Live Demo

metamask turn on is required (done this way for easy check, "nostyle"-style)

Steps for manual test

create public / private rsa key for chats
create lottery (and you will be the owner)
change metamask account to player and reload
buy tickets (and you will be the player)
wait till all tickets will be sold (reload with different accounts)
got winner after lottery finish (any account could fire)
send message to lottery owner from winner account (only winner or owner could chat in lottery contract)
unfreeze lottery owner money (only winner could do)
actually get lottery money (any account could fire - but will directly to owner)