byte[] seed = new byte[label.length + nonce.length];
System.arraycopy(label, 0, seed, 0, label.length);
System.arraycopy(nonce, 0, seed, label.length, nonce.length);
DerivationAlgorithm algo =
AlgoFactory.getInstance(ConversationConstants.DerivationAlgorithm.P_SHA_1);
derivedKeyBytes = algo.createKey(ephemeralKey, seed, offset, length);
// Add the DKTs
dkt = new DerivedKeyToken(wscVersion, document);
dktId = getWsConfig().getIdAllocator().createId("DK-", dkt);