Monero (;
Abbreviation
An abbreviation (from Latin ''brevis'', meaning ''short'') is a shortened form of a word or phrase, by any method. It may consist of a group of letters or words taken from the full version of the word or phrase; for example, the word ''abbrevia ...
: XMR) is a decentralized
cryptocurrency
A cryptocurrency, crypto-currency, or crypto is a digital currency designed to work as a medium of exchange through a computer network that is not reliant on any central authority, such as a government or bank, to uphold or maintain it. It i ...
. It uses a public
distributed ledger with
privacy-enhancing technologies that obfuscate transactions to achieve anonymity and
fungibility. Observers cannot decipher addresses trading monero, transaction amounts, address balances, or transaction histories.
The protocol is
open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
and based on
CryptoNote, a concept described in a 2013
white paper authored by Nicolas van Saberhagen. The cryptography community used this concept to design Monero, and deployed its mainnet in 2014. Monero uses
ring signatures,
zero-knowledge proofs, "stealth addresses", and
IP address–obscuring methods to obfuscate transaction details. These features are baked into the protocol, though users can optionally share view keys for third-party auditing. Transactions are validated through a
miner
A miner is a person who extracts ore, coal, chalk, clay, or other minerals from the earth through mining. There are two senses in which the term is used. In its narrowest sense, a miner is someone who works at the rock face; cutting, blasting, ...
network running RandomX, a
proof-of-work algorithm . The algorithm issues new coins to miners, and was designed to be resistant to application-specific integrated circuit (
ASIC
An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficien ...
) mining.
Monero has the third-largest developer community among cryptocurrencies, behind
Bitcoin
Bitcoin ( abbreviation: BTC; sign: ₿) is a decentralized digital currency that can be transferred on the peer-to-peer bitcoin network. Bitcoin transactions are verified by network nodes through cryptography and recorded in a public distr ...
and
Ethereum. Its privacy features have attracted
cypherpunks and users desiring privacy measures not provided in other cryptocurrencies. It is increasingly used in illicit activities such as
money laundering
Money laundering is the process of concealing the origin of money, obtained from illicit activities such as drug trafficking, corruption, embezzlement or gambling, by converting it into a legitimate source. It is a crime in many jurisdictions ...
,
darknet market
A darknet market is a commercial website on the dark web that operates via darknets such as Tor or I2P. They function primarily as black markets, selling or brokering transactions involving drugs, cyber-arms, weapons, counterfeit currency, stole ...
s,
ransomware
Ransomware is a type of malware from cryptovirology that threatens to publish the victim's personal data or permanently block access to it unless a ransom is paid off. While some simple ransomware may lock the system without damaging any files, ...
, and
cryptojacking. The United States
Internal Revenue Service
The Internal Revenue Service (IRS) is the revenue service for the United States federal government, which is responsible for collecting U.S. federal taxes and administering the Internal Revenue Code, the main body of the federal statutory ta ...
(IRS) has posted bounties for contractors that can develop monero-tracing technologies.
Background
Monero's roots can be traced back to
CryptoNote, a
cryptocurrency
A cryptocurrency, crypto-currency, or crypto is a digital currency designed to work as a medium of exchange through a computer network that is not reliant on any central authority, such as a government or bank, to uphold or maintain it. It i ...
protocol first described in a
white paper published by Nicolas van Saberhagen (presumed pseudonymous) in October 2013.
The author described privacy and anonymity as "the most important aspects of electronic cash" and called
bitcoin
Bitcoin ( abbreviation: BTC; sign: ₿) is a decentralized digital currency that can be transferred on the peer-to-peer bitcoin network. Bitcoin transactions are verified by network nodes through cryptography and recorded in a public distr ...
's traceability a "critical flaw".
A Bitcointalk forum user "''thankful_for_today''" coded these ideas into a coin they dubbed BitMonero. Other forum users disagreed with ''thankful_for_todays direction for BitMonero, so forked it in 2014 to create monero.
''Monero'' translates to ''coin'' in
Esperanto
Esperanto ( or ) is the world's most widely spoken constructed international auxiliary language. Created by the Warsaw-based ophthalmologist L. L. Zamenhof in 1887, it was intended to be a universal second language for international communi ...
,
and the Esperanto ''moneroj'' is sometimes used for plural. Both van Saberhagen and ''thankful_for_today'' remain anonymous.
Monero has the third-largest community of developers, behind bitcoin and
Ethereum.
The protocol's lead maintainer was previously South African developer Riccardo Spagni.
Much of the core development team chooses to remain anonymous.
Improvements to Monero's protocol and features are, in part, the task of the Monero Research Lab (MRL). The lab is a rotating cast of researchers, scientists, cryptographers, and developers. Similar to the core VC development team, a portion of the MRL chooses to remain anonymous or otherwise work pseudonymously.
Privacy

Monero's key features are those around privacy and anonymity.
Even though it is a public and decentralized ledger, all transaction details are obfuscated.
This contrasts to bitcoin, where all transaction details, user addresses, and wallet balances are public and transparent.
These features have given Monero a loyal following among
crypto anarchists,
cypherpunks, and privacy advocates.
The transaction outputs, or notes, of users sending Monero are obfuscated through
ring signatures, which groups a sender's outputs with other decoy outputs. Encryption of transaction amounts began in 2017 with the implementation of ring confidential transactions (RingCTs).
Developers also implemented a
zero-knowledge proof method, "Bulletproofs", which guarantee a transaction occurred without revealing its value. Monero recipients are protected through "stealth addresses", addresses generated by users to receive funds, but untraceable to an owner by a network observer.
These privacy features are enforced on the network by default,
though users have the option to share a private view key to permit third party auditing of their wallet, or a transaction key to audit a transaction.
Monero uses Dandelion++, a protocol which obscures the
IP address of devices producing transactions. This is done through a method of transaction broadcast propagation; new transactions are initially passed to one node on Monero's peer-to-peer network, and a repeated
probabilistic method is used to determine when the transaction should be sent to just one node or broadcast to many nodes in a process called flooding.
This method was motivated by the growing
blockchain analysis Blockchain analysis is the process of inspecting, identifying, clustering, modeling and visually representing data on a cryptographic distributed-ledger known as a blockchain. The goal of blockchain analysis is to discover useful information about ...
market and the potential use of
botnets for analysis.
Efforts to trace transactions
In April 2017, researchers highlighted three major threats to Monero users' privacy. The first relies on leveraging the ring signature size of zero, and ability to see the output amounts. The second, "Leveraging Output Merging", involves tracking transactions where two outputs belong to the same user, such as when they send funds to themselves ("churning"). Finally, "Temporal Analysis", shows that predicting the right output in a ring signature could potentially be easier than previously thought. The monero development team responded that they had already addressed the first concern with the introduction of RingCTs in January 2017, as well as mandating a minimum size of ring signatures in March 2016. In 2018, researchers presented possible vulnerabilities in a paper titled "An Empirical Analysis of Traceability in the Monero Blockchain".
[Moser, Malte et al. (2018). "An Empirical Analysis of Traceability in the Monero Blockchain". ''Proceedings on Privacy Enhancing Technologies''. 2018 (3): 143. .] The Monero team responded in March 2018.
In September 2020, the United States
Internal Revenue Service
The Internal Revenue Service (IRS) is the revenue service for the United States federal government, which is responsible for collecting U.S. federal taxes and administering the Internal Revenue Code, the main body of the federal statutory ta ...
's
criminal investigation division (IRS-CI), posted a $625,000 bounty for contractors who could develop tools to help trace Monero, other privacy-enhanced cryptocurrencies, the Bitcoin
Lightning Network
The Lightning Network (LN) is a "layer 2" payment protocol layered on top of Bitcoin (and other blockchains and cryptocurrencies). It is intended to enable fast transactions among participating nodes and has been proposed as a solution to the ...
, or other "layer 2" protocols.
[Franceschi-Bicchierai, Lorenzo (2020-09-12).]
The IRS Wants to Buy Tools to Trace Privacy-Focused Cryptocurrency Monero
". ''Motherboard''. Retrieved 2020-12-17. The contract was awarded to blockchain analysis groups
Chainalysis
Chainalysis is an American blockchain analysis firm headquartered in New York City. The company was co-founded by Michael Gronager and Jonathan Levin in 2014. Its customers have included the United States's Federal Bureau of Investigation, Drug ...
and Integra FEC.
Mining

Monero uses a
proof-of-work algorithm, RandomX, to validate transactions. The method was introduced in November 2019 to replace the former algorithm CryptoNightR.
Both algorithms were designed to be resistant to ASIC mining, which is commonly used to mine other cryptocurrencies such as
Bitcoin
Bitcoin ( abbreviation: BTC; sign: ₿) is a decentralized digital currency that can be transferred on the peer-to-peer bitcoin network. Bitcoin transactions are verified by network nodes through cryptography and recorded in a public distr ...
. Monero can be mined somewhat efficiently on consumer-grade hardware such as
x86,
x86-64,
ARM and
GPUs, a design decision which was based on Monero project's opposition to mining centralisation which ASIC mining creates,
but has also resulted in Monero's popularity among
malware
Malware (a portmanteau for ''malicious software'') is any software intentionally designed to cause disruption to a computer, server, client, or computer network, leak private information, gain unauthorized access to information or systems, depri ...
-based non-consensual miners. In October of 2021 the Monero project introduced P2Pool, a
mining pool running on a
sidechain which gives participants full control of their node as with solo mining configurations.
Illicit use
Monero's privacy features have made it popular for illicit purposes.
Darknet markets
Monero is a common medium of exchange on
darknet market
A darknet market is a commercial website on the dark web that operates via darknets such as Tor or I2P. They function primarily as black markets, selling or brokering transactions involving drugs, cyber-arms, weapons, counterfeit currency, stole ...
s.
In August 2016, dark market
AlphaBay
AlphaBay is a darknet market operating both as an onion service on the Tor network and as an I2P node on I2P. After it was shut down in July 2017 following law enforcement action in the United States, Canada, and Thailand as part of Operation ...
permitted its vendors to start accepting Monero as an alternative to bitcoin.
The site was taken offline by law enforcement in 2017, but it was relaunched in 2021 with Monero as the sole permitted currency.
''Reuters'' reported in 2019 that three of the five largest darknet markets accepted Monero, though bitcoin was still the most widely used form of payment in those markets.
Mining malware
Hackers have embedded malware into websites and applications that hijack victim CPUs to mine Monero (sometimes called
cryptojacking).
In late 2017, malware and antivirus service providers blocked Coinhive, a
JavaScript implementation of a Monero miner that was embedded in websites and apps, in some cases by hackers. Coinhive generated the script as an alternative to advertisements; a website or app could embed it, and use website visitor's
CPU
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...
to mine the cryptocurrency while the visitor is consuming the content of the webpage, with the site or app owner getting a percentage of the mined coins. Some websites and apps did this without informing visitors, or in some cases using all possible system resources. As a result, the script was blocked by companies offering
ad blocking subscription lists, antivirus services, and antimalware services.
Coinhive had been previously found hidden in ''
Showtime
Showtime or Show Time may refer to:
Film
* ''Showtime'' (film), a 2002 American action/comedy film
* ''Showtime'' (video), a 1995 live concert video by Blur
Television Networks and channels
* Showtime Networks, a division of Paramount Global w ...
-''owned streaming platforms and
Starbucks
Starbucks Corporation is an American multinational chain of coffeehouses and roastery reserves headquartered in Seattle, Washington. It is the world's largest coffeehouse chain.
As of November 2021, the company had 33,833 stores in 80 c ...
Wi-Fi hotspots in Argentina.
Researchers in 2018 found similar malware that mined Monero and sent it to
Kim Il-sung University in
North Korea.
Ransomware

Monero is sometimes used by
ransomware
Ransomware is a type of malware from cryptovirology that threatens to publish the victim's personal data or permanently block access to it unless a ransom is paid off. While some simple ransomware may lock the system without damaging any files, ...
groups. According to
CNBC, in the first half of 2018, Monero was used in 44% of cryptocurrency
ransomware
Ransomware is a type of malware from cryptovirology that threatens to publish the victim's personal data or permanently block access to it unless a ransom is paid off. While some simple ransomware may lock the system without damaging any files, ...
attacks.
One group behind the 2017
WannaCry ransomware attack,
the Shadow Brokers
The Shadow Brokers (TSB) is a hacker group who first appeared in the summer of 2016. They published several leaks containing hacking tools, including several zero-day exploits, from the "Equation Group" who are widely suspected to be a branch of ...
, attempted to exchange the ransom they collected in bitcoin to Monero. ''
Ars Technica
''Ars Technica'' is a website covering news and opinions in technology, science, politics, and society, created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews, and guides on issues such as computer hardware and software, sci ...
'' and ''
Fast Company'' reported that the exchange was successful,
but
BBC News reported that the service the criminal attempted to use,
ShapeShift
In mythology, folklore and speculative fiction, shape-shifting is the ability to physically transform oneself through an inherently superhuman ability, divine intervention, demonic manipulation, sorcery, spells or having inherited the ...
, denied any such transfer. The Shadow Brokers began accepting Monero as payment later in 2017.
In 2021,
CNBC, the ''
Financial Times'', and ''
Newsweek'' reported that demand for Monero was increasing following the recovery of a bitcoin ransom paid in the
Colonial Pipeline cyber attack
On May 7, 2021, Colonial Pipeline, an American oil pipeline system that originates in Houston, Texas, and carries gasoline and jet fuel mainly to the Southeastern United States, suffered a ransomware cyberattack that impacted computerized equi ...
.
The May 2021 hack forced the pipeline to pay a $4.4M ransom in bitcoin, though a large portion was recovered by the United States federal government the following month.
The group behind the attack,
DarkSide, normally requests payment in either bitcoin or Monero, but charge a 10–20% premium for payments made in bitcoin due to its increased traceability risk.
Ransomware group
REvil removed the option of paying ransom in bitcoin in 2021, demanding only Monero.
Ransomware negotiators, groups that help victims pay ransoms, have contacted Monero developers to understand the technology.
Despite this, CNBC reported that bitcoin was still the currency of choice demanded in most ransomware attacks, as insurers refuse to pay Monero ransom payments because of traceability concerns.
Regulatory responses
The attribution of Monero to illicit markets has influenced some exchanges to forgo listing it. This has made it more difficult for users to exchange Monero for fiat currencies or other cryptocurrencies.
Exchanges in South Korea and Australia have delisted Monero and other privacy coins due to regulatory pressure.
In 2018,
Europol and its director
Rob Wainwright wrote that the year would see criminals shift from using bitcoin to using Monero, as well as Ethereum,
Dash
The dash is a punctuation mark consisting of a long horizontal line. It is similar in appearance to the hyphen but is longer and sometimes higher from the baseline. The most common versions are the endash , generally longer than the hyphen b ...
, and
Zcash.
''
Bloomberg'' and
CNN reported that this demand for Monero was because authorities were becoming better at monitoring the Bitcoin blockchain.
Publicity
* After many online payment platforms shut down access for
white nationalists following the
Unite the Right rally in 2017, some of them, including
Christopher Cantwell and
Andrew Auernheimer
Andrew Alan Escher Auernheimer ( ; born ), best known by his pseudonym weev, is an American computer hacker and professional Internet troll. Affiliated with the alt-right, the Southern Poverty Law Center has described him as being a neo-Nazi ...
("weev"), started using and promoting Monero.
* In December 2017, the Monero team announced a partnership with 45 musicians and several online stores for Monero to be used as a form of payment for their merchandise.
* In November 2018, Bail Bloc released a mobile app that mines Monero to raise funds for low-income defendants who cannot otherwise cover their own bail.
References
External links
*
{{Portal bar, Economics, Free and open-source software, Internet, Numismatics, Money
2014 software
Cryptocurrency projects
Blockchains
Currencies introduced in 2014
Private currencies
Software using the MIT license
Privacy
Privacy software
Application layer protocols