Website crypto51.app has drawn up a collection of coins and calculated the theoretical cost of a 51% attack on each network. The approximations are based on the cost of an attack over the course of one hour.

A 51% attack is the term used to describe an attack by a miner or group of miners that seize control of over 50% of the blockchains processing power. In a proof-of-work (PoW) blockchain, nodes will assume the blockchain with the most hashing power is the correct version. This gives the attacker the ability to ‘double-spend’ the cryptocurrency – essentially creating coins from thin air.

Reddit user xur17 announced his creation of the website on Reddit yesterday.

The site makes use of hashing power data from the website ‘Mine The Coin‘, which provides coin stats, profit calculations, estimated earnings and mining data on over 100 coins. It also uses CoinMarketCap for coin prices and Nicehash to calculate the required costs to mount a 51% attack.

The cost of such an attack could be reduced even further during the attack if the attacker created new blocks and gained block rewards. However, this cost reduction is not included in the analysis.

Proof of Stake (PoS) protocols are a potential solution for the 51% attack problem, as are coins built on top of other blockchains, such as the popular ERC20 protocol built on Ethereum and used by VeChain, TRON and EOS.

Bitcoin Private (BTCP), Bitcoin Gold (BTG) and Bytecoin (BCN) were amongst the least secure coins listed and are highly vulnerable to attack. Bitcoin Gold has already been subject to a 51% attack recently that cost it $18 million in losses.

John McAfee’s much-touted favorite, Bitcoin Private, would cost as little as $778 to attack at 51% for over an hour, making the likelihood of such an attack imminent. However, as pointed out Dogecoin creator Jackson Palmer, the inability to short such small currencies and their lack of appearance on many exchanges make it difficult to turn a profit from many of them.

Bytecoin is even easier to attack, at only $557. The coin has been the subject of much controversy lately and the last thing it needs is a 51% attack. The cheapest coin to attack on the list is Einsteinium, at $77.  

While critics may argue that releasing such a list might benefit attackers, it also forces many unsafe cryptocurrencies to reassess their security.

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