public final class CAST5 extends Cipher implements SymmetricCipher
In this RFC, Carlisle Adams (the CA in CAST, ST standing for Stafford Tavares) describes CAST5 as:
"...a DES-like Substitution-Permutation Network (SPN) cryptosystem which appears to have good resistance to differential cryptanalysis, linear cryptanalysis, and related-key cryptanalysis. This cipher also possesses a number of other desirable cryptographic properties, including avalanche, Strict Avalanche Criterion (SAC), Bit Independence Criterion (BIC), no complementation property, and an absence of weak and semi-weak keys."
CAST5 is a symmetric block cipher with a block-size of 8 bytes and a variable key-size of up to 128 bits. Its authors and their employer (Entrust Technologies, a Nortel majority-owned company) made it available worldwide on a royalty-free basis for commercial and non-commercial uses.
The CAST5 encryption algorithm has been designed to allow a key size that can vary from 40 bits to 128 bits, in 8-bit increments (that is, the allowable key sizes are 40, 48, 56, 64, ..., 112, 120, and 128 bits. For variable keysize operation, the specification is as follows:
References:
Copyright © 1997
Systemics Ltd on behalf of the
Cryptix Development Team.
All rights reserved.
$Revision: 1.6 $
DECRYPT, ENCRYPT, UNINITIALIZED
Constructor and Description |
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CAST5()
Constructs a CAST5 cipher object, in the UNINITIALIZED state.
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Modifier and Type | Method and Description |
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java.lang.Object |
clone()
Always throws a CloneNotSupportedException (cloning of ciphers is not
supported for security reasons).
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protected int |
engineBlockSize()
SPI: Returns the length of an input block, in bytes.
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protected void |
engineInitDecrypt(java.security.Key key)
SPI: Initializes this cipher for decryption, using the
specified key.
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protected void |
engineInitEncrypt(java.security.Key key)
SPI: Initializes this cipher for encryption, using the
specified key.
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protected int |
engineUpdate(byte[] in,
int inOffset,
int inLen,
byte[] out,
int outOffset)
SPI: This is the main engine method for updating data.
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protected void |
finalize()
Cleans up resources used by this instance, if necessary.
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static LinkStatus |
getLinkStatus()
Gets an object representing the native linking status of this class.
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blockSize, crypt, crypt, crypt, doFinal, doFinal, doFinal, doFinal, engineCiphertextBlockSize, engineCrypt, engineGetParameter, engineInBufferSize, engineOutBufferSize, enginePlaintextBlockSize, engineSetPaddingScheme, engineSetParameter, getAlgorithm, getAlgorithms, getAlgorithms, getCiphertextBlockSize, getInputBlockSize, getInstance, getInstance, getInstance, getMode, getOutputBlockSize, getPadding, getPaddingScheme, getParameter, getPlaintextBlockSize, getProvider, getState, inBufferSize, inBufferSizeFinal, initDecrypt, initEncrypt, isPaddingBlockCipher, outBufferSize, outBufferSizeFinal, setParameter, toString, update, update, update, update
public CAST5()
java.security.Cipher#UNINITIALIZED
public static LinkStatus getLinkStatus()
protected final void finalize()
finalize
in class java.lang.Object
public final java.lang.Object clone() throws java.lang.CloneNotSupportedException
protected int engineBlockSize()
engineBlockSize
in class Cipher
protected void engineInitEncrypt(java.security.Key key) throws java.security.KeyException
engineInitEncrypt
in class Cipher
key
- the key to use for encryption.java.security.KeyException
- when one of the following occurs:protected void engineInitDecrypt(java.security.Key key) throws java.security.KeyException
engineInitDecrypt
in class Cipher
key
- the key to use for decryption.java.security.KeyException
- when one of the following occurs:protected int engineUpdate(byte[] in, int inOffset, int inLen, byte[] out, int outOffset)
in and out may be the same array, and the input and output regions may overlap.
engineUpdate
in class Cipher
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.CryptixException
- if the native library is being used, and it
reports an error.