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Bitcoin => Bitcoin Discussion => Topic started by: BlockCheney on August 10, 2021, 09:39:37 PM



Title: Is this correct concerning BIP39 seeds?
Post by: BlockCheney on August 10, 2021, 09:39:37 PM
I saw this on Amazon product description. Is it true that you can re-create the phrase that way?

https://i.ibb.co/YL74B4L/Bildschirmfoto-2021-08-10-um-19-16-07.png


Title: Re: Is this correct concerning BIP39 seeds?
Post by: ranochigo on August 10, 2021, 11:22:07 PM
Assuming that the way the seed is generated is compliant with BIP39 and uses that word list. BIP39 states:

- the wordlist is created in such a way that it's enough to type the first four letters to unambiguously identify the word

The wordlist within the BIP fulfills this criteria.


Title: Re: Is this correct concerning BIP39 seeds?
Post by: Charles-Tim on August 11, 2021, 12:35:06 AM
Assuming that the way the seed is generated is compliant with BIP39 and uses that word list. BIP39 states:

- the wordlist is created in such a way that it's enough to type the first four letters to unambiguously identify the word

The wordlist within the BIP fulfills this criteria.
Even in electrum, first four letters to each word will give you each full word.


Title: Re: Is this correct concerning BIP39 seeds?
Post by: ranochigo on August 11, 2021, 02:22:20 AM
Even in electrum, first four letters to each word will give you each full word.
Electrum inherits the word list from BIP39. While the generation is not done in the same way, the fact that they have the same word list will result in them meeting the criteria set forth in the BIP.


Title: Re: Is this correct concerning BIP39 seeds?
Post by: NeuroticFish on August 11, 2021, 08:25:33 AM
Is it true that you can re-create the phrase that way?

I'd say that the wording "re-create" is not that much accurate and can be misleading. You seem to not be aware that the BIP39 seed is based on a fixed word list, not the full English dictionary.
And as said, the first 4 letters of each word are enough for saving the seed.


Even in electrum, first four letters to each word will give you each full word.

Indeed. And hardware wallets too. When I had to recover my seed on my Nano S this came pretty much handy.


Title: Re: Is this correct concerning BIP39 seeds?
Post by: khaled0111 on August 11, 2021, 11:47:30 PM
You've got your answer but I just want to add that this is not a safe way to back up your wallet seed.
It's true that you only need know the first 4 letters to identify a bip39 word but to recover your wallet you need to have saved those letters correctly.
Let's assume one of the seed words is "present", the first 4 letters are "pres". If you mistakenly save it as "pris", you'll end up with a totally different word when you recover your wallet which is "prison"!


Title: Re: Is this correct concerning BIP39 seeds?
Post by: NotATether on August 12, 2021, 01:11:14 AM
It is extremely risky to write down a seed phrase with just 4 letters in each word. The latter letters are there for redundancy in case you write them down in sloppy handwriting or typing and misspell some letters, tap the wrong keys, or write a letter in such a way that it looks ambiguous to another, making it all the more likely you will forget some words from your phrase.


Title: Re: Is this correct concerning BIP39 seeds?
Post by: DarkDays on August 12, 2021, 10:41:31 AM
You've got your answer but I just want to add that this is not a safe way to back up your wallet seed.
It's true that you only need know the first 4 letters to identify a bip39 word but to recover your wallet you need to have saved those letters correctly.
Let's assume one of the seed words is "present", the first 4 letters are "pres". If you mistakenly save it as "pris", you'll end up with a totally different word when you recover your wallet which is "prison"!
I agree that this is not the way to safely store a key phrase, and this is because of the words similarity. While the first 4 letter of the word might be enough to identify the word you can't recover the key phrase if those 4 letters for each word are not correct.

So makes no sense to correctly write the first 4 letters of each word and then use this system when you might as well copy correctly the full words.

This is mainly advice for new people looking to secure their crypto assets as too often you find that the seed phrase was not written down (or stored in any way) and lost their funds.


Title: Re: Is this correct concerning BIP39 seeds?
Post by: DaveF on August 12, 2021, 11:31:04 AM
As others have said yes you only need the 1st 4 letters.
And yes, it's not a good way of doing it due to the fact that you can mess it up or have some sloppy / ambiguous letter.

However, if you do make more then 1 copy you do mitigate that risk somewhat, as you can have 1 copy in a vault someplace and another stuck to the back of your refrigerator so if you mess one up you still can look at the other one.

In theory you should do this anyway. Even if you write dome all the words. Never rely on just one copy of there are life altering funds stored.

-Dave