What is BlockChain ?
August 31, 2018What is BlockChain
According to hyperledger.org
"A blockchain is a
peer-to-peer distributed ledger forged by consensus, combined with a system for
"smart contracts" and other assistive technologies."
Smart contracts
are simply computer programs that execute predefined actions when certain
conditions within the system are met.
Consensus
refers to a system of ensuring that parties agree to a certain state of the
system as the true state.
Blockchain
is a specific form or subset of distributed ledger technologies, which
constructs a chronological chain of blocks, hence the name 'block-chain'. A block refers to a set of transactions that are
bundled together and added to the chain at the same time. In the Bitcoin
blockchain, the miner nodes bundle unconfirmed and valid transactions into a
block. Each block contains a given number of transactions. In the Bitcoin
network, miners must solve a cryptographic challenge to propose the next block.
This process is known as 'proof of work',
and requires significant computing power. We shall discuss proof of work in
more detail in the Consensus Algorithms
section. For a brief history of blockchain technology, please click here.
Timestamping is another key feature of
blockchain technology. Each block is timestamped, with each new block referring
to the previous block. Combined with cryptographic hashes,
this timestamped chain of blocks provides an immutable record of all
transactions in the network, from the very first (or genesis) block.
A block commonly consists of four pieces
of metadata:
The reference to the previous block
The proof of work, also known as a nonce
The timestamp
The Merkle tree root for the transactions
included in this block.
Distributed Ledger Technology (DLT)
August 30, 2018
Distributed
Ledger Technology (DLT)
A distributed ledger
is a type of data structure which resides across multiple computer devices,
generally spread across locations or regions.
Distributed Ledger Technology
includes blockchain technologies and smart contracts. While distributed ledgers
existed prior to Bitcoin, the Bitcoin blockchain marks the convergence of a
host of technologies, including timestamping of transactions, Peer-to-Peer
(P2P) networks, cryptography, and shared computational power, along with a
new consensus algorithm.
•A data model
that captures the current state of the ledger
•A language of transactions
that changes the ledger state
•A protocol
used to build consensus among participants around which transactions will be
accepted, and in what order, by the ledger.