Monero

Monero (XMR) s an open-source cryptocurrency created in April 2014 that focuses on privacy and decentralization that runs on Windows, macOS, Linux, Android, FreeBSD and DragonflyBSD. Monero uses a public ledger to record transactions while new units are created through a process called mining. Monero aims to improve on existing cryptocurrency design by obscuring sender, recipient and amount of every transaction made as well as making the mining process more egalitarian.

The focus on privacy has attracted illicit use by people interested in evading law enforcement. The egalitarian mining process made it viable to distribute the mining effort opening new funding avenues for both legitimate online publishers and malicious hackers who covertly embed the mining code into websites and apps.

Architecture
Unlike many cryptocurrencies that are derivatives of Bitcoin, Monero is based on the CryptoNight PoW hash algorithm, which comes from the CryptoNote protoco. It possesses significant algorithmic differences relating to blockchain obfuscation. By providing a high level of privacy, Monero is fungible, meaning that every unit of the currency can be substituted by another unit. This makes Monero different from public-ledger cryptocurrencies like Bitcoin, where addresses with coins previously associated with undesired activity can be blacklisted and have their coins refused by other users.

In particular, the ring signatures mix the spender's address with a group of others, making it exponentially more difficult to establish a link between each subsequent transaction. Also, the "stealth addresses" generated for each transaction make it impossible to discover the actual destination address of a transaction by anyone else other than the sender and the receiver. Finally, the "ring confidential transactions" mechanism hides the transferred amount.

Monero is designed to be resistant to application-specific integrated circuit mining, which is commonly used to mine other cryptocurrencies such as Bitcoin. It can be mined somewhat efficiently on consumer grade hardware such as x86, x86-64, ARM and GPUs.

Beyond CryptoNote
The algorithm behind Monero is continuously updated every six months in the form of forks in order to prevent ASICs from catching up. This has created an extra layer of maintenance as a consequence. The Monero developers and some in the community have expressed interest in moving to better algorithms or hashing functions.