ZCoin is a privacy focused cryptocurrency built on Ethereum. The ZCoin protocol enables anonymous transactions with cryptography that utilizes Zero-Knowledge Proofs (ZKP). ZCoin increases privacy on their network by using a coin-mixer contract that wraps transactions in a serial number and destroying wrapped coins once they have been redeemed.
Zcoin was the first cryptocurrency to use a Merkle Tree Proof (MTP) as its proof of work algorithm. Merkle Tree Proofs are an innovative solution to achieving network consensus, and can increase transaction time while reducing the centralizing tendency of ASIC mining.

Dogecoin is a cryptocurrency with a focus on fun, generosity, and community. It is unlike many other blockchain projects in that it does not aim to solve any ambitious problems. Dogecoin was originally created as a meme coin and has gained a large following that use the coin (DOGE) as an internet tipping and fundraising system.
Although Dogecoin was first created as somewhat of a joke, it has a passionate community that has used the platform for a variety of purposes. The project has gained widespread publicity and DOGE is traded on many exchanges.

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ICON (ICX) is unique compared to most other digital currrencies. ICON's primary objective is to establish a unifying system to integrate an unlimited numbers of blockchains. This would allow numerous blockchains to work together and incorporate aspects of all of them. ICON is powered by a unique system called loopchain, that can adopt different features, rules, and consensus systems. The loopchain has different circles, with nodes that connect it. There are community nodes and individual nodes that are all connected to the ICON Republic, which is the entire ecosystem. These nodes can connect in countless ways and results in unlimited applications. The network has an innovative consensus mechanism called Delegated Proof-of-Contribution (DPoC).