How safe is
https://counterwallet.io?Can somebody explain to me how is this working? How can we be sure that somebody is not putting a backdoor like form to steal our 12 words password upon login?
It's open-source, and everything is handled using javascript (on your computer). The actual login and transaction signing process isn't done on any server (in fact your passphrase is never sent to counterwallet.io), instead it all happens inside your browser:
https://counterwallet.io/js/counterwallet-min.js?v=03f7c112aa43 If you are still worried, you could run Counterwallet, or counterpartyd (the command line client) on your own computer. CounterpartyGUI (graphical user interface for your local computer) is coming soon, see
http://counterparty.io/news/counterparty-development-update-10/.
Does that mean that I can download the counterwallet.io and make a clone of it, and run it on localhost webserver?
but I can't trust it 24/7. You can never know if somebody's gonna be able at some point to inject some code into the javascript.