xjava.security

Interface ExtendedKeyGenerator

public interface ExtendedKeyGenerator

The KeyGenerator class in JavaSoft's original version of JCE does not provide these essential features:

This interface provides a standard API for KeyGenerators that implement the above features.

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

$Revision: 1.2 $

Since: IJCE 1.0.1

Author: David Hopwood Raif S. Naffah

Method Summary
SecretKeygenerateKey()
Generates a key.
SecretKeygenerateKey(byte[] data)
Generates a key from an encoded byte array.
intgetDefaultKeyLength()
Returns the key length that will be used by generateKey() to create new random keys.
intgetMaximumKeyLength()
Returns the maximum useful key length for this algorithm.
intgetMinimumKeyLength()
Returns the minimum key length for this algorithm.
voidinitialize(SecureRandom random)
Initializes the key generator.
voidinitialize(SecureRandom random, int length)
Initializes the key generator, and sets a specific key length for use with algorithms that allow variable-length keys.
booleanisValidKeyLength(int length)
Returns true iff length is a valid key length (in bytes) for this algorithm.
booleanisWeakAllowed()
Returns true if this object is allowed to generate weak and semi-weak keys; false otherwise.
voidsetWeakAllowed(boolean allowWeak)
Sets whether this object is allowed to generate weak and semi-weak keys.

Method Detail

generateKey

public SecretKey generateKey()
Generates a key. This method generates a new random key every time it is called.

If a source of random bytes has not been set using one of the initialize methods, new SecureRandom() will be used.

Returns: the new key.

generateKey

public SecretKey generateKey(byte[] data)
Generates a key from an encoded byte array. The format of the secret key is "RAW". The contents of data will not be modified.

The encoded key bytes may differ from data in order to make sure that they represent a valid key. For example, if keys for this algorithm conventionally include parity bits, those bits will be set correctly. For most algorithms, data is used unchanged.

Parameters: data user supplied raw-encoded data from which a secret key will be generated.

Returns: the new key.

Throws: NullPointerException if data == null WeakKeyException if isWeakAllowed() is false, and data represents a weak key for this algorithm. InvalidKeyException if the length of data is not valid for this algorithm.

getDefaultKeyLength

public int getDefaultKeyLength()
Returns the key length that will be used by generateKey() to create new random keys. This is either the default key length determined by the KeyGenerator for this algorithm, or the length set using initialize(SecureRandom random, int length).

getMaximumKeyLength

public int getMaximumKeyLength()
Returns the maximum useful key length for this algorithm.

getMinimumKeyLength

public int getMinimumKeyLength()
Returns the minimum key length for this algorithm.

initialize

public void initialize(SecureRandom random)
Initializes the key generator.

Parameters: random the source of randomness for this generator.

initialize

public void initialize(SecureRandom random, int length)
Initializes the key generator, and sets a specific key length for use with algorithms that allow variable-length keys.

The length parameter only affects randomly generated keys (i.e. the generateKey() method without parameters).

Parameters: random the source of randomness for this generator. length the desired key length in bytes.

Throws: IllegalArgumentException if length is not valid for this algorithm.

isValidKeyLength

public boolean isValidKeyLength(int length)
Returns true iff length is a valid key length (in bytes) for this algorithm.

isWeakAllowed

public boolean isWeakAllowed()
Returns true if this object is allowed to generate weak and semi-weak keys; false otherwise.

setWeakAllowed

public void setWeakAllowed(boolean allowWeak)
Sets whether this object is allowed to generate weak and semi-weak keys.

Parameters: allowWeak true if weak/semi-weak keys are allowed.