Monero is a decentralized public ledger protocol whose focus is on increased privacy. It was created in 2014, with the goal of establishing a privacy focused blockchain that would allow users to send and receive transactions anonymously, and not pseudo-anonymously, like Bitcoin.
Monero uses an obfuscated public ledger that prevents anyone from determining the source, destination, or amount of payments. Unlike many other cryptocurrencies, payments and account balances on Monero remain entirely hidden. This is one reason that XMR, the Monero currency, has attracted some users that are involved with illicit activities.
Monero uses a Proof of Work consensus mechanism that requires less computing power from miners than Bitcoin does. Because of this, mining Monero has become an alternative source of revenue for some websites and apps. .

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Grin Coin is a community driven blockchain project that aims to create a lightweight mimblewimble blockchain that will enable anonymous transactions. Grin has a Proof-of-Work consensus mechanism. Transactions are executed while hiding addresses and amounts.

Bitcoin Private is a community-driven fork of the Bitcoin protocol. It is somewhat unique in that it was created as a result of a privacy-focused co-fork of Bitcoin and ZClassic. Coins were distributed on a 1:1 basis to BTC and ZCL holders. Bitcoin Private (BTCP) uses the same privacy technology as ZClassic (zk-snarks). Transactions are published on a public blockchain, but the sender, recipient and other transactional metadata remain anonymous. Bitcoin Private has a larger block size, and enables anonymous transactions that are more secure than the original Bitcoin protocol.