Two weeks ago I attended the presentation of SatoshiLab's latest hardware wallet, the Trezor Safe 7, and I will be sharing random thoughts. Here the first one:
SLIP39 (Shamir Secret Sharing or multishare backup).
In 2013, Trezor founders pushed the first draft for what became known as BIP39, a way to encode binary data in a human-readable format as a simple list of words. For context, at that time HD wallets didn't exist yet—or at least I don't recall any—and backing up your Bitcoin wallet meant simply making copies of your wallet files. While BIP39 is just an encoding mechanism that could theoretically encode any binary data, in practice it's used to encode the master seed for hierarchical deterministic wallets.
The first hardware wallets had only two buttons and very limited displays, so they needed a user-friendly mechanism to allow users to back up their seeds. BIP39 was perfect for this, and I believe—though I could be wrong—that this was the main goal of the BIP. Regardless, BIP39 was massively adopted, and currently every wallet I know of uses it, whether software or hardware.
As a wallet developer, I know that backing up wallets is perhaps the first and most important thing to implement, and also one of the most difficult, because there's no standard for saving metadata. The only thing that really works and is interoperable is BIP39.
Now SatoshiLabs has decided to make SLIP39 the default backup mechanism for the Trezor Safe 7, which surprised me. While I believe this is the right decision and SLIP39 is more flexible and generally superior, moving away from the most widely-used backup technology in the entire crypto space requires a level of courage that's somewhat unusual.
Disclaimer: I implemented SLIP39 in Wasabi Wallet with financial assistance from SatoshiLabs via a grant. While I would have implemented it regardless because it's been on my wish list for years, the grant certainly made it easier. I'll be making Wasabi use SLIP39 by default soon as well.
