gnu.crypto.assembly
public abstract class Stage extends Object
A Stage in a Cascade Cipher.
Each stage may be either an implementation of a Block Cipher Mode of Operation (IMode) or another Cascade Cipher (Cascade). Each stage has also a natural operational direction when constructed for inclusion within a Cascade. This natural direction dictates how data flows from one stage into another when stages are chained together in a cascade. One can think of a stage and its natural direction as the specification of how to wire the stage into the chain. The following diagrams may help understand the paradigme. The first shows two stages chained each with a FORWARD direction.
FORWARD FORWARD +------+ +-------+ | | | | | +--in --+ | +--in --+ ---+ | Stage | | | Stage | +--- +--out--+ | +--out--+ | | | | | +-------+ +------+
The second diagram shows two stages, one in a FORWARD direction, while the other is wired in a REVERSED direction.
FORWARD REVERSED +------+ +------+ | | | | | +--in --+ +--in --+ | ---+ | Stage | | Stage | +--- +--out--+ +--out--+ | | +---------------+
Version: $Revision: 1.7 $
See Also: ModeStage CascadeStage
Field Summary | |
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static String | DIRECTION |
protected Direction | forward |
protected Direction | wired |
Constructor Summary | |
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protected | Stage(Direction forwardDirection) |
Method Summary | |
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abstract Set | blockSizes()
Returns the Set of supported block sizes for this
Stage . |
abstract int | currentBlockSize()
Returns the currently set block size for the stage.
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static Stage | getInstance(IMode mode, Direction forwardDirection) |
static Stage | getInstance(Cascade cascade, Direction forwardDirection) |
void | init(Map attributes)
Initialises the stage for operation with specific characteristics.
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abstract void | initDelegate(Map attributes) |
void | reset()
Resets the stage for re-initialisation and use with other characteristics.
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abstract void | resetDelegate() |
abstract boolean | selfTest()
Conducts a simple correctness test that consists of basic symmetric
encryption / decryption test(s) for all supported block and key sizes of
underlying block cipher(s) wrapped by Mode leafs. |
void | update(byte[] in, int inOffset, byte[] out, int outOffset) |
abstract void | updateDelegate(byte[] in, int inOffset, byte[] out, int outOffset) |
Stage
. Each element in the returned Set is an
instance of Integer.
Returns: a Set of supported block sizes.
Returns: the current block size for this stage.
Throws: IllegalStateException if the instance is not initialised.
Parameters: attributes a set of name-value pairs that describes the desired future behaviour of this instance.
Throws: IllegalStateException if the instance is already initialised. InvalidKeyException if the key data is invalid.
Returns: true
if the implementation passes simple
correctness tests. Returns false
otherwise.
Parameters: in the plaintext. inOffset index of in
from which to start considering
data. out the ciphertext. outOffset index of out
from which to store result.
Throws: IllegalStateException if the instance is not initialised.