Class SealedObject
- All Implemented Interfaces:
Serializable
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 AES, 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:
- by using the
getObjectmethod that takes aCipherobject.This method requires a fully initialized
Cipherobject, initialized with the exact same algorithm, key, padding scheme, etc., that were used to seal the object.This approach has the advantage that the party who unseals the sealed object does not require knowledge of the decryption key. For example, after one party has initialized the cipher object with the required decryption key, it could hand over the cipher object to another party who then unseals the sealed object.
- by using one of the
getObjectmethods that take aKeyobject.In this approach, the
getObjectmethod creates a cipher object for the appropriate decryption algorithm and initializes it with the given decryption key and the algorithm parameters (if any) that were stored in the sealed object.This approach has the advantage that the party who unseals the object does not need to keep track of the parameters (e.g., an IV) that were used to seal the object.
- Since:
- 1.4
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected byte[]The cryptographic parameters used by the sealingCipherobject, encoded in the default format. -
Constructor Summary
ConstructorsModifierConstructorDescriptionSealedObject(Serializable object, Cipher c) Constructs aSealedObjectfrom anySerializableobject.protectedConstructs aSealedObjectobject from the passed-inSealedObject. -
Method Summary
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Field Details
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encodedParams
protected byte[] encodedParamsThe cryptographic parameters used by the sealingCipherobject, encoded in the default format.That is,
Cipher.getParameters().getEncoded().
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Constructor Details
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SealedObject
Constructs aSealedObjectfrom anySerializableobject.The given object is serialized, and its serialized contents are encrypted using the given
Cipherobject, which must be fully initialized.Any algorithm parameters that may be used in the encryption operation are stored inside the new
SealedObject.- Parameters:
object- the object to be sealed; can benull.c- the cipher used to seal the object.- Throws:
NullPointerException- if the given cipher isnull.IOException- if an error occurs during serializationIllegalBlockSizeException- 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
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SealedObject
Constructs aSealedObjectobject from the passed-inSealedObject.- Parameters:
so- aSealedObjectobject- Throws:
NullPointerException- if the given sealed object isnull.
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Method Details
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getAlgorithm
Returns the algorithm that was used to seal this object.- Returns:
- the algorithm that was used to seal this object.
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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, a
Cipherobject containing that implementation is used. If the algorithm is not available in the default package, other packages are searched. TheCipherobject is initialized for decryption, using the givenkeyand 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-serialization.ClassNotFoundException- if an error occurs during de-serialization.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).NullPointerException- ifkeyis null.
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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
Cipherobject, assuming that theCipherobject 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:
NullPointerException- if the given cipher isnull.IOException- if an error occurs during de-serializationClassNotFoundException- if an error occurs during de-serializationIllegalBlockSizeException- 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 sizeBadPaddingException- 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
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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. TheCipherobject is initialized for decryption, using the givenkeyand 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:
IllegalArgumentException- if the given provider isnullor empty.IOException- if an error occurs during de-serialization.ClassNotFoundException- if an error occurs during de-serialization.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).NullPointerException- ifkeyis null.
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