Scratch

You can set an id variable, of each one.
All that has to happen is that when a new project is connected, the client project generates the id number.
It then broadcasts to the host that it is a) connected and b) to tell it to get the value of the id (from the variable sensor, since it was the last connected).

Now, the host has a variable called something like 'sendto.'
It sets this to the id of the client which it wishes to send a broadcast to, and then sends the broadcast. All of the receiver blocks should have an if at the top that says:
<if><<  <not> <( <{ id }> <=> (sensor value (sendto) )> >>
|<stop script>
<end>[/blocks]
This way, all scripts triggered on a client with the wrong id are terminated.

Understand?

sparks wrote:

a good test of something like this is where you get someone else to try and hack it - eg, get the name or password of someone else to see how secure the information is, before setting it up, also hacking it yourself! if there's no way for YOU to do it, there probably isn't a way, seeing as you scripted it. I'm going to have a look at how some web data is encrypted and copy that.

i'm thinking if each project upon startup generates a random order in which to muddle up the characters it sends, then as long as the host has a copy of that random order to decode it at the other end, the data will be muddled up to any other viewer. the flaw with that is that the random order needs to be sent at some point, and someone can see it then and make a note.

I don't want to use substitution as it requires lots of scripting and really slows down data sending.

What your getting into know, as i see it, requires BYOB, and if you use BYOB, then you can use its compiler, to make it almost completely fool proof, so that unless the person someone how manages to de compiler the exe and get at its variables, which i dont think is possible, its safe!

sparks wrote:

I thought that the Compiler for BYOB didn't actually compile the project, just opened it in full screen.

There is no true compiler for scratch, but it does make it an .exe but you do view it in Presentation mode. Iv only used the chirp compiler before, but there shouldn't much of a difference. Except that the BYOB one works with homemade blocks.