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I am new to the whole Bitcoin thing, and I am having my first attempt almost going sour. I lost where I created my wallet. I have my Bitcoin address and only 11 of my mnemonic seed phrase words (of 12). I attempted using a word I thought was it and then recovered a wallet on bread wallet, but after sync in, it was still zero balance for hours. I contacted the support group and they told me that I had probably made a mistake.

What can I do?

  • 2
    When you say 'private keys', I assume you actually mean 'mnemonic seed phrase words', right? Private keys are long, random-looking strings of numbers and letters. Mnemonic seed phrases are composed of regular words. – chytrik Sep 6 '18 at 21:17
  • Yes i mean "mnemonic seed phrase words" and i have 11 words out of the 12 words – Perry Sep 6 '18 at 22:13
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If you are missing the first word and you know the rest of the 11 words, there are 2048 possible mnemonics but only ~128 of them are valid.

Using Python and this library you can print all the valid ones with this simple script:

from btctools.HD import check, WORDS

phrase = "{x} decrease enjoy credit fold prepare school midnight flower wrong false already"

for word in WORDS:
    mnemonic = phrase.format(x=word)
    if check(mnemonic):
        print(mnemonic)

The output is:

alcohol decrease enjoy credit fold prepare school midnight flower wrong false already
alien decrease enjoy credit fold prepare school midnight flower wrong false already
ancient decrease enjoy credit fold prepare school midnight flower wrong false already
animal decrease enjoy credit fold prepare school midnight flower wrong false already
apple decrease enjoy credit fold prepare school midnight flower wrong false already
baby decrease enjoy credit fold prepare school midnight flower wrong false already
bamboo decrease enjoy credit fold prepare school midnight flower wrong false already
become decrease enjoy credit fold prepare school midnight flower wrong false already
blanket decrease enjoy credit fold prepare school midnight flower wrong false already
body decrease enjoy credit fold prepare school midnight flower wrong false already
...

Then you can try them one by one to a wallet that support BIP39. Obviously change the last 11 words in my example with your words.

Good luck!

1

If you are missing just one word from a 12-word seed phrase, and you know the position of the missing word, then chances are you'll be able to recover your wallet. As Martin mentioned, if you are missing multiple words, or you do not know the position of the missing word, then the number of possible combinations increases greatly, perhaps to the point of it being computationally infeasible.

Here is a link to the BIP39 word list. If you remember anything about the word (eg, you think it started with an "a"), then you could just manually try recovering a wallet with each word that matches your suspicion (in combination with the rest of your seed phrase).

To run the entire list, you'll probably want to automate the process using some software to quickly iterate through the list.

-1

If you're referring to "11 Characters" of your Private Key- you are out of luck. Brute-forcing the missing characters is not possible, at least not in today's world.

If you're referring to "11 Words" from a Mnemonic Phrase, you are also out of luck. Factoring the astronomical number of possible combinations only a three, four, or five word Mnemonic can contain -, a dictionary attack to hash out the rest of the Mnemonic Phase would be very difficult, with each additional word needed (not sure if you had a 15, or 16 word Mnemonic), creating an massively exponential increase in solving using todays computing power.

Missing 1 Word of a Mnemonic, could be dictionary attacked on a modern PC workstation. Missing 2, nearly impossible unless you know how to dictionary attack, have your rainbow tables all ready to go, but 3 words or more? --There are simply to many possible words, not even including plurals, pre-fix changes, suffix changes, or the plethora of other linguistic alterations one can make to most words rendering it a completely different word altogether.

  • Yes i mean "mnemonic seed phrase words" and i have 11 words out of the 12 words – Perry Sep 6 '18 at 22:14
  • If you are missing one word, do you know if it is the last, first, or any specific word - by which I mean order... because order counts. That said - if you are missing the LAST word for example; you'd have to do a dictionary attack... which you'd have to know how to do. This would include running a wallet CLI on Linux, I'm guessing Linux Kali for an operating system (someone may want to chime in here as I'm not very familiar with bruteforcing techniques), but you'd essentially bruteforce the final word via CLI using a rainbow database of dictionary words (which you can find online). – McFlySoHigh Sep 6 '18 at 22:17
  • Its the first word – Perry Sep 6 '18 at 22:18
  • Then the same goes for what I've written right above. You'd need to try word after word, using a "dictionary attack" to attempt to find the correct missing word. An online wallet like BreadWallet is not an option, they have safeguards in place to prevent any such attempt and will ban you from trying more than a few times. So you'll have to do it via a wallet, which is fully synced, with a fast processor, and via CLI. And cross your fingers... that first word starts with an A, B, or C. – McFlySoHigh Sep 6 '18 at 22:23

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