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Class cryptix.provider.cipher.SAFER

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

public final class SAFER
extends Cipher
implements SymmetricCipher
A subclass of Cipher to implement the SAFER algorithm in Java.

SAFER (Secure And Fast Encryption Routine) is a block-cipher algorithm developed by Prof. J.L. Massey at the Swiss Federal Institute of Technology. SAFER is usable in four versions (referred to in this implementation as VARIANTS): SAFER K-64, SAFER K-128, SAFER SK-64 and SAFER SK-128. The numerals 64 and 128 stand for the length of the user-selected key, 'K' stands for the original key schedule and 'SK' stands for the strengthened key schedule.

References:

  1. Massey, J.L., "SAFER K-64: A Byte-Oriented Block Ciphering Algorithm", pp. 1-17 in Fast Software Encryption (Ed. R. Anderson), Proceedings of the Cambridge Security Workshop, Cambridge, U.K., December 9-11, 1993,
    Lecture Notes in Computer Science No. 809. Heidelberg and New York: Springer, 1994.

  2. Massey, J.L., "SAFER K-64: One Year Later", preliminary manuscript of a paper presented at the K. U. Leuven Workshop on Cryptographic Algorithms, December 14-16, 1994.
    To be published in the Proceedings of this workshop by Springer.

  3. Massey, J.L., "Announcement of a Strengthened Key Schedule for the Cipher SAFER", Sept. 9, 1995, (see file 'SAFER_SK.TXT' included in the Richard De Moliner C-code distribution).

Ported to Java from public domain 'C' code latest revised on September 9, 1995 by:

Richard De Moliner (demoliner@isi.ee.ethz.ch)
Signal and Information Processing Laboratory
Swiss Federal Institute of Technology
CH-8092 Zürich, Switzerland.

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

$Revision: 1.5 $

Author:
Raif S. Naffah, David Hopwood

Variable Index

 o K128_VARIANT
 o K64_VARIANT
 o SK128_VARIANT
 o SK64_VARIANT

Constructor Index

 o SAFER()
Calls the Cipher constructor with implBuffering false, implPadding false and the provider set to "Cryptix".

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()
Gets the number of rounds for this cipher.
 o getVariant()
Gets the variant for this cipher ("SK-128", "SK-64", "K-128", or "K-64").
 o setRounds(int)
Sets the number of rounds for this cipher.
 o setVariant(String)
Sets the variant for this cipher.

Variables

 o SK128_VARIANT
 public static final int SK128_VARIANT
 o SK64_VARIANT
 public static final int SK64_VARIANT
 o K128_VARIANT
 public static final int K128_VARIANT
 o K64_VARIANT
 public static final int K64_VARIANT

Constructors

 o SAFER
 public SAFER()
Calls the Cipher constructor with implBuffering false, implPadding false and the provider set to "Cryptix".

Sets the variant of this cipher based on the currently set "variant" property in the provider properties file. The current JCE syntax for the SAFER algorithm variant property is:

    Alg.variant.SAFER = ...
 

Valid alternatives for variant are:

Once the variant is set, a default value for the number of rounds to use is also set as follows:

    Variant   Number of rounds = current value
    -------   --------------------------------
    SK-128    SK128_DEFAULT_NOF_ROUNDS = 10
    SK-64     SK64_DEFAULT_NOF_ROUNDS  =  8
    K-128     K128_DEFAULT_NOF_ROUNDS  = 10
    K-64      K64_DEFAULT_NOF_ROUNDS   =  6
 

If no variant property is found in the provider's properties file a strengthened key schedule of 128 bits is used with 10 rounds.

This constructor also attempts to set the desired number of rounds for this cipher object from a "rounds" property in the provider's properties file. Acceptable values are non-zero integers between 1 and the MAX_NOF_ROUNDS constant; i.e. 13. If no such property is found, or is found but deemed invalid, then the already set value (depending on the variant property as determined above) remains unaltered.

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
 public 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
 public void engineInitEncrypt(Key key) throws KeyException
SPI: Initializes this cipher for encryption, using the specified key.

Parameters:
key - the key to use for encryption.
Throws: KeyException
if the key is invalid.
Overrides:
engineInitEncrypt in class Cipher
 o engineInitDecrypt
 public void engineInitDecrypt(Key key) throws KeyException
SPI: Initializes this cipher for decryption, using the specified key.

Parameters:
key - the key to use for decryption.
Throws: KeyException
if the key is invalid.
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 NoSuchParameterException, InvalidParameterException, InvalidParameterTypeException
SPI: Sets the specified algorithm parameter to the specified value.

Overrides:
engineSetParameter in class Cipher
 o engineGetParameter
 protected Object engineGetParameter(String param) throws NoSuchParameterException, InvalidParameterException
SPI: Gets the value of the specified algorithm parameter.

Overrides:
engineGetParameter in class Cipher
 o setRounds
 public void setRounds(int rounds)
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, the current one remains unchanged.

Parameters:
rounds - the desired number of rounds for this cipher.
 o getRounds
 public int getRounds()
Gets the number of rounds for this cipher.

 o setVariant
 public void setVariant(String ps)
Sets the variant for this cipher. Allowed only when this cipher is in the UNINITIALIZED state; otherwise an exception is thrown.

Parameters:
ps - The desired new variant identifier for this cipher.
 o getVariant
 public String getVariant()
Gets the variant for this cipher ("SK-128", "SK-64", "K-128", or "K-64").


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