LoginServer HTTP-Interface ActionsPage /addToGroup
	
	select: on Login Server registered groups with short description
	
	if user is already in a group:
		// check if birth hash and user public key haven't changed
		call to node server registered with login-server containing current group of user:
		{"jsonrpc": "2.0", "method": "checkBirthHash", "params": {
		   "groupAlias":<from db group[user.group_id]>, 
		   "birthHash": <from db user.birth_hash>, 
		   "pubkey":<from db user.pubkey>, 
		   "apiKey": <unique per Login Server>
		}, "id": rand()}
		
Node Server
  search for birthHash in StateUserChangeGroup transactions in group[groupAlias]
  if found as last StateUserChangeGroup with birthHash and pubkey are correct:
	return {"jsonrpc": "2.0", "result": {"state": "success"}, "id": <id from call>}
  if not found: 
    check if a StateUserChangeGroup transaction for pubkey can be found
	if found: 
		return {"jsonrpc": "2.0", "result": {"state": "not same", "msg": "birth hash is different", "details": {"birthHash": <found birth hash>}}, "id": <id from call>}
	else:
		return {"jsonrpc": "2.0", "result": {"state": "not found", "msg": "birth hash not found"}, "id": <id from call>}
  if birth hash and pubkey from last StateUserChangeGroup not the same:
    return {"jsonrpc": "2.0", "result": {"state": "not same", "msg": "pubkey is different", "details": {"pubkey":<found pubkey>}, "id": <id from call>}

LoginServer
  cancel process if user is in group and request return not same or not found 
	show error message
  
  if user isn't already in a group:
	// check if birth hash is unique
	call all registered Nodes:
		{"jsonrpc": "2.0", "method": "checkBirthHash", "params": {
			   "groupAlias":<from db group[user.group_id]>, 
			   "birthHash": <from db user.birth_hash>, 
			   "pubkey":<from db user.pubkey>, 
			   "apiKey": <unique per Login Server>
			}, "id": rand()}

Node Server
	
	getting discovery transaction from mirror node
	searching for birth hash in global blockchain
	if found calling model.messages.gradido.DiscoverIfExist.answearUrl with:
		{
		  "birthHash": model.messages.gradido.DiscoverIfExist.value,
		  "pubkey"   : <pubkey from youngest found transaction>
		  "groupAlias": <group alias from youngest found transaction>
		  "received" : <received from youngest found transaction>
		}
  
LoginServer
	Waiting at least 2 minutes for answear(s)
		collect answears
		cancel if birthHash was discovered with another pubkey and this has the biggest received value
			show error message
		else save group alias as parent
		
	If not canceled 
		Hedera::ConsensusService::ConsensusSubmitMessage
			proto.ConsensusSubmitMessageTransactionBody.topicID = <choosen group topic id> 
			proto.ConsensusSubmitMessageTransactionBody.message = 
			model.messages.gradido.Transaction
					id = <left empty>;
					received = <left empty>;
					sigMap = model.messages.gradido.SignatureMap
						if user is group founder:
							sigPair = 
								model.messages.gradido.SignaturePair
									pubKey = <public root key of user and group founder>
									signature = ed25519 = <bodyBytes signed with user and group founder private key>
						else 
							sigPair = [
								model.messages.gradido.SignaturePair
									pubKey = <public root key of user>
									signature = ed25519 = <bodyBytes signed with user private key>
							  for i = 0, i < n, i++ 
								model.messages.gradido.SignaturePair
									pubKey = <public root key of group member>
									signature = ed25519 = <bodyBytes signed with group member private key>,
								
							], 
							
					txHash = <left empty>;
					
					bodyBytes = model.messages.gradido.TransactionBody  serialized
						memo = <empty>
						created = model.messages.gradido.TimestampSeconds
							seconds = <current timestamp>
						data = model.messages.gradido.StateCreateGroup
							name = <group name>
							alias = <group alias>
							parentGroupAlias = <parent group alias or empty>
							hederaTopicId = <from hedera answear>
			serialized	
Node Server(s)
	receiving message, validate, put into blockchain of group