org.opensaml.xml.encryption
Class Decrypter

java.lang.Object
  org.opensaml.xml.encryption.Decrypter

public class Decrypter
extends Object

Supports decryption of XMLObjects which represent data encrypted according to the XML Encryption specification, version 20021210.

Details on the components specified as constructor options are as follows:

1. newResolver: This KeyInfoCredentialResolver instance is used to resolve keys (as Credentials) based on the KeyInfo of EncryptedData elements. While it could in theory be used to handle the complete process of resolving the data decryption key, including decrypting any necessary EncryptedKey's, it would typically be used in cases where encrypted key transport via an EncryptedKey is not being employed. This corresponds to scenarios where decryption is instead based on resolving the (presumably shared secret) symmetric data decryption key directly, based on either context or information present in the EncryptedData's KeyInfo. In cases where the data decryption key is to be resolved by decrypting an EncryptedKey, this resolver would typically not be used and may be null.
2. newKEKResolver: This KeyInfoCredentialResolver instance is used to resolve keys (as Credentials) used to decrypt EncryptedKey elements, based on the KeyInfo information contained within the EncryptedKey element (also known as a Key Encryption Key or KEK). For asymmetric key transport of encrypted keys, this would entail resolving the private key which corresponds to the public key which was used to encrypt the EncryptedKey.
3. newEncKeyResolver: This EncryptedKeyResolver instance is responsible for resolving the EncryptedKey element(s) which hold(s) the encrypted data decryption key which would be used to decrypt an EncryptedData element.

XML Encryption can encrypt either a single Element or the contents of an Element. The caller of this class must select the decryption method which is most appropriate for their specific use case.

Note that the type of plaintext data contained by an EncryptedData can be checked prior to decryption by examining that element's type attribute (EncryptedType.getType()). This (optional) attribute may contain one of the following two constant values to aid in the decryption process: EncryptionConstants.TYPE_ELEMENT or EncryptionConstants.TYPE_CONTENT.

By nature the fundamental output of XML decryption is a DOM DocumentFragment with 1 or more immediate top-level DOM Node children. This case is reflected in the method decryptDataToDOM(EncryptedData). It is up to the caller to properly process the DOM Nodes which are the children of this document fragment. The DocumentFragment and its Node children will be owned by the DOM Document which owned the original EncryptedData before decryption. Note, however, that the Node children will not be a part of the tree of Nodes rooted at that Document's document element.

A typical use case will be that the content which was encrypted contained solely Element nodes. For this use case a convenience method is provided as decryptDataToList(EncryptedData), which returns a list of XMLObject's which are the result of unmarshalling each of the child Elements of the decrypted DocumentFragment.

Another typical use case is that the content which was encrypted was a single Element. For this use case a convenience method is provided as decryptData(EncryptedData), which returns a single XMLObject which was the result of unmarshalling this decrypted Element.

In both of these cases the underlying DOM Element which is represented by each of the returned XMLObjects will be owned by the DOM Document which also owns the original EncrytpedData Element. However, note that these cached DOM Elements are not part of the tree of Nodes rooted at that Document's document element. If these returned XMLObjects are then inserted as the children of other XMLObjects, it is up to the caller to ensure that the XMLObject tree is then remarshalled if the relationship of the cached DOM nodes is important (e.g. resolution of ID-typed attributes via Document.getElementById(String)).

For some use cases where the returned XMLObjects will not necessarily be stored back as children of another parent XMLObject, it may still necessary for the DOM Elements of the resultant XMLObjects to exist within the tree of Nodes rooted at a DOM Document's document element (e.g. signature verification on the standalone decrypted XMLObject). For these cases these method variants may be used: decryptDataToList(EncryptedData, boolean) and decryptData(EncryptedData, boolean). The rootInNewDocument parameter is explained below. A default value for this parameter, for the overloaded convenience methods which do not take this parameter explicitly, may be set via setRootInNewDocument(boolean). This default value is initialized to false.

If the boolean option rootInNewDocument is true at the time of decryption, then for each top-level child Element of the decrypted DocumentFragment, the following will occur:

1. A new DOM Document will be created.
2. The Element will be adopted into that Document.
3. The Element will be made the root element of the Document.
4. The Element will be unmarshalled into an XMLObject as in the single argument variant.

Note that new Document creation, node adoption and rooting the new document element are potentially very expensive. This should only be done where the caller's use case really requires it.

Field Summary

private boolean	defaultRootInNewDocument Flag to determine whether by default the Element which backs the underlying decrypted SAMLObject will be the root of a new DOM document.
private EncryptedKeyResolver	encKeyResolver Resolver for EncryptedKey instances which contain the encrypted data encryption key.
private String	jcaProviderName The name of the JCA security provider to use.
private KeyInfoCredentialResolver	kekResolver Resolver for key encryption keys.
private CriteriaSet	kekResolverCriteria Additional criteria to use when resolving credentials based on an EncryptedKey's KeyInfo.
private Logger	log Class logger.
private BasicParserPool	parserPool ParserPool used in parsing decrypted data.
private KeyInfoCredentialResolver	resolver Resolver for data encryption keys.
private CriteriaSet	resolverCriteria Additional criteria to use when resolving credentials based on an EncryptedData's KeyInfo.
private UnmarshallerFactory	unmarshallerFactory Unmarshaller factory, used in decryption of EncryptedData objects.

Constructor Summary

Decrypter(KeyInfoCredentialResolver newResolver, KeyInfoCredentialResolver newKEKResolver, EncryptedKeyResolver newEncKeyResolver)
Constructor.

Method Summary

private CriteriaSet	buildCredentialCriteria(EncryptedType encryptedType, CriteriaSet staticCriteria) Utility method to build a new set of credential criteria based on the KeyInfo of an EncryptedData or EncryptedKey, and any additional static criteria which might have been supplied to the decrypter.
private KeyAlgorithmCriteria	buildKeyAlgorithmCriteria(String encAlgorithmURI) Dynamically construct key algorithm credential criteria based on the specified algorithm URI.
private Set<Criteria>	buildKeyCriteria(EncryptedType encryptedType) Build decryption key credential criteria according to information in the encrypted type object.
private KeyLengthCriteria	buildKeyLengthCriteria(String encAlgorithmURI) Dynamically construct key length credential criteria based on the specified algorithm URI.
protected void	checkAndMarshall(XMLObject xmlObject) Ensure that the XMLObject is marshalled.
XMLObject	decryptData(EncryptedData encryptedData) This is a convenience method for calling decryptData(EncryptedData, boolean), with the rootInNewDocument parameter value supplied by isRootInNewDocument().
XMLObject	decryptData(EncryptedData encryptedData, boolean rootInNewDocument) Decrypts the supplied EncryptedData and returns the resulting XMLObject.
DocumentFragment	decryptDataToDOM(EncryptedData encryptedData) Decrypts the supplied EncryptedData and returns the resulting DOM DocumentFragment.
DocumentFragment	decryptDataToDOM(EncryptedData encryptedData, Key dataEncKey) Decrypts the supplied EncryptedData using the specified key, and returns the resulting DOM DocumentFragment.
List<XMLObject>	decryptDataToList(EncryptedData encryptedData) This is a convenience method for calling decryptDataToList(EncryptedData, boolean), with the rootInNewDocument parameter value supplied by isRootInNewDocument().
List<XMLObject>	decryptDataToList(EncryptedData encryptedData, boolean rootInNewDocument) Decrypts the supplied EncryptedData and returns the resulting list of XMLObjects.
Key	decryptKey(EncryptedKey encryptedKey, String algorithm) Attempts to decrypt the supplied EncryptedKey and returns the resulting Java security Key object.
Key	decryptKey(EncryptedKey encryptedKey, String algorithm, Key kek) Decrypts the supplied EncryptedKey and returns the resulting Java security Key object.
private DocumentFragment	decryptUsingResolvedEncryptedKey(EncryptedData encryptedData, String algorithm) Attempt to decrypt by resolving the decryption key by first resolving EncryptedKeys, and using the KEK credential resolver to resolve the key decryption for each.
private DocumentFragment	decryptUsingResolvedKey(EncryptedData encryptedData) Attempt to decrypt by resolving the decryption key using the standard credential resolver.
EncryptedKeyResolver	getEncryptedKeyResolver() Get the encrypted key resolver.
String	getJCAProviderName() Get the Java Cryptography Architecture (JCA) security provider name that should be used to provide the decryption support.
KeyInfoCredentialResolver	getKEKResolver() Get the key encryption key credential resolver.
CriteriaSet	getKEKResolverCriteria() Get the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedKey element.
KeyInfoCredentialResolver	getKeyResolver() Get the data encryption key credential resolver.
boolean	isRootInNewDocument() Get the flag which indicates whether by default the DOM Element which backs a decrypted SAML object will be the root of a new DOM document.
private DocumentFragment	parseInputStream(InputStream input, Document owningDocument) Parse the specified input stream in a DOM DocumentFragment, owned by the specified Document.
protected void	preProcessEncryptedKey(EncryptedKey encryptedKey, String algorithm, Key kek) Preprocess the EncryptedKey.
void	setEncryptedKeyResolver(EncryptedKeyResolver newResolver) Set a new encrypted key resolver.
void	setJCAProviderName(String providerName) Set the Java Cryptography Architecture (JCA) security provider name that should be used to provide the decryption support.
void	setKEKResolver(KeyInfoCredentialResolver newKEKResolver) Set a new key encryption key credential resolver.
void	setKEKResolverCriteria(CriteriaSet newCriteria) Set the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedKey element.
void	setKeyResolver(KeyInfoCredentialResolver newResolver) Set a new data encryption key credential resolver.
CriteriaSet	setKeyResolverCriteria() Get the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedData element.
void	setKeyResolverCriteria(CriteriaSet newCriteria) Set the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedData element.
void	setRootInNewDocument(boolean flag) Set the flag which indicates whether by default the DOM Element which backs a decrypted SAML object will be the root of a new DOM document.

Methods inherited from class java.lang.Object

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

Field Detail

parserPool

private final BasicParserPool parserPool

ParserPool used in parsing decrypted data.

unmarshallerFactory

private UnmarshallerFactory unmarshallerFactory

Unmarshaller factory, used in decryption of EncryptedData objects.

log

private final Logger log

Class logger.

resolver

private KeyInfoCredentialResolver resolver

Resolver for data encryption keys.

kekResolver

private KeyInfoCredentialResolver kekResolver

Resolver for key encryption keys.

encKeyResolver

private EncryptedKeyResolver encKeyResolver

Resolver for EncryptedKey instances which contain the encrypted data encryption key.

resolverCriteria

private CriteriaSet resolverCriteria

Additional criteria to use when resolving credentials based on an EncryptedData's KeyInfo.

kekResolverCriteria

private CriteriaSet kekResolverCriteria

Additional criteria to use when resolving credentials based on an EncryptedKey's KeyInfo.

jcaProviderName

private String jcaProviderName

The name of the JCA security provider to use.

defaultRootInNewDocument

private boolean defaultRootInNewDocument

Flag to determine whether by default the Element which backs the underlying decrypted SAMLObject will be the root of a new DOM document.

Constructor Detail

Decrypter

public Decrypter(KeyInfoCredentialResolver newResolver,
                 KeyInfoCredentialResolver newKEKResolver,
                 EncryptedKeyResolver newEncKeyResolver)

Constructor.

Parameters:

newResolver - resolver for data encryption keys.

newKEKResolver - resolver for key encryption keys.

newEncKeyResolver - resolver for EncryptedKey elements

Method Detail

isRootInNewDocument

public boolean isRootInNewDocument()

Get the flag which indicates whether by default the DOM Element which backs a decrypted SAML object will be the root of a new DOM document. Defaults to false.

Returns:

the current value of the flag for this decrypter instance

setRootInNewDocument

public void setRootInNewDocument(boolean flag)

Set the flag which indicates whether by default the DOM Element which backs a decrypted SAML object will be the root of a new DOM document. Defaults to false.

Parameters:

flag - the current value of the flag for this decrypter instance

getJCAProviderName

public String getJCAProviderName()

Get the Java Cryptography Architecture (JCA) security provider name that should be used to provide the decryption support. Defaults to null, which means that the first registered provider which supports the indicated encryption algorithm URI will be used.

Returns:

the JCA provider name to use

setJCAProviderName

public void setJCAProviderName(String providerName)

Set the Java Cryptography Architecture (JCA) security provider name that should be used to provide the decryption support. Defaults to null, which means that the first registered provider which supports the indicated encryption algorithm URI will be used.

Parameters:

providerName - the JCA provider name to use

getKeyResolver

public KeyInfoCredentialResolver getKeyResolver()

Get the data encryption key credential resolver.

Returns:

the data encryption key resolver

setKeyResolver

public void setKeyResolver(KeyInfoCredentialResolver newResolver)

Set a new data encryption key credential resolver.

Parameters:

newResolver - the new data encryption key resolver

getKEKResolver

public KeyInfoCredentialResolver getKEKResolver()

Get the key encryption key credential resolver.

Returns:

the key encryption key resolver

setKEKResolver

public void setKEKResolver(KeyInfoCredentialResolver newKEKResolver)

Set a new key encryption key credential resolver.

Parameters:

newKEKResolver - the new key encryption key resolver

getEncryptedKeyResolver

public EncryptedKeyResolver getEncryptedKeyResolver()

Get the encrypted key resolver.

Returns:

the encrypted key resolver

setEncryptedKeyResolver

public void setEncryptedKeyResolver(EncryptedKeyResolver newResolver)

Set a new encrypted key resolver.

Parameters:

newResolver - the new encrypted key resolver

setKeyResolverCriteria

public CriteriaSet setKeyResolverCriteria()

Get the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedData element.

Returns:

the static criteria set to use

setKeyResolverCriteria

public void setKeyResolverCriteria(CriteriaSet newCriteria)

Set the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedData element.

Parameters:

newCriteria - the static criteria set to use

getKEKResolverCriteria

public CriteriaSet getKEKResolverCriteria()

Get the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedKey element.

Returns:

the static criteria set to use

setKEKResolverCriteria

public void setKEKResolverCriteria(CriteriaSet newCriteria)

Set the optional static set of criteria used when resolving credentials based on the KeyInfo of an EncryptedKey element.

Parameters:

newCriteria - the static criteria set to use

decryptData

public XMLObject decryptData(EncryptedData encryptedData)
                      throws DecryptionException

This is a convenience method for calling decryptData(EncryptedData, boolean), with the rootInNewDocument parameter value supplied by isRootInNewDocument().

Parameters:

encryptedData - encrypted data element containing the data to be decrypted

Returns:

the decrypted XMLObject

Throws:

DecryptionException - exception indicating a decryption error, possibly because the decrypted data contained more than one top-level Element, or some non-Element Node type.

decryptData

public XMLObject decryptData(EncryptedData encryptedData,
                             boolean rootInNewDocument)
                      throws DecryptionException

Decrypts the supplied EncryptedData and returns the resulting XMLObject. This will only succeed if the decrypted EncryptedData contains exactly one DOM Node of type Element.

Parameters:

encryptedData - encrypted data element containing the data to be decrypted

rootInNewDocument - if true, root the underlying Element of the returned XMLObject in a new Document as described in Decrypter

Returns:

the decrypted XMLObject

Throws:

DecryptionException - exception indicating a decryption error, possibly because the decrypted data contained more than one top-level Element, or some non-Element Node type.

decryptDataToList

public List<XMLObject> decryptDataToList(EncryptedData encryptedData)
                                  throws DecryptionException

This is a convenience method for calling decryptDataToList(EncryptedData, boolean), with the rootInNewDocument parameter value supplied by isRootInNewDocument().

Parameters:

encryptedData - encrypted data element containing the data to be decrypted

Returns:

the list decrypted top-level XMLObjects

Throws:

DecryptionException - exception indicating a decryption error, possibly because the decrypted data contained DOM nodes other than type of Element

decryptDataToList

public List<XMLObject> decryptDataToList(EncryptedData encryptedData,
                                         boolean rootInNewDocument)
                                  throws DecryptionException

Decrypts the supplied EncryptedData and returns the resulting list of XMLObjects. This will succeed only if the decrypted EncryptedData contains at the top-level only DOM Elements (not other types of DOM Nodes).

Parameters:

encryptedData - encrypted data element containing the data to be decrypted

rootInNewDocument - if true, root the underlying Elements of the returned XMLObjects in a new Document as described in Decrypter

Returns:

the list decrypted top-level XMLObjects

Throws:

DecryptionException - exception indicating a decryption error, possibly because the decrypted data contained DOM nodes other than type of Element

decryptDataToDOM

public DocumentFragment decryptDataToDOM(EncryptedData encryptedData)
                                  throws DecryptionException

Decrypts the supplied EncryptedData and returns the resulting DOM DocumentFragment.

Parameters:

encryptedData - encrypted data element containing the data to be decrypted

Returns:

the decrypted DOM DocumentFragment

Throws:

DecryptionException - exception indicating a decryption error

decryptDataToDOM

public DocumentFragment decryptDataToDOM(EncryptedData encryptedData,
                                         Key dataEncKey)
                                  throws DecryptionException

Decrypts the supplied EncryptedData using the specified key, and returns the resulting DOM DocumentFragment.

Parameters:

encryptedData - encrypted data element containing the data to be decrypted

dataEncKey - Java Key with which to attempt decryption of the encrypted data

Returns:

the decrypted DOM DocumentFragment

Throws:

DecryptionException - exception indicating a decryption error

decryptKey

public Key decryptKey(EncryptedKey encryptedKey,
                      String algorithm)
               throws DecryptionException

Attempts to decrypt the supplied EncryptedKey and returns the resulting Java security Key object. The algorithm of the decrypted key must be supplied by the caller based on knowledge of the associated EncryptedData information.

Parameters:

encryptedKey - encrypted key element containing the encrypted key to be decrypted

algorithm - the algorithm associated with the decrypted key

Returns:

the decrypted key

Throws:

DecryptionException - exception indicating a decryption error

decryptKey

public Key decryptKey(EncryptedKey encryptedKey,
                      String algorithm,
                      Key kek)
               throws DecryptionException

Decrypts the supplied EncryptedKey and returns the resulting Java security Key object. The algorithm of the decrypted key must be supplied by the caller based on knowledge of the associated EncryptedData information.

Parameters:

encryptedKey - encrypted key element containing the encrypted key to be decrypted

algorithm - the algorithm associated with the decrypted key

kek - the key encryption key with which to attempt decryption of the encrypted key

Returns:

the decrypted key

Throws:

DecryptionException - exception indicating a decryption error

preProcessEncryptedKey

protected void preProcessEncryptedKey(EncryptedKey encryptedKey,
                                      String algorithm,
                                      Key kek)
                               throws DecryptionException

Preprocess the EncryptedKey. For example, check for supported algorithms.

Parameters:

encryptedKey - encrypted key element containing the encrypted key to be decrypted

algorithm - the algorithm associated with the decrypted key

kek - the key encryption key with which to attempt decryption of the encrypted key

Throws:

DecryptionException - exception indicating a decryption error

decryptUsingResolvedKey

private DocumentFragment decryptUsingResolvedKey(EncryptedData encryptedData)

Attempt to decrypt by resolving the decryption key using the standard credential resolver.

Parameters:

encryptedData - the encrypted data to decrypt

Returns:

the decrypted document fragment, or null if decryption key could not be resolved or decryption failed

decryptUsingResolvedEncryptedKey

private DocumentFragment decryptUsingResolvedEncryptedKey(EncryptedData encryptedData,
                                                          String algorithm)

Attempt to decrypt by resolving the decryption key by first resolving EncryptedKeys, and using the KEK credential resolver to resolve the key decryption for each.

Parameters:

encryptedData - the encrypted data to decrypt

algorithm - the algorithm of the key to be decrypted

Returns:

the decrypted document fragment, or null if decryption key could not be resolved or decryption failed

parseInputStream

private DocumentFragment parseInputStream(InputStream input,
                                          Document owningDocument)
                                   throws DecryptionException

Parse the specified input stream in a DOM DocumentFragment, owned by the specified Document.

Parameters:

input - the InputStream to parse

owningDocument - the Document which will own the returned DocumentFragment

Returns:

a DocumentFragment

Throws:

DecryptionException - thrown if there is an error parsing the input stream

buildCredentialCriteria

private CriteriaSet buildCredentialCriteria(EncryptedType encryptedType,
                                            CriteriaSet staticCriteria)

Utility method to build a new set of credential criteria based on the KeyInfo of an EncryptedData or EncryptedKey, and any additional static criteria which might have been supplied to the decrypter.

Parameters:

encryptedType - an EncryptedData or EncryptedKey for which to resolve decryption credentials

staticCriteria - static set of credential criteria to add to the new criteria set

Returns:

the new credential criteria set

buildKeyCriteria

private Set<Criteria> buildKeyCriteria(EncryptedType encryptedType)

Build decryption key credential criteria according to information in the encrypted type object.

Parameters:

encryptedType - the encrypted type from which to deduce decryption key criteria

Returns:

a set of credential criteria pertaining to the decryption key

buildKeyAlgorithmCriteria

private KeyAlgorithmCriteria buildKeyAlgorithmCriteria(String encAlgorithmURI)

Dynamically construct key algorithm credential criteria based on the specified algorithm URI.

Parameters:

encAlgorithmURI - the algorithm URI

Returns:

a new key algorithm credential criteria instance, or null if criteria could not be determined

buildKeyLengthCriteria

private KeyLengthCriteria buildKeyLengthCriteria(String encAlgorithmURI)

Dynamically construct key length credential criteria based on the specified algorithm URI.

Parameters:

encAlgorithmURI - the algorithm URI

Returns:

a new key length credential criteria instance, or null if the value could not be determined

checkAndMarshall

protected void checkAndMarshall(XMLObject xmlObject)
                         throws DecryptionException

Ensure that the XMLObject is marshalled.

Parameters:

xmlObject - the object to check and marshall

Throws:

DecryptionException - thrown if there is an error when marshalling the XMLObject