public class UMacGenerator
extends tr.gov.tubitak.uekae.esya.api.common.crypto.BasePRNG
KDFs (Key Derivation Functions) are used to stretch user-supplied key material to specific size(s) required by high level cryptographic primitives. Described in the UMAC paper, this function basically operates an underlying symmetric key block cipher instance in output feedback mode (OFB), as a strong pseudo-random number generator.
UMacGenerator
requires an index parameter
(initialisation parameter gnu.crypto.prng.umac.kdf.index
taken
to be an instance of Integer
with a value between
0
and 255
). Using the same key, but different
indices, generates different pseudorandom outputs.
This implementation generalises the definition of the
UmacGenerator
algorithm to allow for other than the AES symetric
key block cipher algorithm (initialisation parameter
gnu.crypto.prng.umac.cipher.name
taken to be an instance of
String
). If such a parameter is not defined/included in the
initialisation Map
, then the "Rijndael" algorithm is used.
Furthermore, if the initialisation parameter
gnu.crypto.cipher.block.size
(taken to be a instance of Integer
) is missing or undefined in the initialisation Map
, then the cipher's default block size is used.
NOTE: Rijndael is used as the default symmetric key block cipher algorithm because, with its default block and key sizes, it is the AES. Yet being Rijndael, the algorithm offers more versatile block and key sizes which may prove to be useful for generating "longer" key streams.
References:
Modifier and Type | Field and Description |
---|---|
static java.lang.String |
CIPHER
The name of the underlying symmetric key block cipher algorithm.
|
static java.lang.String |
INDEX
Property name of the KDF
index value to use in this
instance. |
Constructor and Description |
---|
UMacGenerator()
Trivial 0-arguments constructor.
|
Modifier and Type | Method and Description |
---|---|
java.lang.Object |
clone() |
void |
fillBlock() |
void |
setup(java.util.Map attributes) |
public static final java.lang.String INDEX
Property name of the KDF index
value to use in this
instance. The value is taken to be an Integer
less than
256
.
public static final java.lang.String CIPHER
public java.lang.Object clone()
clone
in interface tr.gov.tubitak.uekae.esya.api.common.crypto.IRandom
clone
in class tr.gov.tubitak.uekae.esya.api.common.crypto.BasePRNG
public void setup(java.util.Map attributes)
setup
in class tr.gov.tubitak.uekae.esya.api.common.crypto.BasePRNG
public void fillBlock() throws tr.gov.tubitak.uekae.esya.api.common.crypto.LimitReachedException
fillBlock
in class tr.gov.tubitak.uekae.esya.api.common.crypto.BasePRNG
tr.gov.tubitak.uekae.esya.api.common.crypto.LimitReachedException
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