The following features make the revolutionary technology of blockchain stand out:
Blockchains are decentralized in nature meaning that no single person or group holds the authority of the overall network. While everybody in the network has the copy of the distributed ledger with them, no one can modify it on his or her own. This unique feature of blockchain allows transparency and security while giving power to the users.
With the use of Blockchain, the interaction between two parties through a peer-to-peer model is easily accomplished without the requirement of any third party. Blockchain uses P2P protocol which allows all the network participants to hold an identical copy of transactions, enabling approval through a machine consensus. For example, if you wish to make any transaction from one part of the world to another, you can do that with blockchain all by yourself within a few seconds. Moreover, any interruptions or extra charges will not be deducted in the transfer.
The immutability property of a blockchain refers to the fact that any data once written on the blockchain cannot be changed. To understand immutability, consider sending email as an example. Once you send an email to a bunch of people, you cannot take it back. In order to find a way around, you’ll have to ask all the recipients to delete your email which is pretty tedious. This is how immutability works.
Once the data has been processed, it cannot be altered or changed. In case of the blockchain, if you try to change the data of one block, you’ll have to change the entire blockchain following it as each block stores the hash of its preceding block. Change in one hash will lead to change in all the following hashes. It is extremely complicated for someone to change all the hashes as it requires a lot of computational power to do so. Hence, the data stored in a blockchain is non-susceptible to alterations or hacker attacks due to immutability.
With the property of immutability embedded in blockchains, it becomes easier to detect tampering of any data. Blockchains are considered tamper-proof as any change in even one single block can be detected and addressed smoothly. There are two key ways of detecting tampering namely, hashes and blocks.
As described earlier, each hash function associated with a block is unique. You can consider it like a fingerprint of a block. Any change in the data will lead to a change in the hash function. Since the hash function of one block is linked to next block, in order for a hacker to make any changes, he/she will have to change hashes of all the blocks after that block which is quite difficult to do.
Types of Blockchains
Though Blockchain has evolved to many levels since inception, there are two broad categories in which blockchains can be classified majorly i.e. Public and Private blockchains.
Before heading towards the difference between these two, let’s keep a check on the similarities that both public and private blockchain have:
- Both Public and Private blockchain have peer-to-peer decentralized networks.
- All the participants of the network maintain the copy of the shared ledger with them.
- The network maintains copies of the ledger and synchronizes the latest update with the help of consensus.
- The rules for immutability and safety of the ledger are decided and applied on the network so as to avoid malicious attacks.
Now that we know the similar elements of both these blockchains, let’s learn about each of them in detail and the differences between them.
Public Blockchain – As the name suggests, a public blockchain is a permissionless ledger and can be accessed by any and everyone. Anyone with the access to the internet is eligible to download and access it. Moreover, one can also check the overall history of the blockchain along with making any transactions through it. Public blockchains usually reward their network participants for performing the mining process and maintaining the immutability of the ledger. An example of the public blockchain is the Bitcoin Blockchain.
Public blockchains allow the communities worldwide to exchange information openly and securely. However, an obvious disadvantage of this type of blockchain is that it can be compromised if the rules around it are not executed strictly. Moreover, the rules decided and applied initially have very little scope of modification in the later stages.
Private Blockchain – Contrary to the public blockchain, private blockchains are the ones which are shared only among the trusted participants. The overall control of the network is in the hands of the owners. Moreover, the rules of a private blockchain can be changed according to different levels of permissions, exposure, number of members, authorization etc.
Private blockchains can run independently or can be integrated with other blockchains too. These are usually used by enterprises and organizations. Therefore, the level of trust required amongst the participants is higher in private blockchains.