Bitcoin is a decentralized cryptocurrency originally described in a 2008 whitepaper by a person, or group of people, using the alias Satoshi Nakamoto. It was launched soon after, in January 2009. Bitcoin is a peer-to-peer online currency, meaning that all transactions happen directly between equal, independent network participants, without the need for any intermediary to permit or facilitate them. Bitcoin was created, according to Nakamoto’s own words, to allow “online payments to be sent directly from one party to another without going through a financial institution.” Some concepts for a similar type of a decentralized electronic currency precede BTC, but Bitcoin holds the distinction of being the first-ever cryptocurrency to come into actual use.

Ethereum is a decentralized open-source blockchain system that features its own cryptocurrency, Ether. ETH works as a platform for numerous other cryptocurrencies, as well as for the execution of decentralized smart contracts. Ethereum was first described in a 2013 whitepaper by Vitalik Buterin. Buterin, along with other co-founders, secured funding for the project in an online public crowd sale in the summer of 2014 and officially launched the blockchain on July 30, 2015. Ethereum’s own purported goal is to become a global platform for decentralized applications, allowing users from all over the world to write and run software that is resistant to censorship, downtime and fraud.

USDT is a stablecoin (stable-value cryptocurrency) that mirrors the price of the U.S. dollar, issued by a Hong Kong-based company Tether. The token’s peg to the USD is achieved via maintaining a sum of dollars in reserves that is equal to the number of USDT in circulation. Originally launched in July 2014 as Realcoin, a second-layer cryptocurrency token built on top of Bitcoin’s blockchain through the use of the Omni platform, it was later renamed to USTether, and then, finally, to USDT. In addition to Bitcoin’s, USDT was later updated to work on the Ethereum, EOS, Tron, Algorand, and OMG blockchains. The stated purpose of USDT is to combine the unrestricted nature of cryptocurrencies — which can be sent between users without a trusted third-party intermediary — with the stable value of the US dollar.

Polkadot is an open-source sharding multichain protocol that facilitates the cross-chain transfer of any data or asset types, not just tokens, thereby making a wide range of blockchains interoperable with each other. This interoperability seeks to establish a fully decentralized and private web, controlled by its users, and simplify the creation of new applications, institutions and services. The Polkadot protocol connects public and private chains, permissionless networks, oracles and future technologies, allowing these independent blockchains to trustlessly share information and transactions through the Polkadot relay chain (explained further down). Polkadot’s native DOT token serves three clear purposes: providing network governance and operations, and creating parachains (parallel chains) by bonding.

To begin with, it’s important to understand the difference between XRP, Ripple and RippleNet. XRP is the currency that runs on a digital payment platform called RippleNet, which is on top of a distributed ledger database called XRP Ledger. While RippleNet is run by a company called Ripple, the XRP Ledger is open-source and is not based on blockchain, but rather the previously mentioned distributed ledger database. The RippleNet payment platform is a real-time gross settlement (RTGS) system that aims to enable instant monetary transactions globally. While XRP is the cryptocurrency native to the XRP Ledger, you can actually use any currency to transact on the platform. While the idea behind the Ripple payment platform was first voiced in 2004 by Ryan Fugger, it wasn’t until Jed McCaleb and Chris Larson took over the project in 2012 that Ripple began to be built (at the time, it was also called OpenCoin).