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|0.000001||µXEM (microXEM) - smallest unit|
|0.001||mXEM (milliXEM) - thousandth unit|
|Date of introduction||2015|
|Genesis Block Production||Fixed 8,999,999,999 XEM total|
Block time 1 minute
NEM is a peer-to-peer cryptocurrency and blockchain platform launched on March 31, 2015. Written in Java, with a C++ version in the works, NEM has a stated goal of a wide distribution model and has introduced new features to blockchain technology such as its proof-of-importance (POI) algorithm, multisignature accounts, encrypted messaging, and an Eigentrust++ reputation system. The NEM blockchain software is used in a commercial blockchain called Mijin, which is being tested by financial institutions and private companies in Japan and internationally.
The NEM developers are pseudonymous. NEM was started by a Bitcoin Talk forum user called UtopianFuture who was inspired by Nxt. The initial plan for NEM was to create a fork of NXT, but this was eventually dismissed in favor of a completely new codebase. Starting on January 19, 2014, an open call for participation began on the Bitcointalk forum. The goal of the call was to create a community-oriented cryptocurrency from the ground up.
In April 2016, Tech Bureau, the operator one of Japan’s largest cryptocurrency exchanges, Zaif, formed a partnership with NEM for a new blockchain engine.
On 26 January 2018, Japanese cryptocurrency exchange Coincheck, was the victim of a massive hack resulting in a loss of 523 million NEM coins, worth approximately $534 million. The hack only involved NEM. Because the security breach was caused by the lack of strong security measures of Coincheck, the NEM development team refused to conduct a hard fork. Instead NEM is creating an automated tagging system. This automated system will follow the money and tag any account that receives tainted money. The result of these actions was that NEM stopped tracking the stolen coins approximately mid-March 2018, after concluding that enough data was provided to the law enforcement authorities. 
Another client was the NEM Community Client (NCC). The NIS is connected to the P2P network and acts as a gateway for the NCC. The NCC is client software that includes a wallet. The NCC has since been deprecated in favor of the NanoWallet. Both NCC and the NanoWallet can be run isolated from the internet, providing security through an airgap.
Although the NEM client is open source and available on GitHub, the NEM server based component, or NIS, is closed source. The pseudonymous developers of Catapult say that the C++ rewrite, Catapult, will be open source.
As of February 2018, maintenance of the open source portions of NEM's core has been sparse. With a short-lived exception of some moderate code revisions made in mid-2016, only minor changes have been made to nem.core on GitHub since late December of 2015 (e.g., comment sections in code, single line additions or changes).
Namespaces on the NEM system are a domain naming system similar to the internet's centralized ICANN domain name system. Within namespaces, there are higher level domains and subdomains. This allows one person with one domain to create many different subdomains for their different projects or outside business accounts. It also helps to build and maintain a reputation system for Mosaics.
NEM employs an Eigentrust++ as a reputation system. NEM ensures the health of the blockchain by monitoring past behavior of nodes within the network. In proof-of-work, the amount of work a node does is used as a measure for its ability to protect the network. But, with Eigentrust++, it is the quality of work that is important. This adds to the NEM network's ability to be run and maintained efficiently.
POI is the algorithm used in NEM to time stamp transactions. A NEM user's importance is determined by how many coins they have and the number of transactions made to and from their wallet. POI uses the NCDawareRank network centrality measure, the topology of the transaction graph, as well as a number of other relevant signals to achieve consensus. POI is different from other initiatives which use a fee-sharing model that does not take into consideration one's overall support of the network. In proof-of-stake systems a person needs to have large numbers of coins to form a block, but in NEM transactions volume and trust become factors. This was designed to encourage users of NEM to not simply hold XEM but instead actively carry out transactions.
To be eligible for entering the importance calculation, an account must have at least 10,000 vested XEM. All accounts owning more than 10,000 vested XEM have a non-zero importance score. With a supply of 8,999,999,999 XEM, the theoretical maximum number of accounts with non-zero importance is 899,999. In practice, the number of actual accounts with non-zero importance is not expected to approach the theoretical max due to inequalities in held XEM and also the temporal costs associated with vesting. If NEM becomes very popular, a threshold of 10,000 vested XEM could be undesirable. If necessary, this number could be updated in the future via a hard fork, which is the same procedure for adjusting transaction fees and other parameters related to harvesting.
Harvesting is the act of forming blocks. A harvester must have at least 10,000 vested XEM in his/her account and be running a booted and synchronized node. Once a block is formed by that harvester, a new block is added to the chain and all the fees collected from that block will be delivered to the harvester’s account.
NEM also has a feature called delegated harvesting which allows people to request others to form blocks and process fees for them, but done in a safe and secure way so that a person’s funds are not ever locked up, and fees are always given directly to the person that activated delegated harvesting, not the person that was harvesting for them.
Messages can be included in transactions in either encrypted, unencrypted, or hex messaging forms. No XEM needs to be sent in order for a message to be sent on the XEM network. This can be used for secure communication to any XEM address, as well as blockchain based applications. The fee for sending unencrypted messages is currently 1 XEM for every 32 characters, while encrypted messages will vary.
NEM implements multisig (short for multi-signature) technology on its platform. Specifically, NEM implements m of n multisignature, where m ≤ n. This means that m out of a total of n signatories must sign a transaction before it can be broadcast onto the blockchain. NEM's multisignature works by making a contract on chain so that the "m" accounts have full transaction privileges over the account that has been turned into a multisig account. Since the contract metadata is on chain, it can easily be updated by adding or subtracting additional signers given that the required number of parties agree on it.
Multisignature accounts require that another user or users sign a transaction before it can be broadcast onto the blockchain. This means that if one person loses their wallet through a hack, no money can be spent unless another wallet (or wallets if m is more than 2) signs it. Multisignature accounts also help protect community-held funds, in that a majority of designated users must agree before a transaction can be spent from a community-held wallet. This is especially important considering over a third of all XEM in circulation is held in these community wallets.
Mijin is a private blockchain that uses the NEM software. The developers claim that it will reduce banking institutional costs by 90% while making banking more secure. Sakura Internet is partnered with Tech Bureau to offer 6 month free trials of Mijin for people to try. It was tested in December 2015 by Japan's largest trust bank, SBI Sumishin Net Bank, owned by Sumitomo Mitsui Trust Holdings, to add to their online banking services.
Built on NEM, Choice is a payments provider in New Zealand that reduces and redistributes transaction fees for businesses.The founders hope to use the platform to put New Zealanders interest first and give back the majority of their earnings to charity. In 2018 they were accepted into the Kiwibank Fintech Accelerator program and also raised NZ$1 million capital in the form of non-equity funding from NEM.IO foundation.