On every page, there is a chance that you might get a key that has had transactions on it, or has bitcoin stored on it. This lures in newbies who spend computing power and time to try and find bitcoin wallets with currency on them.
However, the likelihood of finding one here, or any other similar website like this is extremely unlikely. The possibility is there, just insanely low odds. The keys that can be found here are ones with low entropy (randomness) and originate from keys generated by null inputs and brain wallets that have no passphrase of any sort. Of course, this doesn’t mean you can’t get anything worthwhile there.
Many wallet’s private keys have been discovered through shared computational power. In the end, a private key is just a number. Sifting through these keys manually, though, is extremely inefficient. The odds of more than one wallet randomly generating the same key are one in a billion-billion-billion-billion-billion.
Even if you have a supercomputer that goes through billions of keys a second, you have to wait billions of years which is outside the lifetime of any living creature on Earth. If current Bitcoin farms were able to brute-force keys at the same speed as they’re mining (and they’re specialized for mining to achieve this speed)
1. their hardware was 1,000,000,000,000 times faster
2. there were 1,000,000,000,000 as many of them
3. every human alive had these farms
This setup would be able to brute-force a specific key in a few billion years.
That should give an idea of how bad the odds are. However, quantum computing is a huge risk to the algorithms cryptocurrencies use to generate private keys and soon we will see currencies like Bitcoin and Ethereum adopting new algorithms to counter this risk. Quantum computers, through grover’s algorithm can turn a 256 bit search space(which all cryptocurrencies use) into a 128 bit search space which is still fairly secure and hard to break into. The biggest danger of a quantum computer is that it can easily break an asymmetric algorithm, for example ECC.
ECC is the algorithm bitcoin uses, but in a different implementation which slightly reduces the risk. Before you send bitcoin from one address, that address is unknown therefore impossible to crack into. When you send bitcoin from that address, the quantum computer has a window to get your private key, the time between the transaction being generated and it being confirmed in the blockchain. This doesn’t mean bitcoin is doomed though. Instead of a whole new algorithm, a protocol modification could do the job. We could see this being implemented soon as quantum computing becomes more and more mainstream therefore posing a higher risk.