Overview  Package   Class  Use  Deprecated  Index
Home >> All >> cryptix >> jce >> provider >> [ cipher overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---

cryptix.jce.provider.cipher
Class ModeCFB  

java.lang.Object
  cryptix.jce.provider.cipher.Mode
      cryptix.jce.provider.cipher.ModeCFB

Direct Known Subclasses:

ModeOpenpgpCFB

---

class ModeCFB

extends Mode

Version:

$Revision: 1.5 $

---

Field Summary
protected  int	bufCount           How many bytes the buffer holds
protected  long	byteCount           How many bytes we have processed.
protected  BlockCipher	cipher           Underlying block cipher
protected  int	CIPHER_BLOCK_SIZE           Block size of underlying cipher
private  boolean	decrypt           Decrypt mode?
private  int	feedbackSize           Feedback size in bytes.
private  byte[]	iVec           IV.
private  byte[]	keyStreamBuf           Key stream aka encrypted shift register.
private  int	keyStreamPtr           Ptr to next usable byte in key stream buffer.
private  byte[]	shiftReg           Shift register.
private  int	shiftRegPtr           Where the next shifted-in byte will be put.

 

Constructor Summary
(package private)	ModeCFB(BlockCipher cipher)           Construct CFB mode with a feedback size equal to the block size of the underlying cipher.
(package private)	ModeCFB(BlockCipher cipher, int feedbackSize)           Construct CFB mode with the given feedback size.

 

Method Summary
(package private)  byte[]	coreGetIV()
(package private)  int	coreGetOutputSize(int inputLen)
(package private)  java.security.spec.AlgorithmParameterSpec	coreGetParamSpec()
(package private)  void	coreInit(boolean decrypt, java.security.Key key, java.security.spec.AlgorithmParameterSpec params, java.security.SecureRandom random)
(package private)  int	coreUpdate(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)
private  void	crank()           Sync aka encrypt the shift register to yield the next block of key stream bytes.
protected  byte[]	extractIV(java.security.spec.AlgorithmParameterSpec params)
protected  byte[]	generateIV()
(package private)  int	getBlockSize()
(package private)  int	getBufSize()
(package private) static Mode	getInstance(java.lang.String mode, BlockCipher cipher)
(package private)  byte[]	getIV()
(package private)  int	getOutputSize(int inputLen)
(package private)  java.security.spec.AlgorithmParameterSpec	getParamSpec()
(package private)  void	init(boolean decrypt, java.security.Key key, java.security.spec.AlgorithmParameterSpec params, java.security.SecureRandom random)
protected  boolean	needCrank()           Sync policy, can be overridden in subclasses.
(package private)  boolean	needsPadding()
private  void	shiftInByte(byte b)           Shift a byte into the shift register and 'sync' (encrypt shift reg) if neccessary.
(package private)  int	update(byte[] input, int inputOffset, int inputLen, byte[] output, int outputOffset)

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

keyStreamBuf

private final byte[] keyStreamBuf

Key stream aka encrypted shift register.

---

keyStreamPtr

private int keyStreamPtr

Ptr to next usable byte in key stream buffer.

---

shiftReg

private final byte[] shiftReg

Shift register. Implemented as a circular buffer.

---

shiftRegPtr

private int shiftRegPtr

Where the next shifted-in byte will be put.

---

byteCount

protected long byteCount

How many bytes we have processed. Used to determine when to 'sync'.

---

feedbackSize

private int feedbackSize

Feedback size in bytes. Valid settings are between 1 and the underlying cipher's blocksize inclusive.

---

decrypt

private boolean decrypt

Decrypt mode?

---

iVec

private byte[] iVec

IV.

---

cipher

protected final BlockCipher cipher

Underlying block cipher

---

CIPHER_BLOCK_SIZE

protected final int CIPHER_BLOCK_SIZE

Block size of underlying cipher

---

bufCount

protected int bufCount

How many bytes the buffer holds

Constructor Detail

ModeCFB

ModeCFB(BlockCipher cipher)

Construct CFB mode with a feedback size equal to the block size of the underlying cipher.

---

ModeCFB

ModeCFB(BlockCipher cipher,
        int feedbackSize)
  throws java.security.NoSuchAlgorithmException

Construct CFB mode with the given feedback size. Feedback size must be expressed in bits, be a multiple of 8, greater than 0 and smaller than the underlying cipher's block size.

Method Detail

shiftInByte

private void shiftInByte(byte b)

Shift a byte into the shift register and 'sync' (encrypt shift reg) if neccessary.

---

crank

private void crank()

Sync aka encrypt the shift register to yield the next block of key stream bytes.

---

needCrank

protected boolean needCrank()

Sync policy, can be overridden in subclasses.

---

coreGetOutputSize

final int coreGetOutputSize(int inputLen)

Specified by:

coreGetOutputSize in class Mode

---

coreInit

void coreInit(boolean decrypt,
              java.security.Key key,
              java.security.spec.AlgorithmParameterSpec params,
              java.security.SecureRandom random)
        throws java.security.InvalidKeyException,
               java.security.InvalidAlgorithmParameterException

Specified by:

coreInit in class Mode

---

coreUpdate

int coreUpdate(byte[] input,
               int inputOffset,
               int inputLen,
               byte[] output,
               int outputOffset)

Specified by:

coreUpdate in class Mode

---

coreGetIV

final byte[] coreGetIV()

Specified by:

coreGetIV in class Mode

---

coreGetParamSpec

final java.security.spec.AlgorithmParameterSpec coreGetParamSpec()

Specified by:

coreGetParamSpec in class Mode

---

needsPadding

final boolean needsPadding()

Specified by:

needsPadding in class Mode

---

getInstance

static Mode getInstance(java.lang.String mode,
                        BlockCipher cipher)
                 throws java.security.NoSuchAlgorithmException

---

init

void init(boolean decrypt,
          java.security.Key key,
          java.security.spec.AlgorithmParameterSpec params,
          java.security.SecureRandom random)
    throws java.security.InvalidKeyException,
           java.security.InvalidAlgorithmParameterException

---

getIV

final byte[] getIV()

---

getParamSpec

final java.security.spec.AlgorithmParameterSpec getParamSpec()

---

getOutputSize

final int getOutputSize(int inputLen)

---

getBlockSize

final int getBlockSize()

---

update

final int update(byte[] input,
                 int inputOffset,
                 int inputLen,
                 byte[] output,
                 int outputOffset)

---

getBufSize

final int getBufSize()

---

generateIV

protected byte[] generateIV()

---

extractIV

protected final byte[] extractIV(java.security.spec.AlgorithmParameterSpec params)
                          throws java.security.InvalidAlgorithmParameterException

---

Overview  Package   Class  Use  Deprecated  Index
Home >> All >> cryptix >> jce >> provider >> [ cipher overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---