Nano (cryptocurrency)

Nano is a peer-to-peer, decentralized, and open-source cryptocurrency. The currency is based on directed acyclic graph data structure and distributed ledger, making it possible for Nano to work without intermediaries. To agree on what transactions to commit, or forming consensuses, it uses a system called "Open Representative Voting" with weight based on the amount of currency they hold.

Nano was launched in October 2015 by Colin LeMahieu to address Bitcoin scalability problem. Solving the problem means that transaction fees and confirmation time under load can be decreased. The currency implements no-fee transactions and achieves confirmation in under one second.

History
Colin LeMahieu started development of Nano in 2014 under its original name "RaiBlocks". A year later, RaiBlocks was distributed for free through a captcha-secured faucet. In 2017, after 126,248,289 RaiBlocks were distributed, the faucet shut down. This fixed the total supply to 133,248,297 RaiBlocks, after an addition of a 7,000,000 RaiBlocks developer fund. RaiBlocks rebranded to "Nano" a few years later, on 31 January 2018.

A month later, on 9 February 2018, Italian cryptocurrency exchange BitGrail announced its hack and eventual shutdown. User was prevented from accessing assets stored on the platform, which was collectively worthed 17 million Nano. The victims then launched a class-action lawsuit against BitGrail owner Francesco Firano for recoupment, inside the Florence Courthouse. The exchange was ruled to guilty in January 2019, as it was found to fail at implementing safeguards and reporting losses.

Design
Nano uses a block-lattice data structure, where every account has its own blockchain for storing transactions. It is the first cryptocurrency to use directed acyclic graph data structure, by having a "block" consists of only one transaction and the account's current balance.

Consensus is reached through an algorithm similar to proof of stake named Open Representative Voting. In this system, the voting weight is distributed to accounts based on the amount of Nano they hold; accounts then freely delegate this weight to a peer (node) of their choice. No mining of cryptocurrency is needed.

If two contradictory transactions are broadcast to the network, indicating a double spend attempt, nodes will then vote for either the transactions. Afterwards, they broadcast their vote to the other nodes for strictly informational purpose. The first to reach 67% of the total voting weight is confirmed, while the other transaction is discarded.