On June 2, 2018, at 10:43 pm EDT, ZenCash (ZEN) suffered from a 51% attack according to a release issued on the ZenCash blog. The team also issued a tweet about the hack. A total of $550,000 was lost in double spent transactions due to the attack at current price estimates.
A 51% attack occurs when hackers control more than 51% of the hashing power of the network. Since the miners are now a 51% majority, they can attempt to manipulate the blockchain. However, success is not guaranteed. Recent transactions will be easier to modify compared to older transactions, and new coins cannot be created. Such attacks are more difficult to achieve with larger cryptocurrencies as more resources are needed. This attack is estimated to have cost the hacker $30,000.
In this attack, which lasted four hours, the hacker double spent two large transactions (13,000 and 6,600 ZEN) on blocks 318204 and 318234. Mining pool operators notified the core development team, and they were quick to mitigate the hack and take preventative measures as well as notify the public of the issues at hand. Exchanges were warned immediately.
The suspect exchange deposit address is zneDDN3aNebJUnAJ9DoQFys7ZuCKBNRQ115. The required number of confirmations has now been increased to 100, which will render more attacks extremely unlikely. The ZenCash team is investigating the matter, and to its credit, the response has been swift and public. The team has also advised users to store funds in a hardware wallet like the Ledger Nano S or, alternatively, a paper wallet.
Launched in May 2017, ZenCash is a fork of ZClassic. It is a privacy-based coin aimed at being censorship resistant with 21 million coins in circulation and no pre-mine or ICO. It runs off the equihash algorithm and is marketed as a “most resilient” and “most secure” system featuring node-to-node encryption across 11,000 Zen secure nodes according to its official page. It is particularly damaging for a privacy and security-based coin to suffer from this type of attack, but ZenCash arguably has too much support and development underway to be permanently affected.
Digital Nomad with an interest in Zen and Blockchain technology.
Law graduate with 3 years experience as a consultant in the capital markets industry and 4 years experience freelancing on UpWork as a Creative Writer.