Nano, formerly known as Railblocks, is a cryptocurrency that is focused on enabling fast transactions with no fees. Nano's innovative blockchain architecture utilizes a block lattice structure that does not need miners to confirm transactions.
Nano uses a Delegated Proof-of-Stake consensus.

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BitcoinDark is a fork of Bitcoin with a poorly defined purpose and use case. BitcoinDark is based on the InstantDEX protocol, a decentralized exchange for BitcoinDark and other cryptocurrencies supported by the project. The platform is also supposed to include a Pegged Asset Exchange (PAX) to allow users to buy and sell pegged assets – including fiat currencies, commodities, ETFs, and stocks.
BitcoinDark is a Proof-of-Stake (PoS) currency that has gained a significant market cap, but the project has failed to show how its vision will be implemented or how it will add value compared to other blockchain projects.