cryptocurrency Blockchains exchange are incredibly popular nowadays.
what is a blockchain?
How do they work, what problems do they solve and how can they be used? Like the name indicates, a blockchain is a chain of blocks that contains information. This technique was originally described in 1991 by a group of researchers and was originally intended to timestamp digital documents sot hat it’s not possible to backdate them or to tamper with them. Almost like a notary. However it went by mostly unused until it was adapted by Satoshi Nakamoto in 2009 to create the digital cryptocurrency exchange Bitcoin news. A btc blockchain is a distributed ledger that is completely open to anyone. They have an interesting property: once some data has been recorded inside a cryptocurrency Blockchains exchange, it becomes very difficult to change it.
how does that work?
Well, let’s take a closer look at a block. Each block contains some data, the hash of the block and the hash of the previous block. The data that is stored inside a block depends on the type of blockchain. The Bitcoin blockchain for example stores the details about a transaction in here, such as the sender, receiver and amount of coins. A block also has a hash. You can compare a hash to a fingerprint. It identifies a block and all of its content sand it’s always unique, just as a fingerprint. Once a block is created, it’s hash is being calculated. Changing something inside the block will cause the hash to change.
in other words cryptocurrency exchange:
hashes are very useful when you want to detect changes to blocks. If the fingerprint of a block changes, it no longer is the same block. The third element inside each block is the hash of the previous block. This effectively creates a chain of block sand it’s this technique that makes a coinmarketcap blockchain or cryptocurrency exchange so secure. Let’s take an example. Here we have a chain of 3 blocks. As you can see, each block has a hash and the hash of the previous block.
So block no three ranks to block no two and no two ranks to no first. Now the 1st block is a bit special, it can not point to previous blocks because it’s the first one. We call this the genesis block. Now let’s say that you tamper with the second block. This causes the hash of the block to change as well. In turn that will make block 3 and all following blocks invalid because they no longer store a valid hash of the previous block.
So changing a single block will make all following blocks invalid. But using hashes is not enough to prevent tampering. Computers these days are very fast and can calculate hundreds of thousands of hashes per second. You could effectively tamper with a block and recalculate all the hashes of other blocks to make your blockchain valid again.
So to mitigate this, blockchains have something called proof-of-work. It’s a mechanism that slows down the creation of fresh blocks.
In cryptocurrency exchange Bitcoins case:
it takes regarding Ten+ minutes to compute bitcoin price the need proof-of-work as well as included a fresh block to the chain. This system makes it very hard to tamper with the blocks, because if you tamper with 1 block, you’ll need to recalculate the proof-of-work for all the following blocks.
So the dependability of a blockchain or cryptocurrency exchange approach from its making use of hashing as well as the big proof-of-work system. But there is one more way that blockchains secure themselves as well as that’s by being distributed. Instead of using a central entity to manage the chain, block-chains use a peer-to-peer network and anyone is allowed to join. When someone joins this network, he gets the full copy of the block-chain. The node can use this to verify that everything is still in order.
Now let’s see what happens when someone creates a new block. That fresh block is send to everyone on the network. Each node then verifies the block to make sure that it hasn’t been tampered with. If everything checks out, each node adds this block to their own blockchain & cryptocurrency exchange. All the nodes in this network create consensus. They agree about what blocks are valid and which aren’t. Blocks that are tampered with will be rejected by other nodes in the network.
So to successfully tamper with a block chain you’ll need to tamper with all blocks on the chain, redo the proof-of-work for each block and take control of more than 50% of the peer-to-peer network. Only then will your tampered block become accepted by everyone else. This is almost impossible to do!
Blockchains are also constantly evolving. One of the more recent developments is the creation of smart contracts. These Bloomberg futures contracts are simple programs that are stored on the blockchain and can be used to automatically exchange coins based on certain conditions. More on smart contracts in a later video. The creation of blockchain with cryptocurrency exchange technology peaked lot of people’s interest. Soon, others realized that the technology could be used for other things like storing medical records, creating a digital notary or even collecting taxes.
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