/// <inheritdoc />
public MaskedAuthenticatedMessage Create(
MerkleTree tree,
int index,
TryteString message,
Hash nextRoot,
TryteString channelKey,
Entity.Mode mode,
int securityLevel)
{
var nextRootTrits = nextRoot.ToTrits();
var messageTrits = message.ToTrits();
var indexTrits = Pascal.Encode(index);
var messageLengthTrits = Pascal.Encode(messageTrits.Length);
var subtree = tree.GetSubtreeByIndex(index);
this.Curl.Reset();
this.Curl.Absorb(channelKey.ToTrits());
this.Curl.Absorb(tree.Root.Hash.ToTrits());
var payload = new List <int>();
payload.InsertRange(0, indexTrits);
payload.InsertRange(indexTrits.Length, messageLengthTrits);
var nextRootStart = indexTrits.Length + messageLengthTrits.Length;
this.Curl.Absorb(payload.Take(nextRootStart).ToArray());
// encrypt next root together with message trits
payload.InsertRange(nextRootStart, this.Mask.Mask(nextRootTrits.Concat(messageTrits).ToArray(), this.Curl));
// calculate message end and add nonce
var messageEnd = nextRootStart + nextRootTrits.Length + messageTrits.Length;
this.AddNonce(securityLevel, messageEnd, payload);
// create signature, encrypt signature + sibling count (get trits from pascal) + siblings
var signature = this.SigningHelper.Signature(this.Curl.Rate(Constants.TritHashLength), subtree.Key.ToTrits());
var subtreeTrits = subtree.ToTryteString().ToTrits();
var siblingsCount = subtreeTrits.Length / Constants.TritHashLength;
var encryptedSignature = this.Mask.Mask(signature.Concat(Pascal.Encode(siblingsCount)).Concat(subtreeTrits).ToArray(), this.Curl);
// insert signature and pad to correct length (% 3 == 0)
payload.InsertRange(messageEnd + NonceLength, encryptedSignature);
PadPayload(payload);
this.Curl.Reset();
var messageAddress = this.GetMessageAddress(tree.Root.Hash, mode);
return(new MaskedAuthenticatedMessage
{
Payload = CreateBundleFromPayload(messageAddress, payload),
Root = tree.Root.Hash,
Address = messageAddress,
NextRoot = nextRoot
});
}
/// <summary>
/// The get message address.
/// </summary>
/// <param name="rootHash">
/// The root Hash.
/// </param>
/// <param name="mode">
/// The mode.
/// </param>
/// <returns>
/// The <see cref="Address"/>.
/// </returns>
private Address GetMessageAddress(TryteString rootHash, Entity.Mode mode)
{
if (mode == Entity.Mode.Public)
{
return(new Address(rootHash.Value));
}
var addressHash = this.Mask.Hash(rootHash);
return(new Address(addressHash.Value));
}
