Your question essentially boils down to whether someone can find a RIPEMD-160 collision.  Your address is a hash of your public key.  An attacker doesn't need to discover your private key, which has a probability of approximately 1 in 2²⁵⁶.  They need to find a private key whose public key generates the same 160-bit RIPEMD hash as yours.  The odds of this happening are 1 in 2¹⁶⁰.

This is still  astronomically large.  You can rest assured that your coins are safe. 

The scenario you described isn't possible because of how private keys are generated in cryptographic systems. I used to think about this a while agoo but after doing some research I found that the randomness used in generating keys for each wallet ensures they are always unique. This means it's not possible for two wallets to have exactly the same keys. Another thing I wondered about was how the cryptographic system can check if a key has been generated before, especially if it's done offline without any internet connection. Then it took a bit more time to know that it wasn't necessary to create a wallet online and you can also sign your transactions offline. Meaning that you can choose not to ever expose your keys to the Internet.


Is it possible for seed to be 100% protected? To me, it's not actually possible as there might be many open spaces that makes it 99% even when they have never seen an internet connection. But it now depends on how serious you take the security of your keys.(just my taught though)

Although it wouldn’t be totally correct to use the word impossible because theoretically there is possibility since there is nothing actually keeping tabs of the generated private keys to stop the generation of them.

But mathematically it is impossible to actually get the private key collision because the total number of private keys available is slightly less than 2²⁵⁶ which is definitely impossible to generate all at this rate. Even the possibility of generating same address which is smaller is still having to generate a 2¹⁶⁰ private keys before getting a collision. So let’s put out the impossibility now at this rate.


That’s basically just saying that nothing is 100% perfect which yea is right. But still your 99% is already showing perfection.

It might be possible by math since the chance don't fall to zero but it's very impossible to happen realistically. Your kind of concern were already thought by the those companies who have very huge BTC holdings. If you think about it, they as rich as holding hundred of thousands of BTC trusts the process from standard wallet generation how much more for those average holders?

It's impossible because the keys are generated with entropy and the odds to generate the same keys are just too low to consider it as an option. If someone was able to spend your coins, that means someone got access to your pendrive, that's the only logical version.

Or another option could be the fact that you used the wrong software to generate the private keys, some malware that sends the pk to the hacker when the address is generated.

This is my favourite analogy:


Another excellent analogy is provided by Charles-Tim in the first reply.  To put it into perspective, even if you used the most efficient method to, not hash, *just count* up to 2²⁵⁶ and had the energy equivalent of the Sun (roughly 330,000 times the mass of the Earth!), you would still run out of energy before reaching that number. 

Thank you All for detailed and great information. Now it's much more clear to me.