Bitcoin Forum

Hi guys I lost my passphrase like an idiot. Good news is I remember part of it for certain. If anyone here can help me I'd love to tip that person, first off my password is either 1 of two things. It's either a set word with numbers and I fat fingered it when I was setting it and am off by a tad, or used an all number password that I forgot the middle of, I for certain know the first 4 digits and last 3 digits but don't remember how long the password is (most likely 12 characters total) If there is anyone here that can help please I would appreciate it greatly.

What was protected with the passphrase? If it is something local, e.g. an encrypted wallet - bruteforsing may be is possible. If it is something on the web, it would be much more difficult, because webservices don't let you make too many attempts.

It's local

had something simlar happen to me a few weeks ago. just had to scrap it and get a new one

I've got 19 bitcoins on the account I'd hate to scrap it considering what it's worth.

Doing a similar service for someone else right now. Cracking takes time. You need to do the following:
1) write down everything about the password you know
2) limit the search space by excluding possibilities
3) find someone to run the search (PM me if you can't find another trusted person)

if you know 7 characters for certain, that leaves you with a 5-dim search space. That's about a trillion possibilities, takes about 1 day on a 400-core cluster with 150 trials /sec/core.

I can say this for certain at this point. It's all numbers, no zero's though. I know 7 digits for certain. It's between 11 and 17 characters at most long. I know the first 4 and last 3.

With only 11 characters, if you remember 7 of them, it leaves 6,561 characters to try. Absolutely doable within a few minutes, if not seconds.
If it was 17 characters, and you remember 7 of them, it leaves 3,486,784,401 combinations possible.

Better be 11 characters.

Looks like you got professional help:

With 5 unknown characters, given they are all decimal digits it is exactly 100000 possible combinations (not much).

I didn't carefully read all available info. So we know that all unknown characters are decimal digits, but zeros are not used. In the worst case, if password length is 17 chars, that gives us 3.49 billions combinations, what is much worse. But still cracking seems to be possible imo.

#!/usr/bin/ruby -w

start = "pass"
finish = "word"

def test(phrase)
  print phrase, "\t"
  system("./bitcoind", "walletpassphrase", phrase, "20")
  case $?.exitstatus
  when 0
    puts "Found it!  #{phrase}"
    exit 0
  when 127
    puts "bitcoind not found in current dir"
    exit 1
  when nil
    puts "Aborting"
    exit 1
  end
end

(0..20).each do |length|
  [1,2,3,4,5,6,7,8,9].repeated_permutation(length) do |digits|
    test(start + digits.join + finish)
  end
end