Summary

Interested in setting up your own cold storage system on an old smartphone? Look no further than Bither, who has put together the industry’s best mobile app cold storage/hot wallet solution. This ingenious little app accomplishes this without overly complicating user interface and overall simplicity of their solution. The developers are dedicated to improving the product, as can be seen by the number of new features that have been integrated since launch in 2014, and their responsiveness to the suggestions of users on their bitcointalk thread.

Bither rolled back a really smart little 2-of-3 multisig feature because they were unsatisfied with the user experience. We spoke with the developers of Bither, and they seemed keen to release an updated multisig solution in future releases.

Getting Started

Upon first opening the app you’ll see a lovely “blackboard” design with bitcoin-related chalk drawings and a big plus sign at the bottom with an “Add” message next to it. Clicking that will prompt you to generate a new HD account using Bither’s Xrandom feature, which gathers data from the phone, camera, microphone, etc to put together a truly random master seed. Click ok, enter your password, and start shake, shake shaking your phone! After a moment you’ll be presented with a 12 word passphrase, the mnemonic for the HD seed, which should be written in a safe location. If you’d like to have this seed expressed as a QR code, which can be printed, that option is also available.

OK, you have just set up your bither hot wallet.

Setting up the cold wallet

Now, the bither cold wallet is meant to be set up on an old, now unused phone that will never be connected to the internet. You’ll notice that the first time you open your bither app you won’t have the option to set up bither cold – you need to install the app on your backup and then turn on your airplane mode prior to opening.

Once you are offline, open the bither app and you’ll be asked if you would like to switch to bither cold. After switching, you go through the exact same process as explained in opening the hot wallet, above. The Xrandom feature will generate a new private key – but this will be done on your own private, entirely offline cold wallet!

Connecting the cold and hot wallets

Next step is to navigate to settings, which is located behind the gear icon in the upper right hand corner. The first option, Monitor Bither Cold, will open a camera meant to scan the bither cold wallet code. Open up “watch only QR code” on the cold wallet, and scan it. This will open up the associated cold wallets in watch-only mode in your hot wallet, so you can monitor the accounts without having to play around with the cold wallet. Additionally, you’ll be able to access the cold wallet’s public key QR code from the hot wallet, so it is just as easy to receive transactions to the cold wallet address, should you so choose.

Sending bitcoin from the cold wallet

You will be able to access and send funds from the cold wallet whilst maintaining a complete air gap between the cold wallet and the internet. We lay out the steps below.

1. Scan the recipient address with your cold wallet address from your hot wallet QR code reader. set the number of bitcoin you would like to send. This will create an unsigned transaction QR code and a tab stating “scan bither cold transaction”.
2. In the cold wallet, you’ll find a “sign transaction” prompt in the settings tab. Clicking this will open a camera interface. Scan the unsigned transaction on your hot wallet phone.
3. This will open up the transaction on your cold wallet. Enter your password and click “sign the transaction.
4. This will generate a QR code with the signed transaction. Go back to your hot wallet, click the “scan bither cold transaction” and scan the QR code. You’ve just sent bitcoin from your cold wallet without compromising security!

The Bither Wallet

The user interface is a bit different than some of the other mobile wallets and might take a bit of getting used to. Each wallet address is displayed on the homescreen as a series of boxes. A click on the address box will open a more detailed display, which includes the associated transactions, the balance, the QR code for incoming transaction, and a send box which switches you to an outbound display.

A click on the QR code opens it up for scanning, and offers the additional choice of copying the QR code as a picture or sending it to an email or SMS recipient.

A click on the send box opens a pay to field, along with amount of bitcoin, input in either bitcoin or your selected currency equivalent, as well as a camera box to scan address. After all fields are filled, submit your password and send. Please note that the default currency, as well as the default exchange for determining conversion rate, can both be set from the settings tab.

Speaking of the setting tab, I’ve stuck below screenshots showing all the different capabilities of the wallet. A click on the “advanced options” allows setting your pin number, which should be done for convenience. If your mobile device comes equipped with touchID, this will be automatically enabled on each login; otherwise, the pin greatly expediates the process. Most options are relatively self explanatory; you’ll notice an “HDM Recovery” tab – this tab was meant for the multisig solution, which has been temporarily rolled back. If the Bither server was down, the HDM recovery would allow for sorting out the two-of-three signing using the hot and cold wallets.

Additional bits and bobs

You’ll notice a chart icon in the upper left hand corner – this displays the bitcoin price across 10 of the most popular exchanges in the market. On the cold wallet side, the same icon location shows a “safety gauge” of your private keys. Was something done to compromise the cold wallet – for instance, if it was connected to the internet mistakenly – the security will show up as less than 100%.  A click on the bitcoin emblem at the top of the screen will take you back to the homescreen, while a double click will open a fancy little circle chart showing the allocation of your holding between different addresses.

Conclusion

Thanks to a dedicated group of developers, Bither continues to improve on a product that has already brought a few interesting innovations to the market, namely their mobile cold wallet solution. While some of the conveniences available on simpler apps – such as address books for instance – are missing from Bither, this is more than compensated by their advanced features.