User manual:Creating a wallet with Super Shamir

From Trezor Wiki
Jump to: navigation, search
Trezor Wiki/User/User manual/ Creating a wallet with Super Shamir
SS diagram1.png
Super Shamir scheme example

This article aims to provide a simple step-by-step manual for creating a new wallet utilizing the advanced Shamir Backup scheme called Super Shamir.

For detailed information about this method of securing your wallet, see Super Shamir and Shamir Backup.

NoteThe Super Shamir feature is currently available only for Trezor Model T and can only be activated using the command line client.

If you wish to create a single-level Shamir Backup scheme, see Creating a wallet with Shamir Backup.

Important remarks before you start[edit]

  • You will be presented with sequences of random 20 or 33 English words, each displayed on the screen of your device. These words will never be shown on your computer screen. Do not use backups offered to you by your computer.
  • The word-sequences are referred to as "recovery shares". If used correctly, the recovery shares can later be used to recover a wallet in case of theft, loss, or destruction of the Trezor device.
  • Keep the recovery shares written offline. Do not take pictures of your recovery shares, do not make digital copies of your recovery shares, and never upload them online.

Use paper or other more suitable platforms to keep your recovery shares offline. You can print and use the Shamir Backup Shares Sheet to make the writing process more convenient and organized.

  • The recovery shares will only be presented once and then never again. It is not possible to have the device show the words ever again. Pay close attention to every word and make sure you write them down correctly and in the right order.

Generating a new wallet[edit]

Use the following commands in Trezor command line client to create a wallet a preferred configuratioN:

trezorctl reset-device -b advanced for Super Shamir using shares made up of 20 words (128bits of entropy)

trezorctl reset-device -b advanced -t 256 for Super Shamir using shares made up of 33 words (256bits of entropy)

See Using trezorctl commands with Trezor for more options.

Backing up the wallet[edit]

Begin the process of backing up the wallet using the touchscreen on your Trezor device.

Read the Terms of Service and confirm that you wish to generate a new wallet with Shamir Backup by tapping the green checkmark button

Tap the greenBack upbutton to create a backup for your wallet now. You can also skip the process, use the wallet and return later. Be aware that you will only have a chance to back up your wallet once.

You are presented with a checklist of steps you will go through. Tap the greenContinuebutton to continue.

First you set the preferred group arrangement.

Select the number of groups you wish to create. The Super Shamir setting allows for minimum of 2 groups. The maximum number of groups is 16.

Continue by setting the group threshold. The group threshold defines how many groups have to reach their individual thresholds in order to reconstruct the wallet.

Now you start setting the individual groups. Each group can consist 1 to 16 shares. Each recovery share will consist of [English words].

Set the preferred number of shares you wish to generate in the first group and tap thebutton to continue.

Set the threshold for the first group. Threshold will specify the number of shares required to reconstruct the group.

The lowest possible threshold is always **two shares**. The maximum is the total number of generated shares (e.g., 5 of 5 or 16 of 16). Any of the generated shares can be used to fulfill the threshold. Set the threshold and tap onContinue.

Repeat the same for all other groups. Choose the number of shares to be generated and set the necessary threshold the individual groups ought to reach.

Prepare to write down the words of all generated shares. Take your time and proceed with caution.

ImportantReserve enough time to write down the shares. If you interrupt the connection at any point during this process, you will have to start again from the beginning. Mind that setting up bigger schemes, e.g., 3 groups with 10 shares means that you have to write down 600 words precisely and in perfect order.

Confirm that you understand that you should never make a digital copy of your recovery shares and never upload them online by tapping onI understand.

The device now presents the words of first share of the first group. Write down the words in the presented order and swipe to see the next few words. When you are done writing down the words,hold to confirm.

To help you check the valid order the sequence, the Trezor device picks 3 random words of the recovery share and asks you to select the one corresponding instructions on the display. There are three such checks for each recovery share.

Continue until you have all shares written down and checked.

After you write all your shares down, you will be presented with a confirmation screen. Finally, tap onContinueto finish backing up your wallet.

You are done! Good job!

Like Trezor? Get one here!