ptolemy.actor.lib.security
Class SignatureActor

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.actor.AtomicActor
                      ptolemy.actor.TypedAtomicActor
                          ptolemy.actor.lib.security.SignatureActor

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable

Direct Known Subclasses:

SignatureSigner, SignatureVerifier

public class SignatureActor
extends TypedAtomicActor

A common base class for actors that use cryptographic signatures.

In cryptography, digital signatures can be used to verify that the data was not modified in transit. However, the data itself is passed in clear text.

The signature algorithms that maybe implemented are limited to the signature algorithms that are implemented by providers following the JCE specifications and installed on the machine being run. In case a provider specific instance of an algorithm is needed, the provider may also be specified in the provider parameter.

The input and output are both arrays of unsigned bytes.

In initialize(), this actor sets the value of the _signature member to the results of calling java.security.Signature.getInstance() with the values of the signatureAlgorithm and provider parameters. Derived classes should have a fire() method that uses the _signature member to process data appropriately. In the fire() method of the derived class, super.fire() should be called before accessing _signature so that _signature may be updated if the attributes changed.

This actor relies on the Java Cryptography Architecture (JCA) and Java Cryptography Extension (JCE). See the CryptographyActor documentation for resources about JCA and JCE.

Since:

Ptolemy II 4.0

Version:

$Id: SignatureActor.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Christopher Hylands Brooks, Contributor: Rakesh Reddy

See Also:

Serialized Form

Accepted Rating:

Red (cxh)

Proposed Rating:

Yellow (cxh)

Nested Class Summary

Nested classes/interfaces inherited from class ptolemy.kernel.Entity

Entity.ContainedObjectsIterator

Field Summary

protected java.lang.String	_provider The name of the provider to be used for a provider specific implementation.
protected java.security.Signature	_signature The signature that will be used to process the data.
protected java.lang.String	_signatureAlgorithm The name of the signature algorithm to be used.
private boolean	_updateSignatureNeeded
TypedIOPort	input This port takes in an unsigned byte array and processes the data.
TypedIOPort	output This port sends out the processed data received from input in the form of an unsigned byte array.
StringParameter	provider Specify a provider for the given algorithm.
StringParameter	signatureAlgorithm Specify the algorithm to be used to sign data.

Fields inherited from class ptolemy.actor.AtomicActor

_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested

Fields inherited from class ptolemy.kernel.util.NamedObj

_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKS

Fields inherited from interface ptolemy.actor.Executable

COMPLETED, NOT_READY, STOP_ITERATING

Constructor Summary

SignatureActor(CompositeEntity container, java.lang.String name)
Construct an actor with the given container and name.

Method Summary

private void	_updateSignature() If necessary, the value of _signature is updated by calling Signature.getInstance() with an argument that is created from the values of the _signatureAlgorithm and _provider
void	attributeChanged(Attribute attribute) Override the base class to reinitialize the state if the the signatureAlgorithm, or provider parameter is changed.
void	fire() Update _signature if an attribute has changed and then invoke super.fire() to transform the input data.
void	initialize() Use the values of the signatureAlgorithm and provider parameters to initialize the java.security.Signature object.

Methods inherited from class ptolemy.actor.TypedAtomicActor

_addPort, _fireAt, _fireAt, attributeTypeChanged, clone, newPort, typeConstraintList, typeConstraints

Methods inherited from class ptolemy.actor.AtomicActor

_actorFiring, _actorFiring, addActorFiringListener, addInitializable, clone, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, postfire, prefire, preinitialize, pruneDependencies, recordFiring, removeActorFiringListener, removeDependency, removeInitializable, setContainer, stop, stopFire, terminate, wrapup

Methods inherited from class ptolemy.kernel.ComponentEntity

_adjustDeferrals, _checkContainer, _getContainedObject, _propagateExistence, getContainer, instantiate, isAtomic, isOpaque, moveDown, moveToFirst, moveToIndex, moveToLast, moveUp, propagateExistence, setName

Methods inherited from class ptolemy.kernel.Entity

_description, _exportMoMLContents, _removePort, _validateSettables, connectedPortList, connectedPorts, containedObjectsIterator, getAttribute, getPort, getPorts, linkedRelationList, linkedRelations, portList, removeAllPorts, setClassDefinition, uniqueName

Methods inherited from class ptolemy.kernel.InstantiableNamedObj

_setParent, exportMoML, getChildren, getElementName, getParent, getPrototypeList, isClassDefinition, isWithinClassDefinition

Methods inherited from class ptolemy.kernel.util.NamedObj

_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _debug, _debug, _debug, _debug, _debug, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _propagateValue, _recordDecoratedAttributes, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, attributeList, attributeList, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getFullName, getModelErrorHandler, getName, getName, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, propagateValue, propagateValues, removeChangeListener, removeDebugListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, toString, validateSettables, workspace

Methods inherited from class java.lang.Object

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

Methods inherited from interface ptolemy.actor.Actor

createReceivers, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, newReceiver, outputPortList

Methods inherited from interface ptolemy.actor.Executable

isFireFunctional, isStrict, iterate, postfire, prefire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, preinitialize, removeInitializable, wrapup

Methods inherited from interface ptolemy.kernel.util.Nameable

description, getContainer, getDisplayName, getFullName, getName, getName, setName

Methods inherited from interface ptolemy.kernel.util.Derivable

getDerivedLevel, getDerivedList, propagateValue

Field Detail

input

public TypedIOPort input

This port takes in an unsigned byte array and processes the data.

output

public TypedIOPort output

This port sends out the processed data received from input in the form of an unsigned byte array.

provider

public StringParameter provider

Specify a provider for the given algorithm. Takes the algorithm name as a string. The default value is "SystemDefault" which allows the system chooses the provider based on the JCE architecture.

signatureAlgorithm

public StringParameter signatureAlgorithm

Specify the algorithm to be used to sign data. The algorithm is specified as a string. The algorithms are limited to those implemented by providers using the Java JCE which are found on the system. Depending on your JDK installation, possible values might be SHA1WITHDSA or MD5WITHRSA. The initial default is the first value returned by java.security.Security.getAlgorithms("Signature").

_provider

protected java.lang.String _provider

The name of the provider to be used for a provider specific implementation.

_signature

protected java.security.Signature _signature

The signature that will be used to process the data.

_signatureAlgorithm

protected java.lang.String _signatureAlgorithm

The name of the signature algorithm to be used.

_updateSignatureNeeded

private boolean _updateSignatureNeeded

Constructor Detail

SignatureActor

public SignatureActor(CompositeEntity container,
                      java.lang.String name)
               throws NameDuplicationException,
                      IllegalActionException

Construct an actor with the given container and name. The Java virtual machine is queried for algorithm and provider choices and these choices are added to the appropriate parameters.

Parameters:

container - The container.

name - The name of this actor.

Throws:

IllegalActionException - If the actor cannot be contained by the proposed container.

NameDuplicationException - If the container already has an actor with this name.

Method Detail

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

Override the base class to reinitialize the state if the the signatureAlgorithm, or provider parameter is changed.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - Not thrown in this base class.

fire

public void fire()
          throws IllegalActionException

Update _signature if an attribute has changed and then invoke super.fire() to transform the input data.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor

Throws:

IllegalActionException - If thrown by the base class or if there is a problem processing the data.

initialize

public void initialize()
                throws IllegalActionException

Use the values of the signatureAlgorithm and provider parameters to initialize the java.security.Signature object. If provider is "SystemDefault" then the system chooses the provider based on the JCE.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If the base class throws it, if the algorithm is not found, or if the specified provider does not exist.

_updateSignature

private void _updateSignature()
                       throws IllegalActionException

If necessary, the value of _signature is updated by calling Signature.getInstance() with an argument that is created from the values of the _signatureAlgorithm and _provider

Throws:

IllegalActionException