Cryptocurrencies are digital currencies that are secured using cryptography. A lot of people do not realize that there are 2 types of cryptocurrencies. They are both very similar, but there is one main difference between them. There is one main cryptocurrency Bitcoin and all other cryptocurrencies are altcoins and tokens.
Those altcoins are simply alternative cryptocurrencies to Bitcoin and majority of those altcoins are a variant (fork) of Bitcoin, built using Bitcoin open-sourced original protocol with changes to its underlying codes and therefore conceiving an entirely new coin with a different set of features. Examples of these kinds of coins are Litecoin, Dogecoin or Namecoin.
Tokens on the other side are a representation of a certain asset or utility, that usually resides on top of another blockchain. Tokens can represent basically any assets that are fungible and tradeable, from commodities to loyalty points to even and mainly other cryptocurrencies. Creating token is a much easier process as you do not have to modify the codes from a certain protocol or create a blockchain from scratch. All you have to do is follow a standard template on the blockchain, for instance on Ethereum platform which allows you to create your own tokens.
This functionality of creating your own tokens is made possible through the use of smart contracts; programmable computer codes that are self-executing and do not need any third-parties to operate. Examples of some tokens are Aeternity, Aion or Basic Attention Token (BAT). However, there are some cryptocurrencies that are centralized, but most of them are decentralized. Most of the coins are independent, decentralized and they work without anyone´s control such as Bitcoin, Litecoin or Ethereum.
However, there are some centralized systems which are not even cryptocurrencies such as Ripple. Ripple is a cross-border payment solution for large financial institutions based on blockchain technology. Where international payment may take a few days to make with a very high cost, there comes Ripple with transactions settled in four seconds and with no fees. So, the advantage of Ripple is that it is fast and low-cost, but it is a tool for banks and big institutions, meaning it is controlled and this market is not so free as other cryptocurrencies.
source: https://www.cnbc.com/2017/12/14/bitcoin-ether-litecoin-ripple-differences-between-cryptocurrencies.html
