Class Decrypter

java.lang.Object
org.opensaml.xmlsec.encryption.support.Decrypter
Direct Known Subclasses:
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 Details

    • parserPool

      private final ParserPool parserPool
      ParserPool used in parsing decrypted data.
    • unmarshallerFactory

      private final UnmarshallerFactory unmarshallerFactory
      Unmarshaller factory, used in decryption of EncryptedData objects.
    • log

      private final org.slf4j.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.
    • includedAlgorithmURIs

      private Collection<String> includedAlgorithmURIs
      The collection of algorithm URIs which are included.
    • excludedAlgorithmURIs

      private Collection<String> excludedAlgorithmURIs
      The collection of algorithm URIs which are excluded.
    • 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 Details

    • Decrypter

      public Decrypter​(DecryptionParameters params)
      Constructor.
      Parameters:
      params - decryption parameters to use
    • Decrypter

      public Decrypter​(@Nullable KeyInfoCredentialResolver newResolver, @Nullable KeyInfoCredentialResolver newKEKResolver, @Nullable EncryptedKeyResolver newEncKeyResolver)
      Constructor.
      Parameters:
      newResolver - resolver for data encryption keys.
      newKEKResolver - resolver for key encryption keys.
      newEncKeyResolver - resolver for EncryptedKey elements
    • Decrypter

      public Decrypter​(@Nullable KeyInfoCredentialResolver newResolver, @Nullable KeyInfoCredentialResolver newKEKResolver, @Nullable EncryptedKeyResolver newEncKeyResolver, @Nullable Collection<String> includeAlgos, @Nullable Collection<String> excludeAlgos)
      Constructor.
      Parameters:
      newResolver - resolver for data encryption keys.
      newKEKResolver - resolver for key encryption keys.
      newEncKeyResolver - resolver for EncryptedKey elements
      includeAlgos - collection of included algorithm URIs
      excludeAlgos - collection of excluded algorithm URIs
    • Decrypter

      private Decrypter()
      Constructor.
  • Method Details

    • 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

      @Nullable 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​(@Nullable 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
    • getKeyResolverCriteria

      public CriteriaSet getKeyResolverCriteria()
      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

      @Nonnull public XMLObject decryptData​(@Nonnull 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

      @Nonnull public XMLObject decryptData​(@Nonnull 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

      @Nonnull public List<XMLObject> decryptDataToList​(@Nonnull 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

      @Nonnull public List<XMLObject> decryptDataToList​(@Nonnull 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

      @Nonnull public DocumentFragment decryptDataToDOM​(@Nonnull 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

      @Nonnull public DocumentFragment decryptDataToDOM​(@Nonnull EncryptedData encryptedData, @Nonnull 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

      @Nonnull public Key decryptKey​(@Nonnull EncryptedKey encryptedKey, @Nonnull 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

      @Nonnull public Key decryptKey​(@Nonnull EncryptedKey encryptedKey, @Nonnull String algorithm, @Nonnull 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​(@Nonnull EncryptedKey encryptedKey, @Nonnull String algorithm, @Nonnull 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

      @Nullable private DocumentFragment decryptUsingResolvedKey​(@Nonnull 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

      @Nullable private DocumentFragment decryptUsingResolvedEncryptedKey​(@Nonnull EncryptedData encryptedData, @Nonnull 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

      @Nonnull private DocumentFragment parseInputStream​(@Nonnull InputStream input, @Nonnull 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

      @Nonnull private CriteriaSet buildCredentialCriteria​(@Nonnull EncryptedType encryptedType, @Nullable 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

      @Nullable private Set<Criterion> buildKeyCriteria​(@Nonnull 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

      @Nullable private KeyAlgorithmCriterion buildKeyAlgorithmCriteria​(@Nullable 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

      @Nullable private KeyLengthCriterion buildKeyLengthCriteria​(@Nullable 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​(@Nonnull 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
    • buildParserPool

      @Deprecated protected ParserPool buildParserPool()
      Deprecated.
      Build the internal parser pool instance used to parse decrypted XML.

      Note: When using a Xerces parser or derivative, the following feature must be set to false: http://apache.org/xml/features/dom/defer-node-expansion

      Returns:
      a new parser pool instance
    • validateAlgorithms

      protected void validateAlgorithms​(@Nonnull EncryptedKey encryptedKey) throws DecryptionException
      Validate the algorithms contained within an EncryptedKey.
      Parameters:
      encryptedKey - the encrypted key instance to validate
      Throws:
      DecryptionException - if any algorithms do not satisfy include/exclude policy
    • validateAlgorithms

      protected void validateAlgorithms​(@Nonnull EncryptedData encryptedData) throws DecryptionException
      Validate the algorithms contained within an EncryptedData.
      Parameters:
      encryptedData - the encrypted data instance to validate
      Throws:
      DecryptionException - if any algorithms do not satisfy include/exclude policy
    • validateAlgorithmURI

      protected void validateAlgorithmURI​(@Nonnull String algorithmURI) throws DecryptionException
      Validate the supplied algorithm URI against the configured include and exclude lists.
      Parameters:
      algorithmURI - the algorithm URI to evaluate
      Throws:
      DecryptionException - if the algorithm URI does not satisfy the include/exclude policy