Namecoin is a blockchain-based DNS that allows users to register domain names with a ".bit" domain. Namecoin was the first fork of the Bitcoin protocol and it aims to remove centralized control over domain registration. It was the first cryptocurrency to use Auxiliary Proof of Work (AuxPoW) as a consensus mechanism,
where a child blockchain is dependent on the Proof-of-Work consensus of the parent blockchain. This allows for Namecoin and Bitcoin to be mined simultaneously, and when a new block is created on Bitcoin, it will also be added to the Namecoin blockchain.
Namecoin is a very important project that represents one of the best use cases of blockchain technology in protecting free speech and resisting censorship on the internet. It is powered by the NMC coin. The decentralized DNS provides more security from hackers and government intervention.

HYCON is a blockchain platform powered by the Hyperconnected Coin. The decentralized platform has a Directed Acyclic Graph (DAG) architecture, and is focused on improving scalability and throughput. HYCON's SPECTRE consensus algorithm is designed to enable horizontal scalability, where several blocks can be added at the same time.

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Chromia is a relational blockchain platform that is designed to be both a blockchain and a relational database. Chromia was created by a Swedish development company called ChromaWay, with the intention of combining the advantages of a blockchain's transparency with the benefits of a relational database system, such as data independence and reduced redundancy.