Blockchain
What is Blockchain ?
Blockchain is Immutable distributed ledger. That enables peer to peer transfer of digital currency or data, without intermediary. This technology has been developed to support Bitcoin by Satoshi Nakamoto.
What is so special ?
This technology enables to build autonomous decentralized applications, by establishing the trust between unknown peers or nodes.
Wait, what is decentralization?
Centralized systems are currently the most widespread model for software applications. Centralized systems directly control the operation of the individual units and flow of information from a single center. All peers nodes are dummies/powerless and dependent on the server to send and receive information. All the popular apps (Google, Facebook, Microsoft ..) are built on centralized architecture model. This model has a inherent problem of single point failure (when server node fails other nodes are in trouble). One important and critical aspect - TRUST, is very feeble in this model as everyone's personal data/information (PII) is owned and managed by the server; As we have noticed data get soled without the individual acceptance and permission, beach of privacy laws.
On the other hand in Distributed systems (Hadoop,Bigdata), computation is spread across multiple nodes, which speeds up the computing time. This architecture has built in master and slave mechanism where instructions will only come from master. That way a system can be both centralized and distributed. Most of the World Wide Web (WWW) is either centralized or distributed.
In Decentralized architecture nodes are independent and they have their own instruction set, thus no central point failure is possible. One of the famous decentralized is application BitTorrent. It is built on the BitTorrent protocol to heavily cut down the download time of huge media files. In BitTorrent there is no central servers, the users who install the BitTorrent app for upload/download will join as peer nodes into the network. For example you started downloading a movie using BitTorrent app, It downloads the parts of the movie from different sources in same time and merges it. If the movie is very popular it has many sources to download it and subsequently uploading it.
What are the problems in implementing the decentralization applications?
The main problem is Byzantine Generals Problem. Anybody could make up their own trackers to replace true files with bogus things, but hashes provide some form of protection against this. The most common attack is after downloading a file with BitTorrent, we are put on a spot as it links to an evil website to download some software or a virus to steel our personal data or hijack your OS/Data. this is called poisoning. BitTorrent is vulnerable for these kind of attacks. This problems arises because of the lack of coordination among the distributed nodes and no trust mechanism is established between the nodes of the network.
Blockchain solves this problem with the help of Proof-Of-Work algorithm, by establishing the trust and to come up with consensus that is resistant to attackers trying to undermine it.
In my coming article i will try to articulate how the Blockchain solves the problem, with more details ...
