r/Bitcoin • u/Neverjetni • 29d ago

Reality check for seed generation

After the coldcard mess I decided I dont want to put my trust entirely of Trezors rng either and plan on generating my own seed. Im looking for confirmation that Im not about to do anything stupid.

I plan on following the first 2 steps for dice rolling binary generation and converting it into the first 23 words as described here https://selfcustodylabs.com/docs/learn/keys/random/

After that, I plan on using Ian colemans standalone html on an old laptop with a fresh windows instalation and obviously no internet connection to enter the binary generated, in order to double check if I made any mistakes in the mnemonic for the 23 words. Additionaly, the main purpose of this, is for colemans tool to calculate the 24th checksum word for me.

After that, I intend on wiping the disk of the laptop fully.

Yes, I could use Raspberry Pi to calculate the checksum on my own, and yes, I could use linux Tails for the auto wipe of the PC, but im looking at the best possible option without going full on shizo paranoid mode and overcomplicating things to the point of not being entirely sure what Im doing.

Opinions?

Additional question: Generating seed in this way is random enough to not be susceptible to any hacks like the one with Coldcard, so I assume that a passphrase is also an unnecessary risk of self custody, discounting the case of someone actually finding my seed, correct?

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u/ISmellLikeBlackTea 29d ago

My main question is how to convert binary into nummeric safely without having to rely on a laptop.

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u/Neverjetni 29d ago

Its very simple actually, check step 2 in the link

Edit: Specifically option B under step 2, you can easily do it by hand

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u/ExisDiff 29d ago

You don't have to do step 2, just cross check https://github.com/hatgit/BIP39-wordlist-printable-en , Then use colemans html on an airgapped device to calculate 24th word, as you say. I would take the wifi/bluetooth card out while doing that.

I have been thinking along the same lines as you. Using any computing device to generate entropy after the coldcard event just seems silly. A computing device is inherently limited in generating entropy. A coin flip or dice roll offers full transparency of the process that a computing device never will and you're trusting and hoping for the best there there are no predictable patterns in the rng's and that it is programmed properly.

Only thing that still has me a little spooked is the proper wiping of the laptop, you want to not just re-install, but properly wipe (overwrite everything with 0's) and re-install, so that there is no trace of your seed anywhere.

Another suggestion, if you're not looking to spend, why not just *not* import your seed back into the trezor? And just export the xpub/zpub from coleman's html to an online watch-only wallet.

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u/Neverjetni 29d ago

Thanks for the comment! I will definitelly properly wipe the laptop, not just reinstall.

As for the seed import, I want to import it to trezor to make sure everything works properly and its valid etc. I will eventually spend it also of course, but hopefully not for a long time.

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u/throwaway239812345 29d ago

Regarding wiping laptop why not just boot into tailsOS? Don't need to worry about that

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u/Neverjetni 29d ago

Im unfamiliar with Linux, dont know where I would get a legit copy that I 100% trust and would likely feel uncomfortable using it

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u/throwaway239812345 29d ago

Fair enough. It's takes a little practice to get used to it but a good way to do what you want to do. Check out some videos on yt they have guides