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Class cryptix.provider.cipher.SAFER
java.lang.Object
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+----java.security.IJCE_Traceable
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+----java.security.Cipher
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+----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:
- 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.
- 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.
- 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
-
K128_VARIANT
-
-
K64_VARIANT
-
-
SK128_VARIANT
-
-
SK64_VARIANT
-
-
SAFER()
- Calls the Cipher constructor with
implBuffering
false,
implPadding
false and the provider set to "Cryptix".
-
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()
- Gets the number of rounds for this cipher.
-
getVariant()
- Gets the variant for this cipher ("SK-128", "SK-64", "K-128", or "K-64").
-
setRounds(int)
- Sets the number of rounds for this cipher.
-
setVariant(String)
- Sets the variant for this cipher.
SK128_VARIANT
public static final int SK128_VARIANT
SK64_VARIANT
public static final int SK64_VARIANT
K128_VARIANT
public static final int K128_VARIANT
K64_VARIANT
public static final int K64_VARIANT
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:
- SK-128, SK128, sk-128 and sk128: Strengthened key schedule of
length 128 bits.
- SK-64, SK64, sk-64 and sk64: Strengthened key schedule of
length 64 bits.
- K-128, K128, k-128 and k128: Non-strengthened key schedule of
length 128 bits.
- K-64, K64, k-64 and k64: Non-strengthened key schedule of length
64 bits.
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.
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
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
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
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
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 NoSuchParameterException, InvalidParameterException, InvalidParameterTypeException
- SPI: Sets the specified algorithm parameter to the specified
value.
- Overrides:
- engineSetParameter in class Cipher
engineGetParameter
protected Object engineGetParameter(String param) throws NoSuchParameterException, InvalidParameterException
- SPI: Gets the value of the specified algorithm parameter.
- Overrides:
- engineGetParameter in class Cipher
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.
getRounds
public int getRounds()
- Gets the number of rounds for this cipher.
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.
getVariant
public String getVariant()
- Gets the variant for this cipher ("SK-128", "SK-64", "K-128", or "K-64").
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