xjava.security
public abstract class Mode extends Cipher
Modes are implemented as Ciphers with an additional engine method,
engineSetCipher
, that is called once to set the
underlying cipher algorithm. The Mode class stores this cipher
in the protected field cipher
. Subclasses are expected
to use this to implement their own
engineInitEncrypt
, engineInitDecrypt
and
engineUpdate
methods.
This class is not supported in JavaSoft's version of JCE.
Copyright © 1997
Systemics Ltd on behalf of the
Cryptix Development Team.
All rights reserved.
$Revision: 1.3 $
Since: IJCE 1.0.1
See Also: java.security.Cipher
Field Summary | |
---|---|
protected Cipher | cipher
A reference to the cipher currently operating in this mode. |
Constructor Summary | |
---|---|
protected | Mode(boolean implBuffering, boolean implPadding, String provider)
Constructor for a Mode. |
Method Summary | |
---|---|
protected Object | engineGetParameter(String param)
SPI: Gets the value of the specified algorithm parameter.
|
protected void | engineSetCipher(Cipher cipher)
SPI: Sets the underlying cipher.
|
protected void | engineSetParameter(String param, Object value)
SPI: Sets the specified algorithm parameter to the specified
value.
|
static String[] | getAlgorithms(Provider provider)
Gets the standard names of all Modes implemented by a
provider. |
static String[] | getAlgorithms()
Gets the standard names of all Modes implemented by any
installed provider. |
static Cipher | getInstance(String algorithm)
Generates a Mode object that implements the algorithm
requested, as available in the environment.
|
static Cipher | getInstance(String algorithm, String provider)
Generates a Mode object implementing the specified
algorithm, as supplied from the specified provider, if such an
algorithm is available from the provider.
|
String | toString() |
Cipher.getInstance
factory methods instead.
Parameters: implBuffering if true, this argument indicates that data will be passed from update/crypt to engineUpdate/engineCrypt without modification. implPadding if true, this argument indicates that the implementation can perform padding, and that the engineCrypt method will be called when padding is required. provider the name of the provider of the underlying cryptographic engine.
Throws: NullPointerException if provider == null
This method supplies a general-purpose mechanism through which
it is possible to get the various parameters of this object. The
mode implementation should first check whether it recognizes the
parameter name, and if not, return
super.engineGetParameter(param)
.
A parameter may be any settable parameter for the algorithm, such as block size, a source of random bits for IV generation (if appropriate), or an indication of whether or not to perform a specific but optional computation. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.
The default implementation forwards the call to the underlying cipher.
Parameters: param the string name of the parameter.
Returns: the object that represents the parameter value.
Throws: NoSuchParameterException if there is no parameter with name param for this cipher implementation. InvalidParameterException if the parameter exists but cannot be read.
For example, to create an IDEA cipher in CBC mode, the cipher for "IDEA" would be passed to the mode for "CBC" using this method. It is called once, immediately after the mode object is constructed.
Subclasses that override this method (to do initialization that
depends on the cipher being set) should call
super.engineSetCipher(cipher)
first.
Parameters: cipher the underlying cipher object
Throws: NullPointerException if cipher == null
This method supplies a general-purpose mechanism through which it is
possible to set the various parameters of this object. The mode
implementation should first check whether it recognizes the
parameter name, and if not, call
super.engineSetParameter(param, value)
.
A parameter may be any settable parameter for the algorithm, such as block size, a source of random bits for IV generation (if appropriate), or an indication of whether or not to perform a specific but optional computation. A uniform algorithm-specific naming scheme for each parameter is desirable but left unspecified at this time.
The default implementation forwards the call to the underlying cipher.
Parameters: param the string name of the parameter. value the parameter value.
Throws: NoSuchParameterException if there is no parameter with name param for this cipher implementation. InvalidParameterException if the parameter exists but cannot be set (for example because the cipher is in the wrong state). InvalidParameterTypeException if value is the wrong type for this parameter.
See International JCE Standard Algorithm Names for a list of Mode algorithm names.
Parameters: algorithm the standard name or an alias for the algorithm.
Returns: the new Mode object.
Throws: NoSuchAlgorithmException if the algorithm is not available in the environment.
See International JCE Standard Algorithm Names for a list of Mode algorithm names.
Parameters: algorithm the standard name or an alias for the algorithm. provider the string name of the provider.
Returns: the new KeyGenerator object.
Throws: NoSuchAlgorithmException if the algorithm is not available from the provider. NoSuchProviderException if the provider is not available in the environment.