SICSeekableBlockCipher (TrueZIP Driver TZP (ZIP.RAES) 7.0-rc1 API)

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TrueZIP Driver TZP (ZIP.RAES) 7.0-rc1

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de.schlichtherle.truezip.crypto
Class SICSeekableBlockCipher

java.lang.Object
  de.schlichtherle.truezip.crypto.SICSeekableBlockCipher

All Implemented Interfaces:: SeekableBlockCipher, BlockCipher

public class SICSeekableBlockCipher
extends Object
implements SeekableBlockCipher
extends Object
implements SeekableBlockCipher

Implements Counter (CTR) mode (alias Segmented Integer Counter - SIC). on top of a simple block cipher. This code is based on bouncy castle's SICBlockCipher class, but also allows random access to a block.

Author:: The Legion of the Bouncy Castle (majority of the code), Christian Schlichtherle (optimizations and extension to support seeking)

Field Summary
`private long`	`blockCounter`
`private int`	`blockSize`
`private BlockCipher`	`cipher`
`private byte[]`	`counterIn`
`private byte[]`	`counterOut`
`private byte[]`	`IV`

Constructor Summary
`SICSeekableBlockCipher(BlockCipher cipher)` Basic constructor.

Method Summary
`String`	`getAlgorithmName()`
`long`	`getBlockCounter()` Returns the index of the block, starting at 0, which will be processed next when `BlockCipher.processBlock(byte[], int, byte[], int)` is called.
`int`	`getBlockSize()`
`BlockCipher`	`getUnderlyingCipher()` Returns the underlying block cipher which we are decorating.
`void`	`init(boolean forEncryption, CipherParameters params)`
`int`	`processBlock(byte[] in, int inOff, byte[] out, int outOff)`
`void`	`reset()`
`void`	`setBlockCounter(long block)` Sets the counter so that the block with the given index, starting at 0, can be processed next.
`private void`	`updateCounter()`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

cipher

private final BlockCipher cipher

blockSize

private final int blockSize

IV

private final byte[] IV

counterIn

private final byte[] counterIn

blockCounter

private long blockCounter

counterOut

private final byte[] counterOut

Constructor Detail

SICSeekableBlockCipher

public SICSeekableBlockCipher(BlockCipher cipher)

Basic constructor.

Parameters:: cipher - The block cipher to be used.

Method Detail

getUnderlyingCipher

public BlockCipher getUnderlyingCipher()

Returns the underlying block cipher which we are decorating.

Returns:: The underlying block cipher which we are decorating.

init

public void init(boolean forEncryption,
                 CipherParameters params)
          throws IllegalArgumentException

Specified by:: init in interface BlockCipher

Throws:: IllegalArgumentException

getAlgorithmName

public String getAlgorithmName()

Specified by:: getAlgorithmName in interface BlockCipher

getBlockSize

public int getBlockSize()

Specified by:: getBlockSize in interface BlockCipher

processBlock

public int processBlock(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        IllegalStateException

Specified by:: processBlock in interface BlockCipher

Throws:: DataLengthException; IllegalStateException

updateCounter

private void updateCounter()

setBlockCounter

public void setBlockCounter(long block)

Description copied from interface: SeekableBlockCipher

Sets the counter so that the block with the given index, starting at 0, can be processed next.

Specified by:: setBlockCounter in interface SeekableBlockCipher

Parameters:: block - The index of the block, starting at 0, which will be processed next when BlockCipher.processBlock(byte[], int, byte[], int) is called.

getBlockCounter

public long getBlockCounter()