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package org.spongycastle.crypto.tls;
import java.util.Enumeration;
import java.util.Hashtable;
import org.spongycastle.crypto.Digest;
import org.spongycastle.util.Shorts;
/**
* Buffers input until the hash algorithm is determined.
*/
class DeferredHash
implements TlsHandshakeHash
{
protected static final int BUFFERING_HASH_LIMIT = 4;
protected TlsContext context;
private DigestInputBuffer buf;
private Hashtable hashes;
private Short prfHashAlgorithm;
DeferredHash()
{
this.buf = new DigestInputBuffer();
this.hashes = new Hashtable();
this.prfHashAlgorithm = null;
}
private DeferredHash(Short prfHashAlgorithm, Digest prfHash)
{
this.buf = null;
this.hashes = new Hashtable();
this.prfHashAlgorithm = prfHashAlgorithm;
hashes.put(prfHashAlgorithm, prfHash);
}
public void init(TlsContext context)
{
this.context = context;
}
public TlsHandshakeHash notifyPRFDetermined()
{
int prfAlgorithm = context.getSecurityParameters().getPrfAlgorithm();
if (prfAlgorithm == PRFAlgorithm.tls_prf_legacy)
{
CombinedHash legacyHash = new CombinedHash();
legacyHash.init(context);
buf.updateDigest(legacyHash);
return legacyHash.notifyPRFDetermined();
}
this.prfHashAlgorithm = Shorts.valueOf(TlsUtils.getHashAlgorithmForPRFAlgorithm(prfAlgorithm));
checkTrackingHash(prfHashAlgorithm);
return this;
}
public void trackHashAlgorithm(short hashAlgorithm)
{
if (buf == null)
{
throw new IllegalStateException("Too late to track more hash algorithms");
}
checkTrackingHash(Shorts.valueOf(hashAlgorithm));
}
public void sealHashAlgorithms()
{
checkStopBuffering();
}
public TlsHandshakeHash stopTracking()
{
Digest prfHash = TlsUtils.cloneHash(prfHashAlgorithm.shortValue(), (Digest)hashes.get(prfHashAlgorithm));
if (buf != null)
{
buf.updateDigest(prfHash);
}
DeferredHash result = new DeferredHash(prfHashAlgorithm, prfHash);
result.init(context);
return result;
}
public Digest forkPRFHash()
{
checkStopBuffering();
if (buf != null)
{
Digest prfHash = TlsUtils.createHash(prfHashAlgorithm.shortValue());
buf.updateDigest(prfHash);
return prfHash;
}
return TlsUtils.cloneHash(prfHashAlgorithm.shortValue(), (Digest)hashes.get(prfHashAlgorithm));
}
public byte[] getFinalHash(short hashAlgorithm)
{
Digest d = (Digest)hashes.get(Shorts.valueOf(hashAlgorithm));
if (d == null)
{
throw new IllegalStateException("HashAlgorithm " + hashAlgorithm + " is not being tracked");
}
d = TlsUtils.cloneHash(hashAlgorithm, d);
if (buf != null)
{
buf.updateDigest(d);
}
byte[] bs = new byte[d.getDigestSize()];
d.doFinal(bs, 0);
return bs;
}
public String getAlgorithmName()
{
throw new IllegalStateException("Use fork() to get a definite Digest");
}
public int getDigestSize()
{
throw new IllegalStateException("Use fork() to get a definite Digest");
}
public void update(byte input)
{
if (buf != null)
{
buf.write(input);
return;
}
Enumeration e = hashes.elements();
while (e.hasMoreElements())
{
Digest hash = (Digest)e.nextElement();
hash.update(input);
}
}
public void update(byte[] input, int inOff, int len)
{
if (buf != null)
{
buf.write(input, inOff, len);
return;
}
Enumeration e = hashes.elements();
while (e.hasMoreElements())
{
Digest hash = (Digest)e.nextElement();
hash.update(input, inOff, len);
}
}
public int doFinal(byte[] output, int outOff)
{
throw new IllegalStateException("Use fork() to get a definite Digest");
}
public void reset()
{
if (buf != null)
{
buf.reset();
return;
}
Enumeration e = hashes.elements();
while (e.hasMoreElements())
{
Digest hash = (Digest)e.nextElement();
hash.reset();
}
}
protected void checkStopBuffering()
{
if (buf != null && hashes.size() <= BUFFERING_HASH_LIMIT)
{
Enumeration e = hashes.elements();
while (e.hasMoreElements())
{
Digest hash = (Digest)e.nextElement();
buf.updateDigest(hash);
}
this.buf = null;
}
}
protected void checkTrackingHash(Short hashAlgorithm)
{
if (!hashes.containsKey(hashAlgorithm))
{
Digest hash = TlsUtils.createHash(hashAlgorithm.shortValue());
hashes.put(hashAlgorithm, hash);
}
}
}
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