package org.bouncycastle.pqc.crypto.xmss;
import org.bouncycastle.crypto.Digest;
/**
* WOTS+ Parameters.
*/
public final class WOTSPlusParameters {
/**
* OID.
*/
private final XMSSOid oid;
/**
* Digest used in WOTS+.
*/
private final Digest digest;
/**
* The message digest size.
*/
private final int digestSize;
/**
* The Winternitz parameter (currently fixed to 16).
*/
private final int winternitzParameter;
/**
* The number of n-byte string elements in a WOTS+ secret key, public key,
* and signature.
*/
private final int len;
/**
* len1.
*/
private final int len1;
/**
* len2.
*/
private final int len2;
/**
* Constructor...
*
* @param digest
* The digest used for WOTS+.
*/
protected WOTSPlusParameters(Digest digest) {
super();
if (digest == null) {
throw new NullPointerException("digest == null");
}
this.digest = digest;
digestSize = XMSSUtil.getDigestSize(digest);
winternitzParameter = 16;
len1 = (int) Math.ceil((double) (8 * digestSize) / XMSSUtil.log2(winternitzParameter));
len2 = (int) Math.floor(XMSSUtil.log2(len1 * (winternitzParameter - 1)) / XMSSUtil.log2(winternitzParameter))
+ 1;
len = len1 + len2;
oid = WOTSPlusOid.lookup(digest.getAlgorithmName(), digestSize, winternitzParameter, len);
if (oid == null) {
throw new IllegalArgumentException("cannot find OID for digest algorithm: " + digest.getAlgorithmName());
}
}
/**
* Getter OID.
*
* @return WOTS+ OID.
*/
protected XMSSOid getOid() {
return oid;
}
/**
* Getter digest.
*
* @return digest.
*/
protected Digest getDigest() {
return digest;
}
/**
* Getter digestSize.
*
* @return digestSize.
*/
protected int getDigestSize() {
return digestSize;
}
/**
* Getter WinternitzParameter.
*
* @return winternitzParameter.
*/
protected int getWinternitzParameter() {
return winternitzParameter;
}
/**
* Getter len.
*
* @return len.
*/
protected int getLen() {
return len;
}
/**
* Getter len1.
*
* @return len1.
*/
protected int getLen1() {
return len1;
}
/**
* Getter len2.
*
* @return len2.
*/
protected int getLen2() {
return len2;
}
}