Hey all. Would you say keeping this seed in your apartment/house is safe at all?
The other thing is if you do this, wouldn't it make sense to keep a few phrases in one area, and the other in another area etc?
Depends. Are you more worried about your house burning down or about someone breaking in and stealing your seed?
The other thing is how many words are there? Thus its a 12 word phrase but how many words are there? The other thing im wondering is this.
Its 2048 different words[1].
Let just say your 12 word phrase is ... and im making this 12 word phrase up right now
dog cat ball cow mouse horse tv sofa bed table chair floor
So if this was a real 12 word phrase and you enter it on any computer, well you would open the wallet and have access to whatever bitcoin is in the wallet. But let say you rearrange these words around etc. Would that be possible for it to be a possible 12 word phrase for someone else? The thing is how many combinations are there total? Because couldn't one persons 12 word phrase possibly have say 3 words the same as another user? Or is this not possible?
The security of the seed for 12 words is 128 bit IIRC, which is roughly the same as a bitcoin private key. Its possible to have 3 identical words at the same position, but you still need to match the other 9 to have the same seed. To have the same seed is sufficiently unlikely.
Do any of the 12 word phrase from electrum or blockchain use the same words?
IIRC no other wallet uses the same words.
What if you know say the first 10 words of the 12 word phrase. Or if someone knows the first 10 words of the 12 word phrase. What are the chances that they could figure out the last 2 words of your wallet and have access to it?
Testing for 2 missing seed words and positions would not take long enough for it to be still secure. If you think you have lost 10 of your 12 seed words you should move to a new wallet with a new seed.
I heard someone mentioning brute force but not sure what that is exactly except i heard its like trial and error.
Its exactly that. Test one seed, derive the first x private keys and adresses, check for (historic) balance, repeat until all combinations have been tried.
But wouldn't someone need to enter each word that is not known etc? The other thing is after many tries, would you be allowed to make more tries etc? Like imagine you try to log into an email account. After many attempts, you wont be able to log in for a while etc.
You dont need the wallet software for that and I doubt anyone would want to try 2048 missing words for 12 positions, considering only 1 word and its position is unknown. Youd write a script or use an existing one. E.g. btcrecover has some capabilities to check for wrong seed words. It doesnt check against a balance, you need to know an address. For someone malicious it would be relativly easy to change this though.
How many words out of the 12 words would you say if someone had access to it or if someone forgot their electrum password, they can still recover their wallet etc?
Gut feeling here, 9 words would be feasible depending on the amount to recover and how much of it you want to invest it computers to recover it. One or two words should be possible on home machines given some time.
Does this differ if its blockchain or any altcoin wallet?
Not for blockchain no. The algorithms used are mostly the same. It would be possible to design a seed derivation algorithm that is slow and thus more difficult to brute force, but I dont know if anyone has done something like that.
Does anyone know if altcoins have 12 word phrases and if they do, do those words all come from the electrum words etc?
Electrum has several forks for alt coins, e.g. LTC, Doge(?) and BCH (if you consider it an alt).
[1]
https://github.com/spesmilo/electrum/blob/master/lib/wordlist/english.txt