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Class au.net.aba.crypto.provider.DESMac
java.lang.Object
|
+----javax.crypto.MacSpi
|
+----au.net.aba.crypto.provider.DESMac
- public class DESMac
- extends MacSpi
This class implements the DES based MAC algorithm as defined in
FIPS PUB 113.
This algorithm produces a 4 byte MAC value.
Currently this class will not work correctly unless the input data
size is an exact multiple of 8. Data that isnt of this length
should be padded with zeros. Eventually the DES cipher class
will be modified to perform this function.
-
DESMac()
- Default constructor, initialises the instance.
-
engineDoFinal()
- Completes the MAC computation and resets the MAC for further
use, maintaining the secret key that the MAC was initialised with.
-
engineGetMacLength()
- Returns the length of the MAC in bytes.
-
engineInit(Key, AlgorithmParameterSpec)
- Initialises the MAC with the given (secret) key and algorithm
parameters.
-
engineReset()
- Resets the MAC for further use, maintaining the secret key that
the MAC was initialised with.
-
engineUpdate(byte)
- Processes the given byte.
-
engineUpdate(byte[], int, int)
- Processes the first len bytes in input, starting at offset.
DESMac
public DESMac()
- Default constructor, initialises the instance.
engineGetMacLength
protected int engineGetMacLength()
- Returns the length of the MAC in bytes.
- Returns:
- the MAC length in bytes.
- Overrides:
- engineGetMacLength in class MacSpi
engineInit
protected void engineInit(Key key,
AlgorithmParameterSpec params) throws InvalidKeyException, InvalidAlgorithmParameterException
- Initialises the MAC with the given (secret) key and algorithm
parameters. The
key
parameter should be a
type that is compatible with the DES Cipher
.
- Parameters:
- key - the (secret) key.
- params - the algorithm parameters.
- Throws: InvalidKeyException
- if the given key is inappropriate for
initialising this MAC.
- Throws: InvalidAlgorithmParameterException
- if the given algorithm
parameters are inappropriate for this MAC.
- Overrides:
- engineInit in class MacSpi
engineUpdate
protected void engineUpdate(byte input)
- Processes the given byte.
- Parameters:
- input - the input byte to be processed.
- Overrides:
- engineUpdate in class MacSpi
engineUpdate
protected void engineUpdate(byte input[],
int offset,
int len)
- Processes the first len bytes in input, starting at offset.
- Parameters:
- input - the input buffer.
- offset - the offset in input where the input starts.
- len - the number of bytes to process.
- Overrides:
- engineUpdate in class MacSpi
engineDoFinal
protected byte[] engineDoFinal()
- Completes the MAC computation and resets the MAC for further
use, maintaining the secret key that the MAC was initialised with.
- Returns:
- the MAC result.
- Overrides:
- engineDoFinal in class MacSpi
engineReset
protected void engineReset()
- Resets the MAC for further use, maintaining the secret key that
the MAC was initialised with.
- Overrides:
- engineReset in class MacSpi
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