The blockchain is a chain of blocks, this technology was originally described and developed in 1991 by a group of researchers and was originally intended to timestamp digital documents so that is not possible to backdate them or tamper with them. From that date, it was almost unused till 2009, when “Satoshi Nakamoto” used this technology for his digital cryptocurrency Bitcoin.
The blockchain is a distributed ledger and is completely open to anyone and anywhere. They have an interesting property, once a data is recorded inside a blockchain, it becomes very difficult or even not possible to change it.
Now let’s take a look at inside a Block and learn more about it. Each block contains some Data, the Hash of the block, and a Hash of the previous block. The data that stored inside the block depends on the type of blockchain, the Bitcoin blockchain for example stores the details about the transactions here, which are the sender, receiver, and the amounts of coins. A block has also a Hash, you can compare a hash to a fingerprint, it identifies a block and all of its contents and this is always unique just as a fingerprint. once a block is created its hash is being calculated, changing something inside the block causes to change the hash of block, so in other words, hashes are very useful when you want to detect changes to block, so if the fingerprint of a block changes so it is not more the same block. The third element inside each block is the hash of the previous block, and this helps effectivity to create a chain of blocks and this technic makes the blockchain so secure.
Nowadays computers are very fast, so if someone wants to hack one of the blocks in the blockchain, they can easily recreate all other following blocks, so all hashes are valid again, it will be under some seconds so a hacker can easily change the data of a Blockchain and use it for himself, so the hash of blocks is not enough to make a Blockchain secure, so there is another mechanism calls Proof of Work for every blockchain, which does not allow to recreate new blocks under 10 minutes ( for example in Bitcoin ). But, there is one more way that Blockchains secure themselves and that is by being distributed, instead of using a central entity to manage chain, Blockchains use a peer 2 peer network and everyone is allowed to join, when someone joins the network he gets a full copy of the blockchain, the node can use this to verify that everything is still in order.
Now let’s see what happens if a new block should be added to the blockchain. That block will be sent to everyone in the network, each node then verifies the block to make sure the block is all the same and not changed before, and if everything checks out, each node adds that block to the blockchain. All the nodes in the network create consensus, they all agree about what blocks are valid and which aren’t. Blocks with issues will be rejected by other nodes in the network, so to successfully change a block in a blockchain you need to change all the blocks in the chain, redo the proof of work for each block and take control of more than 50 percent of the node in the peer to peer network, only then the changed block will get accepted by any others in the network, so how we can see this is almost impossible to do.
As we can see, Blockchain is a secure technology which is being used by cryptocurrencies. Not only cryptocurrencies but other programs can be hosted on Blockchains to make a better peer to peer network. We at monvid are building a new decentralized and distributed community for streaming platforms based on Blockchains, which allows everyone to stream their own videos, share other videos on the P2P network without any restriction and any advertisements. More information about monvid Streaming Platform will follow in next days. Stay connected with us.
