guessing private key fear

[fred21]

Hello,

I have already had this discussion however I still have trouble understanding how can't someone with good computer can't get a private key of a BTC address with BTC on it and just withdraw the BTC.

Even if I have BTC on cold storage, what if someone get my private key by accident just by generating a new address on its own wallet.

this only a question of probabilities. Can you prove this will never happen?


thanks

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[mocacinno]

prove? No, it is indeed possible...
Each time you try, there is one chance in 1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976 that you find the exact private key belonging to a certain address.

The main problem here is that human minds are not capable of comprehending such numbers...
Are  you afraid of getting hit by lightning? Well those odds are 1 in 1,222,000 PER YEAR
Are you afraid of dying by being hit by a meteorite? Well those odds are 1 in 250,000 (in a lifetime)
source: https://stacker.com/stories/2343/odds-50-random-events-happening-you

If you live, for example, 70 years, the odds of being hit by lightning and later in your life dying because you were hit by a meteorite are 1 in 4.357.142.857. So it's 335426605300057279761503315041820000000 times more likely to have those two things happen, than it is to guess an exact private key...

Now, offcourse, there are estimated to be around 460.000.000 funded addresses (https://www.buybitcoinworldwide.com/how-many-bitcoin-users/). So, you have to divide 335426605300057279761503315041820000000  by 460.000.000 if you want to know how much the odds are compared to generating a private key for *any* funded address.
Then you end up with 729.188.272.391.428.869.046.746.337.047

Now, let's assume you're not generating one key, but you're able to generate 2002 Mk/s (https://en.bitcoin.it/wiki/Vanitygen), this is grossly exaggerated, since this vanitygen program only generates keypairs, but does not do a lookup for unspent outputs funding those addresses.
Let's see how big the odds are that you can find *one* private key belonging to *one* funded address in a lifetime of 70 years compared to getting hit by lightning AND dying of an astroid:
729.188.272.391.428.869.046.746.337.047 / (2002.000.000 keys/second * 60 seconds * 60 minutes * 24 hours * 365 days * 70 years) =
729.188.272.391.428.869.046.746.337.047 / 4.419.455.040.000.000.000 =
164.995.065.181

CONCLUSION:
It is 167 billion times more likely to be hit by lightning AND dying from a meteorite strike than it is to run a GPU 24/7 generating address for 70 years and finding a single private key whose public key hash was once funded

I don't know about you... but i like those odds... Sure, they are not 0, they'll never be 0, but nothing in this life is absolute... I am very sure the odds of somebody impersonating you and stealing all your money from your bank account is much, much higher than somebody robbing you from your bitcoin... The odds of your bank vault being opened during a bank robbery and your gold being stolen is higher than the odds you get robbed out of your bitcoin... Hell, the odds of your country dissapearing and your money not being worth the paper it's printed on is much higher than your bitcoin being stolen.... At least, in a perfect world... In reality most people get robbed because they used a weak RNG, a vulnerable wallet, an infected pc, fall victim to phishing, fall victim to an evil maid,...

[NeuroticFish]

@mocacinno already gave you the best answer, comparing the chance of having your private keys guessed with the chance for other ..."events".
I'll only add that if the funds are so big and this can make you sleep better, try to split them safely (!!) into a few more addresses (or even seeds). However, that would mean more things to take care of.

[LoyceV]

CONCLUSION:
It is 167 billion times more likely to be hit by lightning AND dying from a meteorite strike than it is to run a GPU 24/7 generating address for 70 years and finding a single private key whose public key hash was once funded

On top of that, if you're going to use a lot of computing power, it's much more profitable to mine Bitcoin blocks than to try and find a funded private key.

In the long list of things that are much more likely to find: try to guess my creditcard number. Then guess my phone number and give me a call. If you do, please guess the winning lottery numbers for me. All this is still much more likely than finding a funded private keys.

[fred21]

So this is interesting.

is it better to spread BTC on several addresses than leaving on one?

and

is it better to spread BTC on several seeds than on several addresses of the same seed?

thanks

[mocacinno]

So this is interesting.

is it better to spread BTC on several addresses than leaving on one?

and

is it better to spread BTC on several seeds than on several addresses of the same seed?

thanks

Did you read my post? Did you try to comprehend those numbers?
It's more important to use a good wallet (with a non-flawed RNG) and make sure your private key/seed doesn't get stolen in any way (including saving on a potential online medium, virusses, malware, fake wallets, phishing,..) than it is to split up your unspent outputs... Really... If you're not afraid of dying due to a meteorite after being hit by lightning, you defenately should not be afraid of somebody guessing your private key... Be afraid that somebody STEALS your wallet file, or STEALS your seed/pk, don't be afraid that somebody GUESSES your private key.

By splitting up, you can decrease the odds of somebody STEALING your wallet/seed/pk IF (and only IF) you use different devices and wallet to generate those seeds/keys and never store them in the same place... It adds a whole lot of extra things you should keep in mind... It might be a good idear if you're at risk of somebody stealing your wallet/seed/pk, but for a normal user, the risks of messing up the whole setup might be bigger than the risk of somebody stealing your key/seed/wallet.

My advice would rather be to use a verified method with good OPSEC and stick to it... Generate your seed/wallet/pk on an offline machine, never let it touch any online machine, use a decent wallet and verify this wallet before using it, ignore any attempts of social hacking, keep encrypted backups on offline media,... As a normal user this adds much more certainty than starting to generate loads of seeds using different wallets and different OS's, then keep them safe on different offline media... This might be a good idear if you're running an exchange with several employees, but as a private user it might lead to loss of funds due to forgetting your encryption scheme/wallet/backup/...

You're not wrong about the odds of somebody guessing your private key not being completely 0... It's just that you have to protect yourself against the threads with the biggest odds... And the thread of somebody guessing your private key is soooooo close to 0, that in reality you could say it IS 0. The odds of you being scammed or your wallet/seed/pk being stolen are not 0... I read those stories every single day... Build up good OPSEC against those threads instead of focussing on the one thread whose odds are in reality ~0 .

[fred21]

@mocacinno

thanks, I read your post and thank you for spending time to write this.

I am very careful about my funds.

I use bitadress.org offline or Ian coleman wallet offline. I don't use software wallet.
I use coinb.in offline to generate and send transaction.

I store my encrypted seed and encrypted private key (BIP38) on paper, on a drive and on google drive (3 copies)

I always put flight mode on my computer and use private browsing on firefox before using bitaddress.org or ian coleman wallet or coinb.in.

And I always close firefox, delete unemcrypted files, empty the trash before removing plane mode on computer.

[bittraffic]

Its what I also thought when I saw that I only have 12 words seed, it seem easy to mix and guess some private keys.

But seeing mocaccino's reply seem safe. The chances of lightning hitting on me is very close to zero, its not encouraging to someone who wants to keep guessing all day but end up wasting his time.  Would it be worth for the security of our funds to distribute our most prized asset to 2 or 3 BTC addresses?

[LoyceV]

I use bitadress.org offline or Ian coleman wallet offline. I don't use software wallet.

That's more or less the same as using a software wallet.

I use coinb.in offline to generate and send transaction.

If you want to be very careful, it doesn't hurt to verify your signed transaction with other software (Electrum for instance) before broadcasting it.

I store my encrypted seed and encrypted private key (BIP38) on paper, on a drive and on google drive (3 copies)

The risk of someone compromising your Google drive is much more likely than someone randomly finding your private key.

I always put flight mode on my computer and use private browsing on firefox before using bitaddress.org or ian coleman wallet or coinb.in.

That's another risk: malware could patiently wait until your computer goes online again. Using a LIVE Linux DVD that runs only from memory (obviously offline) is much safer.

And I always close firefox, delete unemcrypted files, empty the trash before removing plane mode on computer.

That's probably safe, but you can't be absolutely sure. The computer you used to handle offline keys should never go online again.

[DaveF]

The computer you used to handle offline keys should never go online again.

The computer is fine to go online again after the drive has been removed and reformatted with a hammer.
I have tried to explain to people that once you remove the drive there really is nothing in the machine that matters to your security anymore.
Yes it's a minor thing, but it's something I have to deal with a times so I really want people to understand.

-Dave

[fred21]

The risk of someone compromising your Google drive is much more likely than someone randomly finding your private key.

Yes I agree, but my private key are BIP 38 encrypted or my seeds are on txt file and AES encrypted on google drive

That's another risk: malware could patiently wait until your computer goes online again. Using a LIVE Linux DVD that runs only from memory (obviously offline) is much safer.

That's what I am fearful of. I have only one computer. If I buy new computer, it will always need to be connected to internet for OS update. Any ideas?

[NeuroticFish]

The computer is fine to go online again after the drive has been removed and reformatted with a hammer.

That's why best way to handle this is with a live Linux USB stick and with no persistence.

Maybe somebody will convince the guys from Tails to add a copy of Ian Coleman BIP39 tool for this purpose 

is it better to spread BTC on several addresses than leaving on one?

Not necessarily. But it can help you sleep better if you don't trust the numbers provided.
Something like the belief that "the lightning doesn't strike twice in the same spot"

[LoyceV]

That's what I am fearful of. I have only one computer. If I buy new computer, it will always need to be connected to internet for OS update. Any ideas?

Download and burn a Knoppix or Tails DVD, boot from that DVD, and use the preinstalled Electrum or bitaddress.org or coinb.in from a USB stick without going online.
When you're done, turn off your PC to wipe everything from memory.

[o_e_l_e_o]

mocacinno has already given a good explanation of the numbers involved, but here's a post I made on this topic a while back:

The whole security system for bitcoin is not that it is impossible (which would be good) but that it is vvvveeerrryyy unlikely.

It is impossible to have a security system which is impossible to hack, and as far as security systems go, bitcoin's is pretty darn good.

Given that most 2FA codes are 6 digits long, there is a 1 in 10⁶ chance of someone guessing your 2FA code.
Assuming an average house lock as 8 tumblers, and each tumbler can adopt one of 10 positions, then there is a 1 in 10⁸ chance that someone will be able to guess your exact house key shape and unlock your door.
Given a standard credit card has a 15 or 16 digit number on it, there is at most a 1 in 10¹⁶ chance that someone will be able to guess your credit card number.
If you use a password manager to generate a long and totally random 16 character password, drawing from the full ASCII 95 character set of upper and lowercase letters, numbers, and symbols, (e.g. CY\u4"=t{rV%;N9S), there is a 1 in 4.4*10³¹ chance of someone guessing it.
The chance of someone guessing your private key is 1 in 1.158*10⁷⁷.

The chance of someone correctly guessing your password, your 2FA code, your credit card number, and the key to your house simultaneously is 4.4*10⁶¹, which is still around 2 thousand trillion times more likely than them guessing your private key.

The TL;DR is that if you are worried about someone guessing your private key, then you should be paralyzed in fear about someone guessing all your account passwords, your credit card number, your social security number, the specific radio frequency to steal your car, or pretty much anything else you keep protected, lock up, password protected, etc. All are magnitudes more likely than someone guessing your private key.


You are far more likely to have your coins stolen from your poor security practices.

I store my encrypted seed and encrypted private key (BIP38) on paper, on a drive and on google drive (3 copies)

Storing anything in the cloud is a risk. I would stop doing this immediately, and consider those wallets compromised and move the coins out of them. Storing on a drive is only safe if that drive remains encrypted at rest and is never part of a computer which will ever go online again.

I always put flight mode on my computer and use private browsing on firefox before using bitaddress.org or ian coleman wallet or coinb.in.

Private browsing achieves literally nothing in this set up. Putting an online computer on flight mode also changes very little, as any half decent malware which requires an internet connection to transmit data will simply wait until you go online again.

And I always close firefox, delete unemcrypted files, empty the trash before removing plane mode on computer.

Do you overwrite the sectors of your hard disk which held the unencrypted data with junk data? If not, then you haven't actually deleted anything.

[fred21]

I store my encrypted seed and encrypted private key (BIP38) on paper, on a drive and on google drive (3 copies)

Storing anything in the cloud is a risk. I would stop doing this immediately, and consider those wallets compromised and move the coins out of them. Storing on a drive is only safe if that drive remains encrypted at rest and is never part of a computer which will ever go online again.

My seeds are encrypted with AES (https://www.aescrypt.com) and private keys are BIP38 encrypted. Even if someone breaks in google drive, he will not be able to get private key because of that.

Moreover, I will not keep my keys in one drive because of hard drive failure, fire, flood, robberies.... I have to keep one copy off site.

[BlackHatCoiner]

My seeds are encrypted with AES

Alright, Google can't view your private keys. But, you need Google to view them, right? What happens if Google suspends your account, or decides within the next 5 years to shut down Drive?

Moreover, I will not keep my keys in one drive because of hard drive failure, fire, flood, robberies.... I have to keep one copy off site.

But, you still have to keep those keys somewhere electronically, right? Do what LoyceV recommended you above and write down the seed phrase in a piece of paper or in a stainless steel. You, then, won't worry for drive failures neither fires or floods. (If done using the latter)

[o_e_l_e_o]

My seeds are encrypted with AES (https://www.aescrypt.com)

AES is an encryption standard. AES Crypt is a piece of encryption software.

AES Crypt has had a number of issues identified with it which have not been resolved: https://www.reddit.com/r/privacytoolsIO/comments/b7riov/aes_crypt_security_audit_1_serious_issue_found/. Even if they were all resolved, do you completely trust this software? You know there are no other flaws or vulnerabilities in it? Have you reviewed the code yourself?

The security of anything you store in the cloud is poor, at best. As soon as you upload something to Google Drive, it is duplicated on an unknown number of servers across an unknown number of countries and can be accessed by an unknown number of people.

I have to keep one copy off site.

Correct. So write it down on paper as pretty much every good wallet suggests you should do. No good wallet suggests storing your seed phrase online.

[erre]

Don't worry, your money is secured by the law of universe