Subnostr

Who can explain me this? #asknostr

nostr:npub17u5dneh8qjp43ecfxr6u5e9sjamsmxyuekrg2nlxrrk6nj9rsyrqywt4tp evaluates passphrase backups as "mediocre" and considers SeedXOR the superior alternative. He argues that passphrases are flawed due to their 2-2 setup, posing a risk of losing funds if one part is lost. Nevertheless, the same vulnerability exists for SeedXOR (2-2, 3-3, …). I don’t see any downside as long as the passphrase has a 256 bit entropy. Multiple backups are essential for both solutions.

Lopp on Passphrase backup:

„This gives you a security model that's the same as a 2 of 2 multisig setup. Do you know why 2 of 2 multisig isn't popular? Because it has 2 single points of failure - if you lose either part, you're screwed. I've seen quite a few people over the years get locked out of their funds because they forgot or lost the passphrase that accompanied their seed phrase.“

Lopp on SeedXOR backup:

„Seed XOR is, in my opinion, a superior way to achieve the properties that folks try to get with a "25th word passphrase" or via naive seed splitting, while decreasing the complexity and improving plausible deniability. Note that this is essentially an N of N (2-of-2 / 3-of-3 / etc) split backup, so you're going to want multiple sets of XOR'd backups to ensure that losing a single plate doesn't cause catastrophic loss.“

Source: https://blog.lopp.net/how-to-back-up-a-seed-phrase/

Rob 2y ago

Not using a passphrase decreases the complexity and points of failure of the setup, which he values more than outright security, since a complex (secure) setup is useless if you forget or lose access to the details, and is best left to advanced users, or the company he works for - wink.

He's writing to the masses, where an XOR'd set of seed words lets you have a simpler setup, easy to restore, and also includes plausible deniability since each of the XOR seed plates is a valid set of words by itself. An attacker has to know it's one of a set to know there's a larger wallet elsewhere.

The seed+passphrase setup is similar, in that you can load funds onto the seed-only wallet, and you keep the passphrase safe for the "real" wallet. But an attacker now has your entire seed phrase.

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Discussion

StackSats ⚡️ 2y ago

Thank you for your response. Here my comments to that:

1) Passphrase and SeedXOR have similar complexity. I understand the point, that more complex solutions increase the risk of loss due complexity. Anyhow, that has nothing do to with my question.

2) Why is a SeedXOR easier to restore? Please explain.

In my opinion Passphrase is easier to restore and supported by most wallets.

Furthermore the seed phrase of a passphrase secured wallet has the same deceive feature as the seed of a SeedXOR. You can load both with „ready to lose funds“ to deceive an attacker. The attacker doesn’t know that a bigger wallets exists in both cases.

3) what is the difference in the attacker having the seed phrase of a 256 bit passphrase wallet or a seed phrase of a SeedXOR wallet. Please explain.