Suggestion for cold storage and offline signing

[Dende]

Hi,

I would like to suggest cold storage solution within Bitcoin Wallet like the one employed within electrum and armory.
Meaning one phone is connected to the internet to transmit transactions and another phone as cold storage and for signing transactions.
Transactions can be easily transferred between both devices by using qr code or bluetooth which is more convenient than pc cold storage solution and more portable as well.

I have an old phone that I want to use as cold storage and do offline signing but there seems to be no solution for this yet.
I believe many others like me have an old phone that is just collecting dust so I think addition of this feature would be great.
People can give a new purpose to their old phones as hardware wallets.

I hope you guys would look into this. Thanks.

[Andreas Schildbach]

Direct payments via QR code, NFC or the payment protocol (Bluetooth or HTTPS) are implemented already. So you could start experimenting with that usecase today.

One problem is that with the app, you can't spend unconfirmed coins. That means you somehow need to get proof of confirmation (e.g. blockchain headers) to the cold storage device. Alternatively disable that check, but in this case you should not accept payments to your cold storage directly without checking on another device.

Anyway, it involves development effort. I'm currently busy with other stuff. Maybe a project for the upcoming Berlin-Texas hackathon this weekend?

[Dende]

I will look into your suggestions. Thanks.

Todays smartphones are powerful, flexible, and affordable. There is no need for a dedicated hardware cold wallet as a smartphone can be turned into one.
Eventhough I myself have a Trezor underway but I see cold wallet solution for smartphones would benefit a lot of people.
I hope devs involve with bitcoin would look into this.

I will send an email to the organizer of the hackathon, maybe they can spread this idea around.