Bran Cohen, best known as author of the peer-to-peer (P2P) BitTorrent protocol, has responded to some of Vitalik Buterin’s opinions about the state of technology around cryptocurrencies.

On Nov. 25, Cohen, also the current CEO of the Chia network, explained in a Twitter thread why he considers many of Vitalik’s opinions in his Nov. 22 blog post addressing the so-called “hard problems in cryptocurrency,” to be “wrong-headed.”

Sharding is not the only option

Cohen started out by taking a few stabs at Vitalik’s views on sharding and blockchain scalability, where the Ethereum co-founder points out that fully sharded blockchains still have not been seen in action, besides the partially sharded Zilliqa, which recently started running.

Sharding is not the only option to solve blockchain scalability, Cohen wrote. He points to payment channel networks, which according to him, are much “more appealing” and are becoming “a real thing.” He adds:

“What Ethereum's proposing for sharding further breaks this by essentially requiring miners to have all the shards, which is... not sharding, it's just further redefining 'full node' to mean less than it did before.”

ASIC-resistant proof of work

Ethereum settled on its ASIC-resistant proof of work (PoW) algorithm Ethash in early 2015, which according to Vitalik has proven remarkably successful at resisting ASIC. However, Vitalik’s view on ASIC-resistant PoW is that there is a growing consensus that ASIC-resistant algorithms have a limited lifespan, and that ASIC resistance has downsides as they make 51% attacks cheaper.

Cohen seems to agree and calls ASIC-resistant PoW both a pipe dream and a bad idea. Cohen claims that it is a much better idea to be ASIC-friendly, because “ASIC resistance just creates more centralization around manufacture when it inevitably fails.”

Eco-friendly crypto mining

In July, Bram Cohen’s San Francisco-based tech firm Chia Network released a green paper that describes an eco-friendly means of mining cryptocurrencies. Specifically, Chia proposed farming rather than mining to verify blockchains that issue cryptocurrencies, wherein proof-of-space and proof-of-time take the place of the proof-of-work (PoW) principle used to mine Bitcoin (BTC) and Ethereum (ETH). The paper explained: