Reminder: Trezor Shamir Backup is fundamentally secure

So I was very active in this space during the last 2 days, and a lot of people claimed something similar to: “Trezor also has a similar backup feature”.

This is not true.

But let’s look into the facts. Trezor Model T has a function called Shamir backup, which has a nice info page here. This uses Shamir’s Secret Sharing to create a number of “shards”, and you can decide how many are needed to reconstruct the wallet. Here are a few very relevant details:

Shamir Backup is available as an option only once after you create your wallet. You decide if your Trezor shows you the seed words or the Shamir shares. They use an open source algorithm which is documented here. Anyone can verify it and the recovery outside of a Trezor hw-wallet is possible if required. The shares are displayed only on the screen of the device in seed words so they are easy to write down. Your shares and seed remain cold. Only you get in contact with your offline shares, and you are responsible for storing / hiding them.

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What Shamir Backup doesn’t do:

It does not create shares at any time later while using the wallet It does not send the shares to the PC It does not share your shares with some random companies

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tl;dr: Trezor did an excellent implementation of a great feature with Shamir Backup. It’s useful and fundamentally secure. Comparing this to a recently announced feature of a competitor is simply wrong.