JavaTM 2 Platform
Std. Ed. v1.4.2

javax.crypto
Class SealedObject

java.lang.Object
  extended byjavax.crypto.SealedObject
All Implemented Interfaces:
Serializable

public class SealedObject
extends Object
implements Serializable

This class enables a programmer to create an object and protect its confidentiality with a cryptographic algorithm.

Given any Serializable object, one can create a SealedObject that encapsulates the original object, in serialized format (i.e., a "deep copy"), and seals (encrypts) its serialized contents, using a cryptographic algorithm such as DES, to protect its confidentiality. The encrypted content can later be decrypted (with the corresponding algorithm using the correct decryption key) and de-serialized, yielding the original object.

Note that the Cipher object must be fully initialized with the correct algorithm, key, padding scheme, etc., before being applied to a SealedObject.

The original object that was sealed can be recovered in two different ways:

Since:
1.4
See Also:
Cipher, Serialized Form

Field Summary
protected  byte[] encodedParams
          The encoded parameters.
 
Constructor Summary
protected SealedObject(SealedObject so)
          Constructs a SealedObject object from the passed-in SealedObject.
  SealedObject(Serializable object, Cipher c)
          Constructs a SealedObject from any Serializable object.
 
Method Summary
 String getAlgorithm()
          Returns the algorithm that was used to seal this object.
 Object getObject(Cipher c)
          Retrieves the original (encapsulated) object.
 Object getObject(Key key)
          Retrieves the original (encapsulated) object.
 Object getObject(Key key, String provider)
          Retrieves the original (encapsulated) object.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

encodedParams

protected byte[] encodedParams
The encoded parameters.

Constructor Detail

SealedObject

public SealedObject(Serializable object,
                    Cipher c)
             throws IOException,
                    IllegalBlockSizeException
Constructs a SealedObject from any Serializable object.

The given object is serialized, and its serialized contents are encrypted using the given Cipher, which must be fully initialized.

Any algorithm parameters that may be used in the encryption operation are stored inside of the new SealedObject.

Parameters:
object - the object to be sealed.
c - the cipher used to seal the object.
Throws:
IOException - if an error occurs during serialization
IllegalBlockSizeException - if the given cipher is a block cipher, no padding has been requested, and the total input length (i.e., the length of the serialized object contents) is not a multiple of the cipher's block size

SealedObject

protected SealedObject(SealedObject so)
Constructs a SealedObject object from the passed-in SealedObject.

Parameters:
so - a SealedObject object
Method Detail

getAlgorithm

public final String getAlgorithm()
Returns the algorithm that was used to seal this object.

Returns:
the algorithm that was used to seal this object.

getObject

public final Object getObject(Key key)
                       throws IOException,
                              ClassNotFoundException,
                              NoSuchAlgorithmException,
                              InvalidKeyException
Retrieves the original (encapsulated) object.

This method creates a cipher for the algorithm that had been used in the sealing operation. If the default provider package provides an implementation of that algorithm, an instance of Cipher containing that implementation is used. If the algorithm is not available in the default package, other packages are searched. The Cipher object is initialized for decryption, using the given key and the parameters (if any) that had been used in the sealing operation.

The encapsulated object is unsealed and de-serialized, before it is returned.

Parameters:
key - the key used to unseal the object.
Returns:
the original object.
Throws:
IOException - if an error occurs during de-serialiazation.
ClassNotFoundException - if an error occurs during de-serialiazation.
NoSuchAlgorithmException - if the algorithm to unseal the object is not available.
InvalidKeyException - if the given key cannot be used to unseal the object (e.g., it has the wrong algorithm).

getObject

public final Object getObject(Cipher c)
                       throws IOException,
                              ClassNotFoundException,
                              IllegalBlockSizeException,
                              BadPaddingException
Retrieves the original (encapsulated) object.

The encapsulated object is unsealed (using the given Cipher, assuming that the Cipher is already properly initialized) and de-serialized, before it is returned.

Parameters:
c - the cipher used to unseal the object
Returns:
the original object.
Throws:
IOException - if an error occurs during de-serialiazation
ClassNotFoundException - if an error occurs during de-serialiazation
IllegalBlockSizeException - if the given cipher is a block cipher, no padding has been requested, and the total input length is not a multiple of the cipher's block size
BadPaddingException - if the given cipher has been initialized for decryption, and padding has been specified, but the input data does not have proper expected padding bytes

getObject

public final Object getObject(Key key,
                              String provider)
                       throws IOException,
                              ClassNotFoundException,
                              NoSuchAlgorithmException,
                              NoSuchProviderException,
                              InvalidKeyException
Retrieves the original (encapsulated) object.

This method creates a cipher for the algorithm that had been used in the sealing operation, using an implementation of that algorithm from the given provider. The Cipher object is initialized for decryption, using the given key and the parameters (if any) that had been used in the sealing operation.

The encapsulated object is unsealed and de-serialized, before it is returned.

Parameters:
key - the key used to unseal the object.
provider - the name of the provider of the algorithm to unseal the object.
Returns:
the original object.
Throws:
IOException - if an error occurs during de-serialiazation.
ClassNotFoundException - if an error occurs during de-serialiazation.
NoSuchAlgorithmException - if the algorithm to unseal the object is not available.
NoSuchProviderException - if the given provider is not configured.
InvalidKeyException - if the given key cannot be used to unseal the object (e.g., it has the wrong algorithm).

JavaTM 2 Platform
Std. Ed. v1.4.2

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