Intro

Secalot RemoteScreen is an iOS and Android application that allows to view contents of Bitcoin and Ethereum transactions that are being signed by Secalot.

Secalot RemoteScreen establishes a TLS secure channel directly with a Secalot device to read out the data so that the readout transaction contents cannot be forged by anyone.

Technically, the whole system looks like this:

  • A mobile phone running Secalot RemoteScreen has to be connected to the same local WiFi network as a computer with an attached Secalot.
  • Secalot RemoteScreen establishes a connection Secalot Control Panel running on the same computer.
  • Secalot Control Panel forwards the commands it receives from Secalot RemoteScreen to the device and forwards the replies back, acting as a proxy.
  • Being able to reach the Secalot device, Secalot RemoteScreen establishes a TSL channel with it, with Secalot device acting as a TLS server and securely reads out details of a transaction that is currently being signed on that device.

 

Setting things up

Firstly, download the Secalot Remote Screen App either from Apple App Store or Google Play depending on your platform.

Connect your phone to the same WiFi network as your computer.

Start the Secalot Control Panel on your computer and connect Secalot to a USB port.

Note
Secalot Control Panel has to be of version 1.3 or higher. Please refer to this article on how to install the Secalot control panel for your operating system.
Note
Secalot device should run firmware version 3 or higher. Please refer to this article on how to update Secalot firmware.

Navigate to the “RemoteScreen” tab. Press the “Bind mobile phone” button. A QR code will be displayed.

Start Secalot Remote Screen on your mobile phone. A welcome screen would be displayed. Press the “Bind Secalot Control Panel” at the bottom of the screen.

If asked for, approve the app using the mobile phone camera, and scan the QR code displayed on the computer.
Press the “Finish” button on the Secalot Control Panel.

Before pressing the “OK” button on the mobile phone, please compare the device fingerprint displayed on the mobile phone and in the Secalot Control Panel. They should match. Dismiss the popup, pressing the “OK” button.

The mobile phone app is now bound to your Secalot device and a Control Panel instance.

Note
You can, of course, freely open and close both the Control Panel and the RemoteScreen app. Their bounding state will not change.

The main Secalot RemoteScreen page is now opened. On the top of the screen, you can see a status line displaying if the app can find a running copy of Secalot Control Panel it was bound with.
If the status line is green, everything works as expected. If it is yellow, please make sure that the mobile phone is connected to the same WiFi network as your computer.

 

Displaying a Bitcoin transaction.

Note
Before using Secalot RemoteScreen to display Bitcoin transactions that you are signing, please make sure you are familiar with how to use Secalot with Electrum in general, as described here.

Make sure that Secalot Control Panel is running on your computer and that the RemoteScreen app is bound to it.

Start Electrum, and using it as normal, proceed to the point where you are asked to press a touch button on Secalot to confirm transaction signing.

Open the RemoteScreen app and verify that the status line is green and it can find your computer.

Press the “Get transaction details” button in the app. Your transaction details, including all inputs, outputs, amounts and a fee would be displayed.

If everything is correct, you can proceed to dismiss the dialog in the app and confirm signing with a press of a touch button on Secalot.

Note
Once you are prompted to press the touch button, you have 60 seconds to confirm. If the details displayed are not as you expected, please wait for the signing operation to time out without pressing a touch button.

 

Displaying an Ethereum transaction.

Note
Before using Secalot RemoteScreen to display Ethereum transactions that you are signing, please make sure you are familiar on how to use Secalot with MyEtherWallet in general, as described here.

Make sure that Secalot Control Panel is running on your computer and that the RemoteScreen app is bound to it.

Open MyEtherWallet, and using it as normal, proceed to the point where you are asked to press a touch button on a device to confirm transaction signing.

Open the RemoteScreen app and verify that the status line is green and it can find your computer.

Press the “Get transaction details” button in the app. Full transaction details would be displayed.

If everything is correct, you can proceed to dismiss the dialog in the app and confirm signing with a press of a touch button.

Note
Once you are prompted to press the touch button, you have 60 seconds to confirm. If the details displayed are not as you expected, please wait for the signing operation to time out without pressing a touch button.

 

Unbinding

At any time you can unbind your RemoteScreen app from a given device and a Control Panel instance. Just press the “Unbind” button on the top of the screen. This might be needed if you want to switch to using a different Secalot device with the app or perform transaction signing on a different computer.

From within the Control Panel, you can also unbind a mobile phone by pressing the “Unbind mobile phone” button on the “RemoteScreen” tab.