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Class cryptix.provider.cipher.Blowfish

java.lang.Object
   |
   +----java.security.IJCE_Traceable
           |
           +----java.security.Cipher
                   |
                   +----cryptix.provider.cipher.Blowfish

public final class Blowfish
extends Cipher
implements SymmetricCipher
This class implements the Blowfish block cipher.

Blowfish was designed by Bruce Schneier. The algorithm is in the public domain.

References:

  1. Bruce Schneier, "Section 14.3 Blowfish," Applied Cryptography, 2nd edition, John Wiley & Sons, 1996

  2. Bruce Schneier, "Description of a New Variable-Length Key, 64-Bit Cipher (Blowfish)," Fast Software Encryption Cambridge Security Workshop Proceedings, Springer-Verlag, 1004, pp 191-204.

Copyright © 1997 Systemics Ltd on behalf of the Cryptix Development Team.
All rights reserved.

$Revision: 1.5 $

Author:
Systemics Ltd, David Hopwood, Raif S. Naffah

Constructor Index

 o Blowfish()
Constructs a Blowfish cipher object, in the UNINITIALIZED state.

Method Index

 o clone()
Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).
 o engineBlockSize()
SPI: Returns the length of an input block, in bytes.
 o engineGetParameter(String)
SPI: Gets the value of the specified algorithm parameter.
 o engineInitDecrypt(Key)
SPI: Initializes this cipher for decryption, using the specified key.
 o engineInitEncrypt(Key)
SPI: Initializes this cipher for encryption, using the specified key.
 o engineSetParameter(String, Object)
SPI: Sets the specified algorithm parameter to the specified value.
 o engineUpdate(byte[], int, int, byte[], int)
SPI: This is the main engine method for updating data.
 o finalize()
Cleans up resources used by this instance, if necessary.
 o getLinkStatus()
Gets an object representing the native linking status of this class.
 o getRounds()
Returns the currently set number of rounds for this instance.
 o main(String[])
Entry point for very basic self_test.
 o setRounds(int)
Sets the number of rounds for this cipher.

Constructors

 o Blowfish
 public Blowfish()
Constructs a Blowfish cipher object, in the UNINITIALIZED state. This calls the Cipher constructor with implBuffering false, implPadding false and the provider set to "Cryptix".

We define a "rounds" property to allow running the algorithm in a number of rounds different than the default value; i.e. 16. Note however that there is not enough defined initial data for any number of rounds other than 16 for the time being.

Throws: CryptixException
if a CRC check fails on the initial values of the S and P boxes.

Methods

 o getLinkStatus
 public static LinkStatus getLinkStatus()
Gets an object representing the native linking status of this class.

 o finalize
 protected final void finalize()
Cleans up resources used by this instance, if necessary.

Overrides:
finalize in class Object
 o clone
 public final Object clone() throws CloneNotSupportedException
Always throws a CloneNotSupportedException (cloning of ciphers is not supported for security reasons).

Overrides:
clone in class Cipher
 o engineBlockSize
 protected int engineBlockSize()
SPI: Returns the length of an input block, in bytes.

Returns:
the length in bytes of an input block for this cipher.
Overrides:
engineBlockSize in class Cipher
 o engineInitEncrypt
 protected void engineInitEncrypt(Key key) throws InvalidKeyException, CryptixException
SPI: Initializes this cipher for encryption, using the specified key.

Parameters:
key - the key to use for encryption.
Throws: InvalidKeyException
when one of the following occurs:
  • key.getEncoded() == null;
  • The encoded byte array form of the key is zero-length;
  • The length of the user key data array is out of the permissible limits.
Throws: CryptixException
if any one of the two self-tests fail. The two self-tests are as follows:
  1. encrypt 0 ten times using the initial S and P boxes values. Check the result against a known value. If equal decrypt the result 10 times and compare it to 0;
  2. complete the key expansion process and use the newly formed key to encrypt 10 times 0; decrypt the result 10 times and compare.
Overrides:
engineInitEncrypt in class Cipher
 o engineInitDecrypt
 protected void engineInitDecrypt(Key key) throws InvalidKeyException, CryptixException
SPI: Initializes this cipher for decryption, using the specified key.

Parameters:
key - the key to use for decryption.
Throws: InvalidKeyException
when one of the following occurs:
  • key.getEncoded() == null;
  • The encoded byte array form of the key is zero-length;
  • The length of the user key data array is out of the permissible limits.
Throws: CryptixException
if any one of the two self-tests fail. The two self-tests are as follows:
  1. encrypt 0 ten times using the initial S and P boxes values. Check the result against a known value. If equal decrypt the result 10 times and compare it to 0;
  2. complete the key expansion process and use the newly formed key to encrypt 10 times 0; decrypt the result 10 times and compare.
Overrides:
engineInitDecrypt in class Cipher
 o engineUpdate
 protected int engineUpdate(byte in[],
                            int inOffset,
                            int inLen,
                            byte out[],
                            int outOffset)
SPI: This is the main engine method for updating data.

in and out may be the same array, and the input and output regions may overlap.

Parameters:
in - the input data.
inOffset - the offset into in specifying where the data starts.
inLen - the length of the subarray.
out - the output array.
outOffset - the offset indicating where to start writing into the out array.
Returns:
the number of bytes written.
Throws: CryptixException
if the native library is being used, and it reports an error.
Overrides:
engineUpdate in class Cipher
 o engineSetParameter
 protected void engineSetParameter(String param,
                                   Object value) throws InvalidParameterException, InvalidParameterTypeException
SPI: Sets the specified algorithm parameter to the specified value.

Blowfish has a single parameter, "rounds", which specifies the number of rounds for this instance as a decimal String.

Parameters:
param - the string name of the parameter.
value - the parameter value.
Throws: InvalidParameterException
if param is an invalid parameter for this cipher implementation, the parameter is already set and cannot be set again, a security exception occurs, and so on.
Throws: InvalidParameterTypeException
if value is of the wrong type.
Overrides:
engineSetParameter in class Cipher
 o engineGetParameter
 protected Object engineGetParameter(String param)
SPI: Gets the value of the specified algorithm parameter.

Blowfish has a single parameter, "rounds", which specifies the number of rounds for this instance as a decimal String.

Parameters:
param - the string name of the parameter.
Returns:
the object that represents the parameter value, or null if there is none.
Overrides:
engineGetParameter in class Cipher
 o setRounds
 public void setRounds(int r)
Sets the number of rounds for this cipher. Allowed only when this cipher is in the UNINITIALIZED state; otherwise an exception is thrown.

If the specified number is invalid, an IllegalArgumentException is thrown.

Note that there is not enough defined initial data for any number of rounds other than 16 for the time being.

Parameters:
r - the desired number of rounds for this cipher.
Throws: IllegalArgumentException
if the given number of rounds is not supported.
 o getRounds
 public int getRounds()
Returns the currently set number of rounds for this instance.

Returns:
the number of rounds.
 o main
 public static void main(String args[])
Entry point for very basic self_test.


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