org.bouncycastle.pqc.crypto.gmss.GMSSParameters Maven / Gradle / Ivy
package org.bouncycastle.pqc.crypto.gmss;
import org.bouncycastle.util.Arrays;
/**
* This class provides a specification for the GMSS parameters that are used by
* the GMSSKeyPairGenerator and GMSSSignature classes.
*
* @see org.bouncycastle.pqc.crypto.gmss.GMSSKeyPairGenerator
*/
public class GMSSParameters
{
/**
* The number of authentication tree layers.
*/
private int numOfLayers;
/**
* The height of the authentication trees of each layer.
*/
private int[] heightOfTrees;
/**
* The Winternitz Parameter 'w' of each layer.
*/
private int[] winternitzParameter;
/**
* The parameter K needed for the authentication path computation
*/
private int[] K;
/**
* The constructor for the parameters of the GMSSKeyPairGenerator.
*
* @param layers the number of authentication tree layers
* @param heightOfTrees the height of the authentication trees
* @param winternitzParameter the Winternitz Parameter 'w' of each layer
* @param K parameter for authpath computation
*/
public GMSSParameters(int layers, int[] heightOfTrees, int[] winternitzParameter, int[] K)
throws IllegalArgumentException
{
init(layers, heightOfTrees, winternitzParameter, K);
}
private void init(int layers, int[] heightOfTrees,
int[] winternitzParameter, int[] K)
throws IllegalArgumentException
{
boolean valid = true;
String errMsg = "";
this.numOfLayers = layers;
if ((numOfLayers != winternitzParameter.length)
|| (numOfLayers != heightOfTrees.length)
|| (numOfLayers != K.length))
{
valid = false;
errMsg = "Unexpected parameterset format";
}
for (int i = 0; i < numOfLayers; i++)
{
if ((K[i] < 2) || ((heightOfTrees[i] - K[i]) % 2 != 0))
{
valid = false;
errMsg = "Wrong parameter K (K >= 2 and H-K even required)!";
}
if ((heightOfTrees[i] < 4) || (winternitzParameter[i] < 2))
{
valid = false;
errMsg = "Wrong parameter H or w (H > 3 and w > 1 required)!";
}
}
if (valid)
{
this.heightOfTrees = Arrays.clone(heightOfTrees);
this.winternitzParameter = Arrays.clone(winternitzParameter);
this.K = Arrays.clone(K);
}
else
{
throw new IllegalArgumentException(errMsg);
}
}
public GMSSParameters(int keySize)
throws IllegalArgumentException
{
if (keySize <= 10)
{ // create 2^10 keys
int[] defh = {10};
int[] defw = {3};
int[] defk = {2};
this.init(defh.length, defh, defw, defk);
}
else if (keySize <= 20)
{ // create 2^20 keys
int[] defh = {10, 10};
int[] defw = {5, 4};
int[] defk = {2, 2};
this.init(defh.length, defh, defw, defk);
}
else
{ // create 2^40 keys, keygen lasts around 80 seconds
int[] defh = {10, 10, 10, 10};
int[] defw = {9, 9, 9, 3};
int[] defk = {2, 2, 2, 2};
this.init(defh.length, defh, defw, defk);
}
}
/**
* Returns the number of levels of the authentication trees.
*
* @return The number of levels of the authentication trees.
*/
public int getNumOfLayers()
{
return numOfLayers;
}
/**
* Returns the array of height (for each layer) of the authentication trees
*
* @return The array of height (for each layer) of the authentication trees
*/
public int[] getHeightOfTrees()
{
return Arrays.clone(heightOfTrees);
}
/**
* Returns the array of WinternitzParameter (for each layer) of the
* authentication trees
*
* @return The array of WinternitzParameter (for each layer) of the
* authentication trees
*/
public int[] getWinternitzParameter()
{
return Arrays.clone(winternitzParameter);
}
/**
* Returns the parameter K needed for authentication path computation
*
* @return The parameter K needed for authentication path computation
*/
public int[] getK()
{
return Arrays.clone(K);
}
}