The concepts behind blockchain technology make it nearly impossible to hack a blockchain. However, there are weaknesses outside of the blockchain that create opportunities for thieves.
Hackers can gain access to cryptocurrency wallets and exchange accounts of cryptocurrency owners to steal cryptocurrencies.The short answer, from many experts, is that the blockchain itself cannot be hacked.
But processes adjacent to the blockchain can certainly be hacked in a number of ways. Hackers have also been known to steal the keys to cryptocurrency wallets, the place where someone's balance is stored on the blockchain. Until recently, blockchain was seen as an unhackable technology that empowered and secured cryptocurrencies, but that's no longer the case. As we have seen, on the one hand, blockchain itself as a model is very resistant to almost all types of hacking.
However, it's important to keep in mind that when you hear about a cryptocurrency hack, it's not the blockchain that's being hacked, but the peripheral digital services, platforms, and networks that are hacked. Since there are several loopholes, from storing coins on an unsecure exchange to leaving your laptop unprotected, there can be several reasons why a bad actor can access your bitcoin wallet. Just as Bitcoin has never been successfully attacked at 51%, it has never been shut down, even for a short period of time. For example, Bitcoin and other cryptocurrencies are held in digital wallets and traded through digital currency exchanges.
Due to the underlying blockchain technology that cryptocurrency supports, in which data is not stored on a central server, but on a huge network of computers that constantly checks and verifies the accuracy of records, a hack would be quite difficult. And the very nature of public blockchains means that if there is a smart contract error, hackers will find it, since the source code is often visible on the blockchain. You may have come across several news stories pointing to how hackers stole millions of Bitcoins. By getting the majority on the computing power of digital currency, the hacker was able to defraud other users by sending them payments and then rewriting the existing blockchain ledger to cover their tracks, as MIT Tech explains.
Phishing, malware and key theft target exchanges and not the blockchain itself, as is the case with 51 percent attacks. Many players, such as government institutions and banking officials, have proposed shutting down the Bitcoin network before, but Bitcoin has operated with virtually 100% uptime for almost ten years. This is because most rely on blockchains that use proof of work as a protocol for verifying transactions. Smart contracts began to become more popular as people went deeper into cryptocurrency in the blockchain world.