How can you hack the bitcoin system

Bitcoin is a cryptocurrency which became very popular in the past recent years. It was claimed that it is using the technology which can never be hacked by someone at any cost which is blockchain.But today i am going to reveal this truth that blockchain system can be hacked but it requires resources. If you want to destroy the bitcoin system at any cost then you can try this method. Basically this network is composed of blocks which are connected to each other and each successive member contains the hash of the previous block. The block which initiates the chain is termed as genesis block. the most important thing a genesis block contains is "Nounce". It is just a value which can be set by the developer who is going to initiate the blockchain. This value is always remains secret by the developers because it is the one of the main point of failures a blockchain can face. There is an another important aspect which is needed to be considered when you are planning to hack a blockchain system which is number of nodes. In order to hack a blockchain system you first need to know the Genesis block values and you should have sufficient resources to generate a more longer chain of blocks then the original system. at that instant the number of blocks in your chain crossed the numbers from the real chain, main system will be under your control. It seems to be easy but the estimated cost required to do this is much more than the amount you will get by hacking the system. therefore it is said that blockchain based systems are secure and they can not be hacked.