Blockchain: Is it a hoax?  105

• In June 2018, a cryptocurrency exchange called Bithumb was hacked.

Hackers stole $31 million worth of XRP coins. The North Korean

hacking group known as the Lazarus group claimed the hacking. It

appears Bithumb exchange promised to pay back its users for any

stolen funds.

• In May 2018, Bitcoin Gold cryptocurrency was stolen. This is one of

the strange hacks whereby exchanges holding the Bitcoin Gold cur-

rency (hard fork of Bitcoin) became victims of a 51% attack, where

hackers managed to gain control of more than 50% of the network’s

computing power. Once they managed to do that, hackers were able

to prevent confirmations allowing them to stop payments between

users and make changes to the network’s blockchain ledger. Once in

control of the Bitcoin Gold ledger, hackers put their Bitcoin Gold onto

exchanges, traded them for other cryptocurrencies and withdrew the

amount after selling the cryptocurrencies.

• In May 2018, a cryptocurrency trading app known as Taylor was

hacked. Taylor went through a successful ICO valued at 1.5 million.

Hackers managed to gain access to the company device and took con-

trol of the password file. Hackers stole all of the Ethereum (about

2,578 ETH) raised in the ICO.

• In April 2018, an Indian cryptocurrency exchange called CoinSecure

was hacked. Hackers stole 438 BTC worth $3.5 million. It appeared

that this incident was an inside job as the suspect was CoinSecure

former Chief Information Officer who was later arrested.

• In February 2018, an Italian cryptocurrency exchange called Bitgrail

was hacked. Hackers stole 17 million NANO coins worth $170 mil-

lion. This incident looked suspicious as people are sceptical as to

whether it was a real hack or a scam.

• In January 2018, a leading Japanese cryptocurrency exchange called

Coincheck was hacked because of an insecure platform. The hackers

managed to spread a virus through email that allowed them to steal

private keys. Coincheck did not use smart contracts or multisigna-

tures and also all coins were stored in the same wallet. Hackers stole

523 million NEM coins worth $533 million at the time of the hack.

The hack was believed to be carried out by North Korean hackers,

and the malware originated from Russian hacking groups. Strangely

and luckily, the exchange is still in business and began to offer full

services again in November 2018.

• In December 2017, the NiceHash cryptocurrency mining marketplace,

which allows miners to rent out their hash rate to others, the payment

system was compromised. Hackers stole the contents of users’ Bitcoin

wallets. About 4,736 BTC were stolen worth about $62 million at

the time of the hack. NiceHash managed to return 60% of the stolen

funds to its users.