[what is cryptocurrency?]

Teaching today.
what is cryptocurrency? it is a digital currency in which encryption techniques are used to regulate the generation of units of currency and verify the transfer of funds, operating independently of a central bank.

what this basically mean is that your current currency is issued by the central bank is like manage through a networks or banks therefore they are verifying it on every level, where as a crypto cryptocurrency is not operate or manage by a central bank and it is highly encrypted so no one can just hack in and see the data if you want xyz or if you not, so it is really safe.

Bitcoin was the first cryptocurrency developed in 2009.

since then many new cryptocurrencies are formed and are knows as Altcoin.
Cryptocurrencies are based on De Centralization, which means they are not like operated by one know entity or one know controller De Centralization, they are available in so many networks of computers therefore is really hard to get data or to hack in to steal those funds
 
What is centralized Currencies and Decentralized cryptocurrency
in centralized banking and economic systems such as the federal reserve system, governments control the supply of currency by printing paper money.
that is were you see governments saying interest rate will increase they will be issuing more paper money and all that stuff if your country is good it currency rises other wise it currency fall and that is what you are seeing around the world today example is  Nigeria it currency going down down down because they are operating more and more of money each and everyday, so you are in a fix because the government know how much money they want, they can task you and they can print more money which which will increase the value of your money this is what a centralized banking and economic systems is.
  
Therefore in case of decentralized cryptocurrency, companies or governments can not produce new units. therefore its not under any government control.
This is what is cryptocurrency.
Hope i explained it clearly for your understanding now.