns the symEncodingCipher.

getSymInit

protected int getSymInit()
Returns:
Returns the symInit.

getSymProvider

protected String getSymProvider()
Returns:
Returns the symProvider.

init

public void init()
            throws Exception
Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
Overrides:
init in interface Protocol

initKeyPair

public void initKeyPair()
            throws Exception
Generates the public/private key pair from the init params

initSymKey

public void initSymKey()
            throws Exception
Used to initialise the symmetric key if none is supplied in a keystore.

reset

public void reset()
Just remove if you don't need to reset any state

setKeyServerAddr

protected void setKeyServerAddr(Address keyServerAddr)
Parameters:
keyServerAddr - The keyServerAddr to set.

setLocal_addr

protected void setLocal_addr(Address local_addr)
Parameters:
local_addr - The local_addr to set.

setProperties

public boolean setProperties(Properties props)
Configures the protocol initially. A configuration string consists of name=value items, separated by a ';' (semicolon), e.g.:
 "loopback=false;unicast_inport=4444"
 
Overrides:
setProperties in interface Protocol

up

public void up(Event evt)
An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack using passDown() or c) the event (or another event) is sent up the stack using passUp().
Overrides:
up in interface Protocol

Copyright B) 1998-2005 Bela Ban. All Rights Reserved.