gnu.crypto.jce.cipher
Class ARCFourSpi

java.lang.Object
  |
  +--javax.crypto.CipherSpi
        |
        +--gnu.crypto.jce.cipher.ARCFourSpi

public class ARCFourSpi

extends CipherSpi

The Service Provider Interface (SPI) for the ARCFOUR stream cipher.

Constructor Summary

ARCFourSpi()

Method Summary

protected byte[]	engineDoFinal(byte[] in, int offset, int length) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
protected int	engineDoFinal(byte[] in, int inOffset, int length, byte[] out, int outOffset) Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation.
protected int	engineGetBlockSize() Returns the block size (in bytes).
protected byte[]	engineGetIV() Returns the initialization vector (IV) in a new buffer.
protected int	engineGetOutputSize(int in) Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update or doFinal operation, given the input length inputLen (in bytes).
protected java.security.AlgorithmParameters	engineGetParameters() Returns the parameters used with this cipher.
protected void	engineInit(int mode, java.security.Key key, java.security.spec.AlgorithmParameterSpec p, java.security.SecureRandom r) Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.
protected void	engineInit(int mode, java.security.Key key, java.security.AlgorithmParameters p, java.security.SecureRandom r) Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.
protected void	engineInit(int mode, java.security.Key key, java.security.SecureRandom r) Initializes this cipher with a key and a source of randomness.
protected void	engineSetMode(java.lang.String s) Sets the mode of this cipher.
protected void	engineSetPadding(java.lang.String s) Sets the padding mechanism of this cipher.
protected byte[]	engineUpdate(byte[] in, int offset, int length) Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.
protected int	engineUpdate(byte[] in, int inOffset, int length, byte[] out, int outOffset) Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

Methods inherited from class javax.crypto.CipherSpi

engineGetKeySize, engineUnwrap, engineWrap

Methods inherited from class java.lang.Object

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

Constructor Detail

ARCFourSpi

public ARCFourSpi()

Method Detail

engineGetBlockSize

protected int engineGetBlockSize()

Description copied from class: CipherSpi

Returns the block size (in bytes).

Specified by:

engineGetBlockSize in class CipherSpi

Returns:

the block size (in bytes), or 0 if the underlying algorithm is not a block cipher

engineSetMode

protected void engineSetMode(java.lang.String s)
                      throws java.security.NoSuchAlgorithmException

Description copied from class: CipherSpi

Sets the mode of this cipher.

Specified by:

engineSetMode in class CipherSpi

Parameters:

s - the cipher mode

Throws:

java.security.NoSuchAlgorithmException - if the requested cipher mode does not exist

engineSetPadding

protected void engineSetPadding(java.lang.String s)
                         throws NoSuchPaddingException

Description copied from class: CipherSpi

Sets the padding mechanism of this cipher.

Specified by:

engineSetPadding in class CipherSpi

Parameters:

s - the padding mechanism

Throws:

NoSuchPaddingException - if the requested padding mechanism does not exist

engineGetIV

protected byte[] engineGetIV()

Description copied from class: CipherSpi

Returns the initialization vector (IV) in a new buffer.

This is useful in the context of password-based encryption or decryption, where the IV is derived from a user-provided passphrase.

Specified by:

engineGetIV in class CipherSpi

Returns:

the initialization vector in a new buffer, or null if the underlying algorithm does not use an IV, or if the IV has not yet been set.

engineGetOutputSize

protected int engineGetOutputSize(int in)

Description copied from class: CipherSpi

Returns the length in bytes that an output buffer would need to be in order to hold the result of the next update or doFinal operation, given the input length inputLen (in bytes).

This call takes into account any unprocessed (buffered) data from a previous update call, and padding.

The actual output length of the next update or doFinal call may be smaller than the length returned by this method.

Specified by:

engineGetOutputSize in class CipherSpi

Parameters:

in - the input length (in bytes)

Returns:

the required output buffer size (in bytes)

engineGetParameters

protected java.security.AlgorithmParameters engineGetParameters()

Description copied from class: CipherSpi

Returns the parameters used with this cipher.

The returned parameters may be the same that were used to initialize this cipher, or may contain a combination of default and random parameter values used by the underlying cipher implementation if this cipher requires algorithm parameters but was not initialized with any.

Specified by:

engineGetParameters in class CipherSpi

Returns:

the parameters used with this cipher, or null if this cipher does not use any parameters.

engineInit

protected void engineInit(int mode,
                          java.security.Key key,
                          java.security.SecureRandom r)
                   throws java.security.InvalidKeyException

Description copied from class: CipherSpi

Initializes this cipher with a key and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters that cannot be derived from the given key, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidKeyException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using engineGetParameters or engineGetIV (if the parameter is an IV).

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

Specified by:

engineInit in class CipherSpi

Parameters:

mode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

r - the source of randomness

Throws:

java.security.InvalidKeyException - if the given key is inappropriate for initializing this cipher, or if this cipher is being initialized for decryption and requires algorithm parameters that cannot be determined from the given key.

engineInit

protected void engineInit(int mode,
                          java.security.Key key,
                          java.security.spec.AlgorithmParameterSpec p,
                          java.security.SecureRandom r)
                   throws java.security.InvalidKeyException,
                          java.security.InvalidAlgorithmParameterException

Description copied from class: CipherSpi

Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using engineGetParameters or engineGetIV (if the parameter is an IV).

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

Specified by:

engineInit in class CipherSpi

Parameters:

mode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

p - the algorithm parameters

r - the source of randomness

Throws:

java.security.InvalidKeyException - if the given key is inappropriate for initializing this cipher

java.security.InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialized for decryption and requires algorithm parameters and params is null.

engineInit

protected void engineInit(int mode,
                          java.security.Key key,
                          java.security.AlgorithmParameters p,
                          java.security.SecureRandom r)
                   throws java.security.InvalidKeyException,
                          java.security.InvalidAlgorithmParameterException

Description copied from class: CipherSpi

Initializes this cipher with a key, a set of algorithm parameters, and a source of randomness.

The cipher is initialized for one of the following four operations: encryption, decryption, key wrapping or key unwrapping, depending on the value of opmode.

If this cipher requires any algorithm parameters and params is null, the underlying cipher implementation is supposed to generate the required parameters itself (using provider-specific default or random values) if it is being initialized for encryption or key wrapping, and raise an InvalidAlgorithmParameterException if it is being initialized for decryption or key unwrapping. The generated parameters can be retrieved using engineGetParameters or engineGetIV (if the parameter is an IV).

If this cipher (including its underlying feedback or padding scheme) requires any random bytes (e.g., for parameter generation), it will get them from random.

Note that when a Cipher object is initialized, it loses all previously-acquired state. In other words, initializing a Cipher is equivalent to creating a new instance of that Cipher and initializing it.

Specified by:

engineInit in class CipherSpi

Parameters:

mode - the operation mode of this cipher (this is one of the following: ENCRYPT_MODE, DECRYPT_MODE, WRAP_MODE or UNWRAP_MODE)

key - the encryption key

p - the algorithm parameters

r - the source of randomness

Throws:

java.security.InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this cipher, or if this cipher is being initialized for decryption and requires algorithm parameters and params is null.

java.security.InvalidKeyException - if the given key is inappropriate for initializing this cipher

engineUpdate

protected byte[] engineUpdate(byte[] in,
                              int offset,
                              int length)

Description copied from class: CipherSpi

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in a new buffer.

Specified by:

engineUpdate in class CipherSpi

Parameters:

in - the input buffer

offset - the offset in input where the input starts

length - the input length

Returns:

the new buffer with the result, or null if the underlying cipher is a block cipher and the input data is too short to result in a new block.

engineUpdate

protected int engineUpdate(byte[] in,
                           int inOffset,
                           int length,
                           byte[] out,
                           int outOffset)
                    throws ShortBufferException

Description copied from class: CipherSpi

Continues a multiple-part encryption or decryption operation (depending on how this cipher was initialized), processing another data part.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, are processed, and the result is stored in the output buffer, starting at outputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown.

Specified by:

engineUpdate in class CipherSpi

Parameters:

in - the input buffer

inOffset - the offset in input where the input starts

length - the input length

out - the buffer for the result

outOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

ShortBufferException - if the given output buffer is too small to hold the result

engineDoFinal

protected byte[] engineDoFinal(byte[] in,
                               int offset,
                               int length)
                        throws IllegalBlockSizeException,
                               BadPaddingException

Description copied from class: CipherSpi

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in a new buffer.

A call to this method resets this cipher object to the state it was in when previously initialized via a call to engineInit. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to engineInit) more data.

Specified by:

engineDoFinal in class CipherSpi

Parameters:

in - the input buffer

offset - the offset in input where the input starts

length - the input length

Returns:

the new buffer with the result

Throws:

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size

engineDoFinal

protected int engineDoFinal(byte[] in,
                            int inOffset,
                            int length,
                            byte[] out,
                            int outOffset)
                     throws ShortBufferException,
                            IllegalBlockSizeException,
                            BadPaddingException

Description copied from class: CipherSpi

Encrypts or decrypts data in a single-part operation, or finishes a multiple-part operation. The data is encrypted or decrypted, depending on how this cipher was initialized.

The first inputLen bytes in the input buffer, starting at inputOffset inclusive, and any input bytes that may have been buffered during a previous update operation, are processed, with padding (if requested) being applied. The result is stored in the output buffer, starting at outputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown.

A call to this method resets this cipher object to the state it was in when previously initialized via a call to engineInit. That is, the object is reset and available to encrypt or decrypt (depending on the operation mode that was specified in the call to engineInit) more data.

Specified by:

engineDoFinal in class CipherSpi

Parameters:

in - the input buffer

inOffset - the offset in input where the input starts

length - the input length

out - the buffer for the result

outOffset - the offset in output where the result is stored

Returns:

the number of bytes stored in output

Throws:

ShortBufferException - if the given output buffer is too small to hold the result

BadPaddingException - if this cipher is in decryption mode, and (un)padding has been requested, but the decrypted data is not bounded by the appropriate padding bytes

IllegalBlockSizeException - if this cipher is a block cipher, no padding has been requested (only in encryption mode), and the total input length of the data processed by this cipher is not a multiple of block size