Satoshi Nakamoto, the creator(s) of Bitcoin, had a vision for the crypto-currencies. It was, "A purely peer-to-peer version of electronic cash that would allow online payments to be sent directly from one party to another without going through a financial institution." The Peer-to-peer model helps in decentralisation and several consensus algorithm exists that can be used by a blockchain to help reach an agreement for any transaction. Surely lots of cryptocurrencies exist that are decentralized and have a great trust model, but there are some other considerations too if they need to compete with the FIAT:

First, the transaction fees should be minimal. It doesn't make sense to use the crypto as an alternative to regular money if the fees to transfer it is very high. Consider paying at a local grocery store with Ethereum (on-chain) for buying milk. 

Second, the transaction should be confirmed as fast as possible. On a blockchain, a transaction is confirmed only when certain number of new blocks are added on top of it. Bitcoin transaction usually needs 6 block confirmation. Average block time is around 10 minutes. So, it may take up to 60 minutes for you to leave with milk you bought with bitcoin from the grocery store. Oh and in case of Ethereum, which has average block time of 15 seconds, things get a little complex. 7 confirmations is assumed to be sufficient according to the Ethereum white paper. But depending on the amount of fees you pay, your transaction may get processed early (if you pay more fees ) or it may get delayed (if you pay less fees). This is because higher gas fees transaction will be selected first by miners and approval time will be shorter.

And the energy consumed should be kept as minimal as possible. Depending on the consensus algorithm (POS, POW), the amount of energy consumed per transaction changes considerably. It does not makes sense to waste Kilo-watts of energy just for processing a transaction of a miniscule amount. When millions of miniscule amount transactions are sent over the network, it will become rather inefficient. So, this also needs to be dealt with. 

To be fair, Ethereum was not developed to be an alternative to FIAT. It was built to empower Decentralised Apps. And with the use of Smart Contracts, Ethereum has been on top of its league. The blockchain I am going to talk about is meant to be used as an alternative to currency. It is not just there as a store of value. Something very close to what Satoshi envisioned. A decentralized ecosystem which, in future, will be used by ordinary person to buy/sell goods.

Introducing Nano, it is a digital currency with ZERO FEES. The transactions are almost instantaneous. It is Eco-Friendly as it not mineable and requires very small amount of energy. Nano achieves this by using blockchain in slightly different way than many other digital currencies. Usually a single block-chain is maintained on which new blocks, containing transactions, are added. Nano uses a block-lattice structure. Essentially, each user on Nano network has their own blockchain on which only they can write.

How does it work?
As soon as you create a transaction, your own block-chain is updated instantaneously. This means that you simply decrease the balance in your account and include destination address in the transaction. Now, to publish this transaction over on the main blockchain, each user chooses his/her representative. After a small amount of POW, the user account will send the transaction to its representative who will publish the transaction on the main blockchain and thus, updates the ledger. The created transaction remains in a pending state until the receiver receives the transaction. The sender has sent the amount and so their next transaction will increase or decrease on the balance in their latest state. It does not matter to the sender when the receiver gets online to receive fund. According to the sender perspective, they have send the funds.

The receiver of the token can simply update their own blockchain when they see the updated balance on the main ledger. They do this by adding a new transaction where they increase their account balance with the amount they received. The transaction also contains the Hash of the sender's transaction which is publicly viewable on the main ledger. So, there is need to stay online for an ordinary user. They can add the new transaction at a later point of time. Only the Representative nodes are required to be online. Once they receives the amount transferred to them  by adding the correspoding transaction in their block-chain, sender's pending-state block is converted to Confirmed.

The Principal representatives vote on who gets to publish the next block. See, this is where the efficiency of NANO lies. The nodes are not fighting to publish a new block. This is because there is no reward for doing it. Instead, they are doing this to keep the network up and the main blockchain synchronized with the user's blockchain. Essentially like a non-mining Full node on bitcoin, they check whether all the details in the transactions line up correctly.

It depends completely on the user who they chose to be their representative. There is no incentive in being the Principal Representative. Each Principal Representative has voting weight associated with it which depends on how much of the total NANO is being represented by it. To become a PR, the account needs to have atleast 0.1% of the Voting weight delegated to it.

How Double-Spend attacks are avoided?
Whenever there is a double-spend, an election is triggered. Each Principal Representive will cast a vote for the transaction they saw first. The transaction with most vote will be added and the other(s) discarded.

How Spam Attacks are avoided?
Noticed the small amount of POW required by an account to send a transaction? Well that miniscule amount adds up if someone tries to send lots and lots of transactions simultaneously.

51% attack?
It will not be financially great for the attacker. Because 51% attack requires an attacker to have either:
1. 51% of the Nano delegated through him. However, if users find out that their representative is malicious, they are free to change their representative.
2. The other case is that the attacker own 51% of all NANO tokens. If this happens, then the users lose their trust in blockchain which will lead to the users leaving the ecosystem (similar to other blockchain). This is not good for the attacker because the currency will have no value if no one uses it. So, their 51% NANO will have no value. Not good!

NANO is crypto-currency which does what is promises and does it well. It offers zero transaction fees. So if you transfer say 0.01 NANO to me :-), I will receive 0.01 NANO. I can then send the 0.01 NANO back to you and you will receive the same amount. We can repeat the process as long as you like. Another good thing is that, the transaction takes less than a second to complete. In short, it is one of the greatest blockchain technology which aims to stay true to Satoshi vision of digital currency. When, and if, crypto ever has mass-adoption, I would really be surprised if NANO is not the one of the coin that will lead the pack.

There are various open source wallets for holding NANO. Just to see how fast NANO is, head over to this site to download one of the NANO wallet named Natrium. Create a NANO account for yourself (Securely store the SEED PHRASE). 
Head over to Nano Faucet and Input your public NANO address. It will not even take a second for the fund to reach your wallet. Also, the faucet sends 0.000012 NANO as of writing this article. And you will receive 100% of it. No fees whatsoever. See, DO LESS BUT DO IT BETTER THAN ANYONE ELSE.

DYOR before investing. Until next time.