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Class cryptix.provider.cipher.Blowfish
java.lang.Object
|
+----java.security.IJCE_Traceable
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+----java.security.Cipher
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+----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:
- Bruce Schneier,
"Section 14.3 Blowfish,"
Applied Cryptography, 2nd edition,
John Wiley & Sons, 1996
- 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
-
Blowfish()
- Constructs a Blowfish cipher object, in the UNINITIALIZED state.
-
clone()
- Always throws a CloneNotSupportedException (cloning of ciphers is not
supported for security reasons).
-
engineBlockSize()
- SPI: Returns the length of an input block, in bytes.
-
engineGetParameter(String)
- SPI: Gets the value of the specified algorithm parameter.
-
engineInitDecrypt(Key)
- SPI: Initializes this cipher for decryption, using the
specified key.
-
engineInitEncrypt(Key)
- SPI: Initializes this cipher for encryption, using the
specified key.
-
engineSetParameter(String, Object)
- SPI: Sets the specified algorithm parameter to the specified
value.
-
engineUpdate(byte[], int, int, byte[], int)
- SPI: This is the main engine method for updating data.
-
finalize()
- Cleans up resources used by this instance, if necessary.
-
getLinkStatus()
- Gets an object representing the native linking status of this class.
-
getRounds()
- Returns the currently set number of rounds for this instance.
-
main(String[])
- Entry point for very basic
self_test
.
-
setRounds(int)
- Sets the number of rounds for this cipher.
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.
getLinkStatus
public static LinkStatus getLinkStatus()
- Gets an object representing the native linking status of this class.
finalize
protected final void finalize()
- Cleans up resources used by this instance, if necessary.
- Overrides:
- finalize in class Object
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
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
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:
- 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;
- 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
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:
- 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;
- 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
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
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
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
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.
getRounds
public int getRounds()
- Returns the currently set number of rounds for this instance.
- Returns:
- the number of rounds.
main
public static void main(String args[])
- Entry point for very basic
self_test
.
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