CryptoVarna

Shared, trusted, public ledger of transactions, that everyone can inspect but which no single user controls. It is a cryptographed, secure, tamper-resistant distributed database. It solves a complex mathematical problem to exist. A blockchain is a perfect place to store value, identities, agreements, property rights, credentials, etc. Once you put something like a Bitcoin into it, it will stay there forever. It is decentralized, disintermediated, cheap and censorship-resistant. Read an article here.  Applications of Blockchain: Bitcoin (cryptocurrency), Namecoin (wants to replace the entire DNS system of the Internet), or Sia (a decentralized cloud storage), Ethereum (Turing complete Virtual Machine where you can run any smart contract); Any centralized service like eBay, Dropbox can potentially be built in a decentralized way using blockchain technology, considerably lowering transaction costs

A cryptocurrency is a digital or virtual currency designed to work as a medium of exchange. It uses cryptography to secure and verify transactions as well as to control the creation of new units of a particular cryptocurrency. Essentially, cryptocurrencies are limited entries in a database that no one can change unless specific conditions are fulfilled

Bitcoin is a cryptocurrency that runs on a global peer to peer network, is decentralised (no single entity can control it), it’s open source (wallet & transaction verification), bypassing middlemen or central authority, with no issuer or acquirer, anyone with a computer or smartphone can use it.

Ethereum is an open software platform based on blockchain technology that enables developers to write smart contracts and build and deploy decentralized applications(Dapps). The native token of the blockchain is called Ether which is used to pay for transaction fees, miner rewards and other services on the network. The main innovation of Ethereum is the Ethereum Virtual Machine (EVM) which runs on the Ethereum network and enables anyone to run any application. The EVM makes the process of developing blockchain applications much easier. Before the emergence of Ethereum developers had to develop a dedicated blockchain for each application they wanted to create. This process is time-consuming and resource-intensive. Ethereum will enable the development of many applications on the same platform, making the process much easier and accessible for developers. The Ethereum Project, based in Switzerland, raised millions in seed money by pre-mining and selling ethers to supporters & investors. As opposed to Bitcoin, its scripting language is Turing-complete and full-featured, expanding the kinds of smart contracts that it can support. The Ethereum project wants to “decentralize the web” by introducing four components as part of its roadmap: static content publication, dynamic messages, trustless transactions and an integrated user-interface

For an application to be considered a Dapp or decentralized application it must meet the following criteria (1) Application must be completely open-source, it must operate autonomously, and with no entity controlling the majority of its tokens. The application may adapt its protocol in response to proposed improvements and market feedback, but all changes must be decided by consensus of its users. (2) Application data and records of operation must be cryptographically stored in a public, decentralized blockchain in order to avoid any central points of failure. (3) The application must use a cryptographic token (bitcoin or a token native to its system) which is necessary for access to the application, and any contribution of value from miners/farmers should be rewarded with the application’s tokens. (4) The application must generate tokens according to a standard cryptographic algorithm acting as a proof of the value nodes are contributing to the application (Bitcoin uses the Proof of Work Algorithm)

ICOs are types of crowdfunding mechanisms conducted on the blockchain. Originally, the main idea of an ICO was to fund new projects by pre-selling coins/tokens to investors interested in the project. Entrepreneurs present a whitepaper describing the business model and the technical specifications of a project before the ICO. They lay out a timeline for the project and set a target budget where they describe the future funds spending (marketing, R&D, etc.) as well as coin distribution (how many coins are they going to keep for themselves, token supply, etc.). During the crowdfunding campaign, investors purchase tokens with already established cryptocurrencies like Bitcoin and Ethereum.