Bitcoin Forum

Still a work in progress but feedback gratefully appreciated.

https://github.com/ianpurton/StampAndroid

So basically Stamp is mobile app HD wallet generated from a seed (currently electrum) that can then create master public keys and sign TX's. (Stamp never holds coins).

To do this it simply scans a QR code. For the user, this is very simple to use.

Example...

Online market place using multi sig for escrow.

1. On signup the market place can ask for a MPK (Master public key) via a QR code.
2. Stamp POST's back the MPK via HTTP.
3. Site can then generate any number of P2SH addresses.
4. To sign a Transaction site generates a QR code.
5. Stamp scans the code, grabs the TX using HTTP get, signs it, POST's it back.

Another Example

Online wallet

1. On signup wallets requests MPK via QR Code.
2. Stamp sends it one.
3. Wallet creates Bitcoin P2SH addresses.
4. When user wants to send a payment they have to scan the QR code to sign it.

Poor mans Trezor.

If anyone would like to help me out with this or provide (constructive) criticism, fire away.

Do you have a demo somewhere to take a look at?

I'm working on having a demonstration video soon.

Demonstration of connecting the android app to an online wallet here

http://youtu.be/TSHYu0fCEAg

1. The wallet requests a master public key from the andoid app, after that a 2 of 2 wallet can be created.
2. User creates a payment and signs it in the online wallet (by using his passphrase)
3. Transaction is created, waiting for user to sign (for the second time) with the android app.
4. User signs with android app.

This looks great! Multisig transactions are annoying to carry out repetitively, and certainly for first timers.. This app would really simplify things, and make two factor authentication for wallet providers really easy. Also love that it uses HD wallets, I'm amazed there haven't been apps offering this yet!