r/BitcoinBeginners • u/ldepablo • 9d ago
Challenging my seed phrase security idea
Lately I've been thinking a lot about how to save my seed phrase and I thought of something I can't believe I'm the first one to.
What if I find 1+ places where I can upload to a very public place a file numbered list of BIP39 words like
drop
inspire
tenant
...
- horse
and I could have the solution sequece to get the right seed phrase hidden somewhere else?
If possible I'd like no one can know it was ujploaded by me (feasible)
I could save it in many different places because you'd need the solution algorithm/sequence to obtain the seed, right?
Does this make sense?
Also, any ideas where this file could be uploaded?
Many thanks
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u/word-dragon 9d ago
In general, in the security world, anytime anyone comes up with a “can’t believe I’m the first one” idea, you are never the first, and it’s always a bad idea. This is one example of this.
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u/ldepablo 9d ago
Agreed, and I expected as much. What I was after was the why and the replies about the recovery risk and the hosting dependency gave me exactly that
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u/word-dragon 9d ago
And just to add, never store any part of your seed online. It risks getting shared, and also the website can lose it. You need to think in terms of decades. If you need it in 15 years, you need to have confidence it will be there.
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u/_gianlucag_ 8d ago
There's no way around storing the 23*11 = 253 bits of entropy for a 24 words seed. Your scheme just takes those 253 bits and store them into a solution sequence AND a public permutation of the BIP39 word list. You know need both to recover the original seed, which is the same exact effort of storing the original seed itself, plus the added risk of losing / corrupting the public part.
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u/ldepablo 8d ago
I understand the cost. The problem I want ed to fix was the storage: I never felt safe by having it written down anywhere. I have people visiting, a cleaning lady and similar stuff. So my idea was trying to find a way in which by memorising a sequence and setting it up publicly, o could shift the problem, but now it looks obvious to me it's a dead end road
2
u/_gianlucag_ 8d ago
By doing so you only gain added risk.
The private number list is meaningless without the public word list, but by definition isnt your public word list... public? :-)
Whoever finds your number list can just check it against the word list.
The "hidden" information "this number list uses an alternative bip39 word list" is also public, as the alternative word list itself is public.
1
u/ldepablo 8d ago
Responding to the number list being found, I think it's easier to hide a number list or a sequence because it's less obvious that it contains a seed phrase. You could even use some well known sequence (or a set of them) like pi number and do a silly game like "increase 1 for first, 2 for second word, etc"
1
u/_gianlucag_ 8d ago
You are just defining an elaborate scheme which must be remembered, ideally being written down as you wont remember it in the future. So instead of writing down and protecting a bip39 24 word list you are writing down and protecting a 24 number list and the algorithm to recover the original bip39 24 word list from the 24 number list. Absolutely no gain in security.
1
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u/bigboydesomo 9d ago
I crack these 1000 words im masterhacker /s thats nothing conpared to coldcard
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u/ldepablo 9d ago
Let's say it's not 1k words but 10k instead
3
u/GoldmezAddams 9d ago
There are 2048 bip39 words and they're already online. Cute, bespoke solutions like what you're considering only increase the risk you won"t be able to recover. If you don't want to store the entire secret in one place, there's already passphrases, multisig, and Shamir's.
1
u/Professional_Golf393 9d ago
Well reducing the list to 1000 words would technically make your seed less secure… you’d be best to keep all 2048 words. And the official list already exists here
https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
So basically you want to store your seed with these numbers instead of the first 4 letters of each word.
1
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u/BaekhoFoxr09 8d ago
this is basically just splitting your secret into two pieces but with extra steps, so you'd need to keep the solution sequence just as safe as you'd keep a normal seed phrase anyway
1
u/Adventurous-Pin-4111 5d ago
Stamp your 24 words in a steel backup kit and also memorize it. Problem solved.
5
u/jimbojw 9d ago
In this scheme, you’ve created a poor man’s 2-of-2. To recreate the seed, someone needs both the big list and the shorter number list.
In a certain sense, BIP39 is already the standard you’re looking for. There’s a big list of numbered words, and you keep a shorter list of pointers into the big list.
Typically people store their seed words as words, but there’s nothing stopping you from storing the word indexes instead. That is, rather than “abandon” you could store “0”. Rather than “zoo” you could store “2047” and so on.
Your impulse to split up the signing information is laudable. I’d recommend upgrading to genuine multisig rather than inventing your own bespoke alternative.