The Aztec Protocol is an efficient zero-knowledge privacy protocol designed to enable private transactions on the Ethereum blocckhain. Their zero-knowledge proofs enable private transactions that can facilitate a variety of inter-operable financial applications on Ethereum. Aztec is a ConsenSys portfolio company.

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XinFin is a blockchain technology company that has developed the XDC protocol. XinFin's hybrid blockchain enables peer-to-peer contracts on a regulated payment infrastructure. Their goal is to create an open source marketplace platform that will reduce inequalities in global finance.
The XDC blockchain is built upon Quorum, a permissioned blockchain developed by J.P. Morgan. Quorum was developed as a layer upon the Go implementation of the
Ethereum protocol. XDC's consensus mechanism allows for new blocks be created in a two-step process. In the first step, the transactions to be included in the new block are voted upon by all participating nodes. In the second step, one node is selected as the leader or block maker randomly. The block maker node then creates the new block.
XInFin is powered by the XDCE token.

QuarkChain is building a blockchain with a focus on speed and scalability. They hope to significantly improve transaction times and reduce fees with an architecture that will rely on a two-layered blockchain and elastic sharding. QuarkChain uses a hybrid Proof-of-Work (PoW) consensus mechanism that is ASIC-resistant. Transactions are first confirmed on one blockchain layer, and then on the second. The network will be powered by the QKC coin.