org.bouncycastle.pqc.crypto.xmss.XMSSNodeUtil Maven / Gradle / Ivy
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package org.bouncycastle.pqc.crypto.xmss;
class XMSSNodeUtil
{
/**
* Compresses a WOTS+ public key to a single n-byte string.
*
* @param publicKey WOTS+ public key to compress.
* @param address Address.
* @return Compressed n-byte string of public key.
*/
static XMSSNode lTree(WOTSPlus wotsPlus, WOTSPlusPublicKeyParameters publicKey, LTreeAddress address)
{
if (publicKey == null)
{
throw new NullPointerException("publicKey == null");
}
if (address == null)
{
throw new NullPointerException("address == null");
}
int len = wotsPlus.getParams().getLen();
/* duplicate public key to XMSSNode Array */
byte[][] publicKeyBytes = publicKey.toByteArray();
XMSSNode[] publicKeyNodes = new XMSSNode[publicKeyBytes.length];
for (int i = 0; i < publicKeyBytes.length; i++)
{
publicKeyNodes[i] = new XMSSNode(0, publicKeyBytes[i]);
}
address = (LTreeAddress)new LTreeAddress.Builder().withLayerAddress(address.getLayerAddress())
.withTreeAddress(address.getTreeAddress()).withLTreeAddress(address.getLTreeAddress()).withTreeHeight(0)
.withTreeIndex(address.getTreeIndex()).withKeyAndMask(address.getKeyAndMask()).build();
while (len > 1)
{
for (int i = 0; i < (int)Math.floor(len / 2); i++)
{
address = (LTreeAddress)new LTreeAddress.Builder().withLayerAddress(address.getLayerAddress())
.withTreeAddress(address.getTreeAddress()).withLTreeAddress(address.getLTreeAddress())
.withTreeHeight(address.getTreeHeight()).withTreeIndex(i)
.withKeyAndMask(address.getKeyAndMask()).build();
publicKeyNodes[i] = randomizeHash(wotsPlus, publicKeyNodes[2 * i], publicKeyNodes[(2 * i) + 1], address);
}
if (len % 2 == 1)
{
publicKeyNodes[(int)Math.floor(len / 2)] = publicKeyNodes[len - 1];
}
len = (int)Math.ceil((double)len / 2);
address = (LTreeAddress)new LTreeAddress.Builder().withLayerAddress(address.getLayerAddress())
.withTreeAddress(address.getTreeAddress()).withLTreeAddress(address.getLTreeAddress())
.withTreeHeight(address.getTreeHeight() + 1).withTreeIndex(address.getTreeIndex())
.withKeyAndMask(address.getKeyAndMask()).build();
}
return publicKeyNodes[0];
}
/**
* Randomization of nodes in binary tree.
*
* @param left Left node.
* @param right Right node.
* @param address Address.
* @return Randomized hash of parent of left / right node.
*/
static XMSSNode randomizeHash(WOTSPlus wotsPlus, XMSSNode left, XMSSNode right, XMSSAddress address)
{
if (left == null)
{
throw new NullPointerException("left == null");
}
if (right == null)
{
throw new NullPointerException("right == null");
}
if (left.getHeight() != right.getHeight())
{
throw new IllegalStateException("height of both nodes must be equal");
}
if (address == null)
{
throw new NullPointerException("address == null");
}
byte[] publicSeed = wotsPlus.getPublicSeed();
if (address instanceof LTreeAddress)
{
LTreeAddress tmpAddress = (LTreeAddress)address;
address = (LTreeAddress)new LTreeAddress.Builder().withLayerAddress(tmpAddress.getLayerAddress())
.withTreeAddress(tmpAddress.getTreeAddress()).withLTreeAddress(tmpAddress.getLTreeAddress())
.withTreeHeight(tmpAddress.getTreeHeight()).withTreeIndex(tmpAddress.getTreeIndex())
.withKeyAndMask(0).build();
}
else if (address instanceof HashTreeAddress)
{
HashTreeAddress tmpAddress = (HashTreeAddress)address;
address = (HashTreeAddress)new HashTreeAddress.Builder().withLayerAddress(tmpAddress.getLayerAddress())
.withTreeAddress(tmpAddress.getTreeAddress()).withTreeHeight(tmpAddress.getTreeHeight())
.withTreeIndex(tmpAddress.getTreeIndex()).withKeyAndMask(0).build();
}
byte[] key = wotsPlus.getKhf().PRF(publicSeed, address.toByteArray());
if (address instanceof LTreeAddress)
{
LTreeAddress tmpAddress = (LTreeAddress)address;
address = (LTreeAddress)new LTreeAddress.Builder().withLayerAddress(tmpAddress.getLayerAddress())
.withTreeAddress(tmpAddress.getTreeAddress()).withLTreeAddress(tmpAddress.getLTreeAddress())
.withTreeHeight(tmpAddress.getTreeHeight()).withTreeIndex(tmpAddress.getTreeIndex())
.withKeyAndMask(1).build();
}
else if (address instanceof HashTreeAddress)
{
HashTreeAddress tmpAddress = (HashTreeAddress)address;
address = (HashTreeAddress)new HashTreeAddress.Builder().withLayerAddress(tmpAddress.getLayerAddress())
.withTreeAddress(tmpAddress.getTreeAddress()).withTreeHeight(tmpAddress.getTreeHeight())
.withTreeIndex(tmpAddress.getTreeIndex()).withKeyAndMask(1).build();
}
byte[] bitmask0 = wotsPlus.getKhf().PRF(publicSeed, address.toByteArray());
if (address instanceof LTreeAddress)
{
LTreeAddress tmpAddress = (LTreeAddress)address;
address = (LTreeAddress)new LTreeAddress.Builder().withLayerAddress(tmpAddress.getLayerAddress())
.withTreeAddress(tmpAddress.getTreeAddress()).withLTreeAddress(tmpAddress.getLTreeAddress())
.withTreeHeight(tmpAddress.getTreeHeight()).withTreeIndex(tmpAddress.getTreeIndex())
.withKeyAndMask(2).build();
}
else if (address instanceof HashTreeAddress)
{
HashTreeAddress tmpAddress = (HashTreeAddress)address;
address = (HashTreeAddress)new HashTreeAddress.Builder().withLayerAddress(tmpAddress.getLayerAddress())
.withTreeAddress(tmpAddress.getTreeAddress()).withTreeHeight(tmpAddress.getTreeHeight())
.withTreeIndex(tmpAddress.getTreeIndex()).withKeyAndMask(2).build();
}
byte[] bitmask1 = wotsPlus.getKhf().PRF(publicSeed, address.toByteArray());
int n = wotsPlus.getParams().getTreeDigestSize();
byte[] tmpMask = new byte[2 * n];
for (int i = 0; i < n; i++)
{
tmpMask[i] = (byte)(left.getValue()[i] ^ bitmask0[i]);
}
for (int i = 0; i < n; i++)
{
tmpMask[i + n] = (byte)(right.getValue()[i] ^ bitmask1[i]);
}
byte[] out = wotsPlus.getKhf().H(key, tmpMask);
return new XMSSNode(left.getHeight(), out);
}
}