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ch.ethz.prose
Class SignedAspect  

java.lang.Object
  ch.ethz.prose.Aspect
      ch.ethz.prose.SignedAspect

All Implemented Interfaces:

Insertable, java.io.Serializable

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public final class SignedAspect

extends Aspect

Class SignedAspect is a wrapper for an Aspect contained in a SignedObject. Thus it is possible to verify the signer of the extension before it is used. For security reason, this class is (and has to be) declared final

At construction, the public and private keys passed as KeyPair are not checked for being a valid pair and the private key is not stored for later use. Only an explicit call to verifyExtension does check the public key stored. The signing algorithm to use is deduced by the algorithm type of the public key: if the public key is of type "DSA" then the algorithm "SHA1withDSA" is used, in case of an "RSA" key it is "MD5withRSA". Keys generated with the keytool for the standard Java 2 keystore are of type "DSA" if not specified otherwise. The creation of certificates has to be performed by a third party tool, such as the ones provided with OpenSSL.

The JCE signing engine that is used can not be specified for the moment, this class simply uses the first available one.

To repeat: It is up to the user of this class to assign trust to such an extension, this class can only be used to transfer an extension secured from unnoticed changes.

Remark: to simplify the security auditing of this class, the necessary and constant parameters are passed to the constructor and no additional setter-methods are available.

Version:

$Revision: 1.1.1.1 $

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Field Summary
private static java.security.KeyPair	keyPair
private  java.security.PublicKey	publicKey
private  java.security.SignedObject	signedExtension
(package private)  boolean	verified
(package private)  Aspect	wrappedExtension

 

Fields inherited from class ch.ethz.prose.Aspect

aspectID, birthDayCount, priority

 

Constructor Summary

SignedAspect(Aspect extension, java.security.KeyPair keys)           Constructs a signed extension and protects it from being modified unnoticed.

 

Method Summary
protected  ch.ethz.prose.crosscut.Crosscut[]	crosscuts()           This is a template meethod.
boolean	equals(java.lang.Object o)           Delegate to wrapped extension
java.util.List	getCrosscuts()           Return a list of crosscuts owned by this Aspect.
Aspect	getExtension()           Returns wrapped extension without checking it for being signed by a key corresponding to the public key stored.
java.security.PublicKey	getPublicKey()           Returns public key that possibly corresponds to signing key
java.lang.String	getSigningAlgorithm()           Returns signing algorithm name
int	hashCode()           delegate to wrapped extension
void	insertionAction(boolean beforeInsertion)           This method is called before and after this aspect is inserted into an AspectManager.
static SignedAspect	signExtension(Aspect ext)           Convinience method to sign extensions.
java.lang.String	toString()           Implementation: we don't use getExtension() here, as we don't want to de-marshall extension just because of the toString call
void	verifyExtension()           Verifies that the public key stored in this object corresponds to the private key used to sign the extension.
void	withdrawalAction(boolean beforeWithdrawal)           this method is called before and after the withdrawal of an aspect.

 

Methods inherited from class ch.ethz.prose.Aspect

associateTo, generateUniqueAssociation, getAssociatedObject, getPriority, setPriority

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

 

Field Detail

keyPair

private static java.security.KeyPair keyPair

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signedExtension

private java.security.SignedObject signedExtension

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publicKey

private java.security.PublicKey publicKey

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wrappedExtension

transient Aspect wrappedExtension

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verified

transient boolean verified

Constructor Detail

SignedAspect

public SignedAspect(Aspect extension,
                    java.security.KeyPair keys)

Constructs a signed extension and protects it from being modified unnoticed. Only the public key from the key pair passed is store in the generated object.

Method Detail

insertionAction

public void insertionAction(boolean beforeInsertion)
                     throws AspectInsertionException

Description copied from class: Aspect

This method is called before and after this aspect is inserted into an AspectManager. By overriding the default (which is a no-op), one can define setup actions. If this method throws an exception, the aspect insertion fails.

Specified by:

insertionAction in interface Insertable

Overrides:

insertionAction in class Aspect

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withdrawalAction

public void withdrawalAction(boolean beforeWithdrawal)

Description copied from class: Aspect

this method is called before and after the withdrawal of an aspect.

Specified by:

withdrawalAction in interface Insertable

Overrides:

withdrawalAction in class Aspect

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crosscuts

protected ch.ethz.prose.crosscut.Crosscut[] crosscuts()

Description copied from class: Aspect

This is a template meethod. Users must define this method to return a list of crosscut objects that belong to this aspect

Specified by:

crosscuts in class Aspect

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getCrosscuts

public java.util.List getCrosscuts()

Description copied from class: Aspect

Return a list of crosscuts owned by this Aspect. Note that this method returns the same list of objects during the existence of asspect. This list is initialized using the crosscuts template method.

Overrides:

getCrosscuts in class Aspect

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signExtension

public static SignedAspect signExtension(Aspect ext)

Convinience method to sign extensions. Throws IllegalStateException if signing is not possible.

FIX: CONTAINS A LOT OF HARD CODED STUFF!!!!

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verifyExtension

public void verifyExtension()
                     throws java.security.NoSuchAlgorithmException,
                            java.security.SignatureException,
                            java.security.InvalidKeyException

Verifies that the public key stored in this object corresponds to the private key used to sign the extension.

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getExtension

public Aspect getExtension()

Returns wrapped extension without checking it for being signed by a key corresponding to the public key stored.

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getPublicKey

public java.security.PublicKey getPublicKey()

Returns public key that possibly corresponds to signing key

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getSigningAlgorithm

public java.lang.String getSigningAlgorithm()

Returns signing algorithm name

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toString

public java.lang.String toString()

Implementation: we don't use getExtension() here, as we don't want to de-marshall extension just because of the toString call

Overrides:

toString in class Aspect

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equals

public boolean equals(java.lang.Object o)

Delegate to wrapped extension

Overrides:

equals in class Aspect

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hashCode

public int hashCode()

delegate to wrapped extension

Overrides:

hashCode in class Aspect

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> ch >> ethz >> [ prose overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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