A blockchain that can be accessed by anyone.
A public blockchain is a decentralized
platform accessible by anyone. In other words, it is permissionless, meaning anyone can join, write and read the information on the platform. A blockchain
is a distributed ledger
where transaction data is packaged and stored in the form of blocks
Therefore, a combination of these “blocks” forms a blockchain. A key factor that differentiates one block from the other is the timestamp
. Once validated, data stored on the platform can’t be altered despite being publicly available.
A public blockchain uses a consensus mechanism to validate transactions. The leading two public blockchains, Bitcoin and Ethereum
, use the proof-of-work (PoW)
consensus mechanism. However, Ethereum has started the journey to transition into a proof-of-stake
(PoS) consensus mechanism.
A public blockchain offers greater transparency compared to private networks
, and is more decentralized since anyone can join and no single entity has control over the whole system. Unfortunately, a lot of public blockchains also suffer from low transaction speeds and other scalability issues. Furthermore, a public blockchain is also limited to a few consensus mechanisms compared to a private blockchain.
A private and public blockchain are similar in the sense that each node
on their network has an exact copy of their ledger
, their stored data is immutable
and both platforms rely on transaction validators