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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 and up.
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package org.bouncycastle.pqc.crypto.gmss;
import java.util.Vector;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.pqc.crypto.gmss.util.GMSSRandom;
import org.bouncycastle.pqc.crypto.gmss.util.WinternitzOTSignature;
import org.bouncycastle.util.Arrays;
/**
* This class provides a specification for a GMSS private key.
*/
public class GMSSPrivateKeyParameters
extends GMSSKeyParameters
{
private int[] index;
private byte[][] currentSeeds;
private byte[][] nextNextSeeds;
private byte[][][] currentAuthPaths;
private byte[][][] nextAuthPaths;
private Treehash[][] currentTreehash;
private Treehash[][] nextTreehash;
private Vector[] currentStack;
private Vector[] nextStack;
private Vector[][] currentRetain;
private Vector[][] nextRetain;
private byte[][][] keep;
private GMSSLeaf[] nextNextLeaf;
private GMSSLeaf[] upperLeaf;
private GMSSLeaf[] upperTreehashLeaf;
private int[] minTreehash;
private GMSSParameters gmssPS;
private byte[][] nextRoot;
private GMSSRootCalc[] nextNextRoot;
private byte[][] currentRootSig;
private GMSSRootSig[] nextRootSig;
private GMSSDigestProvider digestProvider;
private boolean used = false;
/**
* An array of the heights of the authentication trees of each layer
*/
private int[] heightOfTrees;
/**
* An array of the Winternitz parameter 'w' of each layer
*/
private int[] otsIndex;
/**
* The parameter K needed for the authentication path computation
*/
private int[] K;
/**
* the number of Layers
*/
private int numLayer;
/**
* The hash function used to construct the authentication trees
*/
private Digest messDigestTrees;
/**
* The message digest length
*/
private int mdLength;
/**
* The PRNG used for private key generation
*/
private GMSSRandom gmssRandom;
/**
* The number of leafs of one tree of each layer
*/
private int[] numLeafs;
/**
* Generates a new GMSS private key
*
* @param currentSeed seed for the generation of private OTS keys for the
* current subtrees
* @param nextNextSeed seed for the generation of private OTS keys for the next
* subtrees
* @param currentAuthPath array of current authentication paths
* @param nextAuthPath array of next authentication paths
* @param currentTreehash array of current treehash instances
* @param nextTreehash array of next treehash instances
* @param currentStack array of current shared stacks
* @param nextStack array of next shared stacks
* @param currentRetain array of current retain stacks
* @param nextRetain array of next retain stacks
* @param nextRoot the roots of the next subtree
* @param currentRootSig array of signatures of the roots of the current subtrees
* @param gmssParameterset the GMSS Parameterset
* @see org.bouncycastle.pqc.crypto.gmss.GMSSKeyPairGenerator
*/
public GMSSPrivateKeyParameters(byte[][] currentSeed, byte[][] nextNextSeed,
byte[][][] currentAuthPath, byte[][][] nextAuthPath,
Treehash[][] currentTreehash, Treehash[][] nextTreehash,
Vector[] currentStack, Vector[] nextStack,
Vector[][] currentRetain, Vector[][] nextRetain, byte[][] nextRoot,
byte[][] currentRootSig, GMSSParameters gmssParameterset,
GMSSDigestProvider digestProvider)
{
this(null, currentSeed, nextNextSeed, currentAuthPath, nextAuthPath,
null, currentTreehash, nextTreehash, currentStack, nextStack,
currentRetain, nextRetain, null, null, null, null, nextRoot,
null, currentRootSig, null, gmssParameterset, digestProvider);
}
/**
* /**
*
* @param index tree indices
* @param keep keep array for the authPath algorithm
* @param currentTreehash treehash for authPath algorithm of current tree
* @param nextTreehash treehash for authPath algorithm of next tree (TREE+)
* @param currentStack shared stack for authPath algorithm of current tree
* @param nextStack shared stack for authPath algorithm of next tree (TREE+)
* @param currentRetain retain stack for authPath algorithm of current tree
* @param nextRetain retain stack for authPath algorithm of next tree (TREE+)
* @param nextNextLeaf array of upcoming leafs of the tree after next (LEAF++) of
* each layer
* @param upperLeaf needed for precomputation of upper nodes
* @param upperTreehashLeaf needed for precomputation of upper treehash nodes
* @param minTreehash index of next treehash instance to receive an update
* @param nextRoot the roots of the next trees (ROOT+)
* @param nextNextRoot the roots of the tree after next (ROOT++)
* @param currentRootSig array of signatures of the roots of the current subtrees
* (SIG)
* @param nextRootSig array of signatures of the roots of the next subtree
* (SIG+)
* @param gmssParameterset the GMSS Parameterset
*/
public GMSSPrivateKeyParameters(int[] index, byte[][] currentSeeds,
byte[][] nextNextSeeds, byte[][][] currentAuthPaths,
byte[][][] nextAuthPaths, byte[][][] keep,
Treehash[][] currentTreehash, Treehash[][] nextTreehash,
Vector[] currentStack, Vector[] nextStack,
Vector[][] currentRetain, Vector[][] nextRetain,
GMSSLeaf[] nextNextLeaf, GMSSLeaf[] upperLeaf,
GMSSLeaf[] upperTreehashLeaf, int[] minTreehash, byte[][] nextRoot,
GMSSRootCalc[] nextNextRoot, byte[][] currentRootSig,
GMSSRootSig[] nextRootSig, GMSSParameters gmssParameterset,
GMSSDigestProvider digestProvider)
{
super(true, gmssParameterset);
// construct message digest
this.messDigestTrees = digestProvider.get();
this.mdLength = messDigestTrees.getDigestSize();
// Parameter
this.gmssPS = gmssParameterset;
this.otsIndex = gmssParameterset.getWinternitzParameter();
this.K = gmssParameterset.getK();
this.heightOfTrees = gmssParameterset.getHeightOfTrees();
// initialize numLayer
this.numLayer = gmssPS.getNumOfLayers();
// initialize index if null
if (index == null)
{
this.index = new int[numLayer];
for (int i = 0; i < numLayer; i++)
{
this.index[i] = 0;
}
}
else
{
this.index = index;
}
this.currentSeeds = currentSeeds;
this.nextNextSeeds = nextNextSeeds;
this.currentAuthPaths = Arrays.clone(currentAuthPaths);
this.nextAuthPaths = nextAuthPaths;
// initialize keep if null
if (keep == null)
{
this.keep = new byte[numLayer][][];
for (int i = 0; i < numLayer; i++)
{
this.keep[i] = new byte[(int)Math.floor(heightOfTrees[i] / 2)][mdLength];
}
}
else
{
this.keep = keep;
}
// initialize stack if null
if (currentStack == null)
{
this.currentStack = new Vector[numLayer];
for (int i = 0; i < numLayer; i++)
{
this.currentStack[i] = new Vector();
}
}
else
{
this.currentStack = currentStack;
}
// initialize nextStack if null
if (nextStack == null)
{
this.nextStack = new Vector[numLayer - 1];
for (int i = 0; i < numLayer - 1; i++)
{
this.nextStack[i] = new Vector();
}
}
else
{
this.nextStack = nextStack;
}
this.currentTreehash = currentTreehash;
this.nextTreehash = nextTreehash;
this.currentRetain = currentRetain;
this.nextRetain = nextRetain;
this.nextRoot = nextRoot;
this.digestProvider = digestProvider;
if (nextNextRoot == null)
{
this.nextNextRoot = new GMSSRootCalc[numLayer - 1];
for (int i = 0; i < numLayer - 1; i++)
{
this.nextNextRoot[i] = new GMSSRootCalc(
this.heightOfTrees[i + 1], this.K[i + 1], this.digestProvider);
}
}
else
{
this.nextNextRoot = nextNextRoot;
}
this.currentRootSig = currentRootSig;
// calculate numLeafs
numLeafs = new int[numLayer];
for (int i = 0; i < numLayer; i++)
{
numLeafs[i] = 1 << heightOfTrees[i];
}
// construct PRNG
this.gmssRandom = new GMSSRandom(messDigestTrees);
if (numLayer > 1)
{
// construct the nextNextLeaf (LEAFs++) array for upcoming leafs in
// tree after next (TREE++)
if (nextNextLeaf == null)
{
this.nextNextLeaf = new GMSSLeaf[numLayer - 2];
for (int i = 0; i < numLayer - 2; i++)
{
this.nextNextLeaf[i] = new GMSSLeaf(digestProvider.get(), otsIndex[i + 1], numLeafs[i + 2], this.nextNextSeeds[i]);
}
}
else
{
this.nextNextLeaf = nextNextLeaf;
}
}
else
{
this.nextNextLeaf = new GMSSLeaf[0];
}
// construct the upperLeaf array for upcoming leafs in tree over the
// actual
if (upperLeaf == null)
{
this.upperLeaf = new GMSSLeaf[numLayer - 1];
for (int i = 0; i < numLayer - 1; i++)
{
this.upperLeaf[i] = new GMSSLeaf(digestProvider.get(), otsIndex[i],
numLeafs[i + 1], this.currentSeeds[i]);
}
}
else
{
this.upperLeaf = upperLeaf;
}
// construct the leafs for upcoming leafs in treehashs in tree over the
// actual
if (upperTreehashLeaf == null)
{
this.upperTreehashLeaf = new GMSSLeaf[numLayer - 1];
for (int i = 0; i < numLayer - 1; i++)
{
this.upperTreehashLeaf[i] = new GMSSLeaf(digestProvider.get(), otsIndex[i], numLeafs[i + 1]);
}
}
else
{
this.upperTreehashLeaf = upperTreehashLeaf;
}
if (minTreehash == null)
{
this.minTreehash = new int[numLayer - 1];
for (int i = 0; i < numLayer - 1; i++)
{
this.minTreehash[i] = -1;
}
}
else
{
this.minTreehash = minTreehash;
}
// construct the nextRootSig (RootSig++)
byte[] dummy = new byte[mdLength];
byte[] OTSseed = new byte[mdLength];
if (nextRootSig == null)
{
this.nextRootSig = new GMSSRootSig[numLayer - 1];
for (int i = 0; i < numLayer - 1; i++)
{
System.arraycopy(currentSeeds[i], 0, dummy, 0, mdLength);
gmssRandom.nextSeed(dummy);
OTSseed = gmssRandom.nextSeed(dummy);
this.nextRootSig[i] = new GMSSRootSig(digestProvider.get(), otsIndex[i],
heightOfTrees[i + 1]);
this.nextRootSig[i].initSign(OTSseed, nextRoot[i]);
}
}
else
{
this.nextRootSig = nextRootSig;
}
}
// we assume this only gets called from nextKey so used is never copied.
private GMSSPrivateKeyParameters(GMSSPrivateKeyParameters original)
{
super(true, original.getParameters());
this.index = Arrays.clone(original.index);
this.currentSeeds = Arrays.clone(original.currentSeeds);
this.nextNextSeeds = Arrays.clone(original.nextNextSeeds);
this.currentAuthPaths = Arrays.clone(original.currentAuthPaths);
this.nextAuthPaths = Arrays.clone(original.nextAuthPaths);
this.currentTreehash = original.currentTreehash;
this.nextTreehash = original.nextTreehash;
this.currentStack = original.currentStack;
this.nextStack = original.nextStack;
this.currentRetain = original.currentRetain;
this.nextRetain = original.nextRetain;
this.keep = Arrays.clone(original.keep);
this.nextNextLeaf = original.nextNextLeaf;
this.upperLeaf = original.upperLeaf;
this.upperTreehashLeaf = original.upperTreehashLeaf;
this.minTreehash = original.minTreehash;
this.gmssPS = original.gmssPS;
this.nextRoot = Arrays.clone(original.nextRoot);
this.nextNextRoot = original.nextNextRoot;
this.currentRootSig = original.currentRootSig;
this.nextRootSig = original.nextRootSig;
this.digestProvider = original.digestProvider;
this.heightOfTrees = original.heightOfTrees;
this.otsIndex = original.otsIndex;
this.K = original.K;
this.numLayer = original.numLayer;
this.messDigestTrees = original.messDigestTrees;
this.mdLength = original.mdLength;
this.gmssRandom = original.gmssRandom;
this.numLeafs = original.numLeafs;
}
public boolean isUsed()
{
return this.used;
}
public void markUsed()
{
this.used = true;
}
public GMSSPrivateKeyParameters nextKey()
{
GMSSPrivateKeyParameters nKey = new GMSSPrivateKeyParameters(this);
nKey.nextKey(gmssPS.getNumOfLayers() - 1);
return nKey;
}
/**
* This method updates the GMSS private key for the next signature
*
* @param layer the layer where the next key is processed
*/
private void nextKey(int layer)
{
// only for lowest layer ( other layers indices are raised in nextTree()
// method )
if (layer == numLayer - 1)
{
index[layer]++;
} // else System.out.println(" --- nextKey on layer " + layer + "
// index is now : " + index[layer]);
// if tree of this layer is depleted
if (index[layer] == numLeafs[layer])
{
if (numLayer != 1)
{
nextTree(layer);
index[layer] = 0;
}
}
else
{
updateKey(layer);
}
}
/**
* Switch to next subtree if the current one is depleted
*
* @param layer the layer where the next tree is processed
*/
private void nextTree(int layer)
{
// System.out.println("NextTree method called on layer " + layer);
// dont create next tree for the top layer
if (layer > 0)
{
// raise index for upper layer
index[layer - 1]++;
// test if it is already the last tree
boolean lastTree = true;
int z = layer;
do
{
z--;
if (index[z] < numLeafs[z])
{
lastTree = false;
}
}
while (lastTree && (z > 0));
// only construct next subtree if last one is not already in use
if (!lastTree)
{
gmssRandom.nextSeed(currentSeeds[layer]);
// last step of distributed signature calculation
nextRootSig[layer - 1].updateSign();
// last step of distributed leaf calculation for nextNextLeaf
if (layer > 1)
{
nextNextLeaf[layer - 1 - 1] = nextNextLeaf[layer - 1 - 1].nextLeaf();
}
// last step of distributed leaf calculation for upper leaf
upperLeaf[layer - 1] = upperLeaf[layer - 1].nextLeaf();
// last step of distributed leaf calculation for all treehashs
if (minTreehash[layer - 1] >= 0)
{
upperTreehashLeaf[layer - 1] = upperTreehashLeaf[layer - 1].nextLeaf();
byte[] leaf = this.upperTreehashLeaf[layer - 1].getLeaf();
// if update is required use the precomputed leaf to update
// treehash
try
{
currentTreehash[layer - 1][minTreehash[layer - 1]]
.update(this.gmssRandom, leaf);
// System.out.println("UUUpdated TH " +
// minTreehash[layer - 1]);
if (currentTreehash[layer - 1][minTreehash[layer - 1]]
.wasFinished())
{
// System.out.println("FFFinished TH " +
// minTreehash[layer - 1]);
}
}
catch (Exception e)
{
System.out.println(e);
}
}
// last step of nextNextAuthRoot calculation
this.updateNextNextAuthRoot(layer);
// ******************************************************** /
// NOW: advance to next tree on layer 'layer'
// NextRootSig --> currentRootSigs
this.currentRootSig[layer - 1] = nextRootSig[layer - 1]
.getSig();
// -----------------------
// nextTreehash --> currentTreehash
// nextNextTreehash --> nextTreehash
for (int i = 0; i < heightOfTrees[layer] - K[layer]; i++)
{
this.currentTreehash[layer][i] = this.nextTreehash[layer - 1][i];
this.nextTreehash[layer - 1][i] = this.nextNextRoot[layer - 1]
.getTreehash()[i];
}
// NextAuthPath --> currentAuthPath
// nextNextAuthPath --> nextAuthPath
for (int i = 0; i < heightOfTrees[layer]; i++)
{
System.arraycopy(nextAuthPaths[layer - 1][i], 0,
currentAuthPaths[layer][i], 0, mdLength);
System.arraycopy(nextNextRoot[layer - 1].getAuthPath()[i],
0, nextAuthPaths[layer - 1][i], 0, mdLength);
}
// nextRetain --> currentRetain
// nextNextRetain --> nextRetain
for (int i = 0; i < K[layer] - 1; i++)
{
this.currentRetain[layer][i] = this.nextRetain[layer - 1][i];
this.nextRetain[layer - 1][i] = this.nextNextRoot[layer - 1]
.getRetain()[i];
}
// nextStack --> currentStack
this.currentStack[layer] = this.nextStack[layer - 1];
// nextNextStack --> nextStack
this.nextStack[layer - 1] = this.nextNextRoot[layer - 1]
.getStack();
// nextNextRoot --> nextRoot
this.nextRoot[layer - 1] = this.nextNextRoot[layer - 1]
.getRoot();
// -----------------------
// -----------------
byte[] OTSseed = new byte[mdLength];
byte[] dummy = new byte[mdLength];
// gmssRandom.setSeed(currentSeeds[layer]);
System
.arraycopy(currentSeeds[layer - 1], 0, dummy, 0,
mdLength);
OTSseed = gmssRandom.nextSeed(dummy); // only need OTSSeed
OTSseed = gmssRandom.nextSeed(dummy);
OTSseed = gmssRandom.nextSeed(dummy);
// nextWinSig[layer-1]=new
// GMSSWinSig(OTSseed,algNames,otsIndex[layer-1],heightOfTrees[layer],nextRoot[layer-1]);
nextRootSig[layer - 1].initSign(OTSseed, nextRoot[layer - 1]);
// nextKey for upper layer
nextKey(layer - 1);
}
}
}
/**
* This method computes the authpath (AUTH) for the current tree,
* Additionally the root signature for the next tree (SIG+), the authpath
* (AUTH++) and root (ROOT++) for the tree after next in layer
* layer, and the LEAF++^1 for the next next tree in the
* layer above are updated This method is used by nextKey()
*
* @param layer
*/
private void updateKey(int layer)
{
// ----------current tree processing of actual layer---------
// compute upcoming authpath for current Tree (AUTH)
computeAuthPaths(layer);
// -----------distributed calculations part------------
// not for highest tree layer
if (layer > 0)
{
// compute (partial) next leaf on TREE++ (not on layer 1 and 0)
if (layer > 1)
{
nextNextLeaf[layer - 1 - 1] = nextNextLeaf[layer - 1 - 1].nextLeaf();
}
// compute (partial) next leaf on tree above (not on layer 0)
upperLeaf[layer - 1] = upperLeaf[layer - 1].nextLeaf();
// compute (partial) next leaf for all treehashs on tree above (not
// on layer 0)
int t = (int)Math
.floor((double)(this.getNumLeafs(layer) * 2)
/ (double)(this.heightOfTrees[layer - 1] - this.K[layer - 1]));
if (index[layer] % t == 1)
{
// System.out.println(" layer: " + layer + " index: " +
// index[layer] + " t : " + t);
// take precomputed node for treehash update
// ------------------------------------------------
if (index[layer] > 1 && minTreehash[layer - 1] >= 0)
{
byte[] leaf = this.upperTreehashLeaf[layer - 1].getLeaf();
// if update is required use the precomputed leaf to update
// treehash
try
{
currentTreehash[layer - 1][minTreehash[layer - 1]]
.update(this.gmssRandom, leaf);
// System.out.println("Updated TH " + minTreehash[layer
// - 1]);
if (currentTreehash[layer - 1][minTreehash[layer - 1]]
.wasFinished())
{
// System.out.println("Finished TH " +
// minTreehash[layer - 1]);
}
}
catch (Exception e)
{
System.out.println(e);
}
// ------------------------------------------------
}
// initialize next leaf precomputation
// ------------------------------------------------
// get lowest index of treehashs
this.minTreehash[layer - 1] = getMinTreehashIndex(layer - 1);
if (this.minTreehash[layer - 1] >= 0)
{
// initialize leaf
byte[] seed = this.currentTreehash[layer - 1][this.minTreehash[layer - 1]]
.getSeedActive();
this.upperTreehashLeaf[layer - 1] = new GMSSLeaf(
this.digestProvider.get(), this.otsIndex[layer - 1], t, seed);
this.upperTreehashLeaf[layer - 1] = this.upperTreehashLeaf[layer - 1].nextLeaf();
// System.out.println("restarted treehashleaf (" + (layer -
// 1) + "," + this.minTreehash[layer - 1] + ")");
}
// ------------------------------------------------
}
else
{
// update the upper leaf for the treehash one step
if (this.minTreehash[layer - 1] >= 0)
{
this.upperTreehashLeaf[layer - 1] = this.upperTreehashLeaf[layer - 1].nextLeaf();
// if (minTreehash[layer - 1] > 3)
// System.out.print("#");
}
}
// compute (partial) the signature of ROOT+ (RootSig+) (not on top
// layer)
nextRootSig[layer - 1].updateSign();
// compute (partial) AUTHPATH++ & ROOT++ (not on top layer)
if (index[layer] == 1)
{
// init root and authpath calculation for tree after next
// (AUTH++, ROOT++)
this.nextNextRoot[layer - 1].initialize(new Vector());
}
// update root and authpath calculation for tree after next (AUTH++,
// ROOT++)
this.updateNextNextAuthRoot(layer);
}
// ----------- end distributed calculations part-----------------
}
/**
* This method returns the index of the next Treehash instance that should
* receive an update
*
* @param layer the layer of the GMSS tree
* @return index of the treehash instance that should get the update
*/
private int getMinTreehashIndex(int layer)
{
int minTreehash = -1;
for (int h = 0; h < heightOfTrees[layer] - K[layer]; h++)
{
if (currentTreehash[layer][h].wasInitialized()
&& !currentTreehash[layer][h].wasFinished())
{
if (minTreehash == -1)
{
minTreehash = h;
}
else if (currentTreehash[layer][h].getLowestNodeHeight() < currentTreehash[layer][minTreehash]
.getLowestNodeHeight())
{
minTreehash = h;
}
}
}
return minTreehash;
}
/**
* Computes the upcoming currentAuthpath of layer layer using
* the revisited authentication path computation of Dahmen/Schneider 2008
*
* @param layer the actual layer
*/
private void computeAuthPaths(int layer)
{
int Phi = index[layer];
int H = heightOfTrees[layer];
int K = this.K[layer];
// update all nextSeeds for seed scheduling
for (int i = 0; i < H - K; i++)
{
currentTreehash[layer][i].updateNextSeed(gmssRandom);
}
// STEP 1 of Algorithm
int Tau = heightOfPhi(Phi);
byte[] OTSseed = new byte[mdLength];
OTSseed = gmssRandom.nextSeed(currentSeeds[layer]);
// STEP 2 of Algorithm
// if phi's parent on height tau + 1 if left node, store auth_tau
// in keep_tau.
// TODO check it, formerly was
// int L = Phi / (int) Math.floor(Math.pow(2, Tau + 1));
// L %= 2;
int L = (Phi >>> (Tau + 1)) & 1;
byte[] tempKeep = new byte[mdLength];
// store the keep node not in keep[layer][tau/2] because it might be in
// use
// wait until the space is freed in step 4a
if (Tau < H - 1 && L == 0)
{
System.arraycopy(currentAuthPaths[layer][Tau], 0, tempKeep, 0,
mdLength);
}
byte[] help = new byte[mdLength];
// STEP 3 of Algorithm
// if phi is left child, compute and store leaf for next currentAuthPath
// path,
// (obtained by veriying current signature)
if (Tau == 0)
{
// LEAFCALC !!!
if (layer == numLayer - 1)
{ // lowest layer computes the
// necessary leaf completely at this
// time
WinternitzOTSignature ots = new WinternitzOTSignature(OTSseed,
digestProvider.get(), otsIndex[layer]);
help = ots.getPublicKey();
}
else
{ // other layers use the precomputed leafs in
// nextNextLeaf
byte[] dummy = new byte[mdLength];
System.arraycopy(currentSeeds[layer], 0, dummy, 0, mdLength);
gmssRandom.nextSeed(dummy);
help = upperLeaf[layer].getLeaf();
this.upperLeaf[layer].initLeafCalc(dummy);
// WinternitzOTSVerify otsver = new
// WinternitzOTSVerify(algNames, otsIndex[layer]);
// byte[] help2 = otsver.Verify(currentRoot[layer],
// currentRootSig[layer]);
// System.out.println(" --- " + layer + " " +
// ByteUtils.toHexString(help) + " " +
// ByteUtils.toHexString(help2));
}
System.arraycopy(help, 0, currentAuthPaths[layer][0], 0, mdLength);
}
else
{
// STEP 4a of Algorithm
// get new left currentAuthPath node on height tau
byte[] toBeHashed = new byte[mdLength << 1];
System.arraycopy(currentAuthPaths[layer][Tau - 1], 0, toBeHashed,
0, mdLength);
// free the shared keep[layer][tau/2]
System.arraycopy(keep[layer][(int)Math.floor((Tau - 1) / 2)], 0,
toBeHashed, mdLength, mdLength);
messDigestTrees.update(toBeHashed, 0, toBeHashed.length);
currentAuthPaths[layer][Tau] = new byte[messDigestTrees.getDigestSize()];
messDigestTrees.doFinal(currentAuthPaths[layer][Tau], 0);
// STEP 4b and 4c of Algorithm
// copy right nodes to currentAuthPath on height 0..Tau-1
for (int i = 0; i < Tau; i++)
{
// STEP 4b of Algorithm
// 1st: copy from treehashs
if (i < H - K)
{
if (currentTreehash[layer][i].wasFinished())
{
System.arraycopy(currentTreehash[layer][i]
.getFirstNode(), 0, currentAuthPaths[layer][i],
0, mdLength);
currentTreehash[layer][i].destroy();
}
else
{
System.err
.println("Treehash ("
+ layer
+ ","
+ i
+ ") not finished when needed in AuthPathComputation");
}
}
// 2nd: copy precomputed values from Retain
if (i < H - 1 && i >= H - K)
{
if (currentRetain[layer][i - (H - K)].size() > 0)
{
// pop element from retain
System.arraycopy(currentRetain[layer][i - (H - K)]
.lastElement(), 0, currentAuthPaths[layer][i],
0, mdLength);
currentRetain[layer][i - (H - K)]
.removeElementAt(currentRetain[layer][i
- (H - K)].size() - 1);
}
}
// STEP 4c of Algorithm
// initialize new stack at heights 0..Tau-1
if (i < H - K)
{
// create stacks anew
int startPoint = Phi + 3 * (1 << i);
if (startPoint < numLeafs[layer])
{
// if (layer < 2) {
// System.out.println("initialized TH " + i + " on layer
// " + layer);
// }
currentTreehash[layer][i].initialize();
}
}
}
}
// now keep space is free to use
if (Tau < H - 1 && L == 0)
{
System.arraycopy(tempKeep, 0,
keep[layer][(int)Math.floor(Tau / 2)], 0, mdLength);
}
// only update empty stack at height h if all other stacks have
// tailnodes with height >h
// finds active stack with lowest node height, choses lower index in
// case of tie
// on the lowest layer leafs must be computed at once, no precomputation
// is possible. So all treehash updates are done at once here
if (layer == numLayer - 1)
{
for (int tmp = 1; tmp <= (H - K) / 2; tmp++)
{
// index of the treehash instance that receives the next update
int minTreehash = getMinTreehashIndex(layer);
// if active treehash is found update with a leaf
if (minTreehash >= 0)
{
try
{
byte[] seed = new byte[mdLength];
System.arraycopy(
this.currentTreehash[layer][minTreehash]
.getSeedActive(), 0, seed, 0, mdLength);
byte[] seed2 = gmssRandom.nextSeed(seed);
WinternitzOTSignature ots = new WinternitzOTSignature(
seed2, this.digestProvider.get(), this.otsIndex[layer]);
byte[] leaf = ots.getPublicKey();
currentTreehash[layer][minTreehash].update(
this.gmssRandom, leaf);
}
catch (Exception e)
{
System.out.println(e);
}
}
}
}
else
{ // on higher layers the updates are done later
this.minTreehash[layer] = getMinTreehashIndex(layer);
}
}
/**
* Returns the largest h such that 2^h | Phi
*
* @param Phi the leaf index
* @return The largest h with 2^h | Phi if
* Phi!=0 else return -1
*/
private int heightOfPhi(int Phi)
{
if (Phi == 0)
{
return -1;
}
int Tau = 0;
int modul = 1;
while (Phi % modul == 0)
{
modul *= 2;
Tau += 1;
}
return Tau - 1;
}
/**
* Updates the authentication path and root calculation for the tree after
* next (AUTH++, ROOT++) in layer layer
*
* @param layer
*/
private void updateNextNextAuthRoot(int layer)
{
byte[] OTSseed = new byte[mdLength];
OTSseed = gmssRandom.nextSeed(nextNextSeeds[layer - 1]);
// get the necessary leaf
if (layer == numLayer - 1)
{ // lowest layer computes the necessary
// leaf completely at this time
WinternitzOTSignature ots = new WinternitzOTSignature(OTSseed,
digestProvider.get(), otsIndex[layer]);
this.nextNextRoot[layer - 1].update(nextNextSeeds[layer - 1], ots
.getPublicKey());
}
else
{ // other layers use the precomputed leafs in nextNextLeaf
this.nextNextRoot[layer - 1].update(nextNextSeeds[layer - 1], nextNextLeaf[layer - 1].getLeaf());
this.nextNextLeaf[layer - 1].initLeafCalc(nextNextSeeds[layer - 1]);
}
}
public int[] getIndex()
{
return index;
}
/**
* @return The current index of layer i
*/
public int getIndex(int i)
{
return index[i];
}
public byte[][] getCurrentSeeds()
{
return Arrays.clone(currentSeeds);
}
public byte[][][] getCurrentAuthPaths()
{
return Arrays.clone(currentAuthPaths);
}
/**
* @return The one-time signature of the root of the current subtree
*/
public byte[] getSubtreeRootSig(int i)
{
return currentRootSig[i];
}
public GMSSDigestProvider getName()
{
return digestProvider;
}
/**
* @return The number of leafs of each tree of layer i
*/
public int getNumLeafs(int i)
{
return numLeafs[i];
}
}
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