Harmony

Harmony, the next generation sharding-based blockchain that is fully scalable, provably secure, and energy efficient. Harmony addresses the problems of existing blockchains by combining the best research results and engineering practice in an optimally tuned system.

Specifically, Harmony makes breakthroughs in following aspects:

Harmony shards not only the network communication and transaction validation like Zilliqa, but also shards the blockchain state. This makes Harmony a fully scalable blockchain.

Unlike other sharding-based blockchains which require PoW to select validators, Harmony is based on PoS and thus energy efficient. Consensus is reached with a linearly scalable BFT algorithm that’s 100 times faster than PBFT.

Unlike other sharding-based blockchains which require PoW to select validators, Harmony is based on PoS and thus energy efficient. Consensus is reached with a linearly scalable BFT algorithm that’s 100 times faster than PBFT.

The threshold of stakes required for a node to join the network is adjusted based on the volume of total staking in a way that malicious stakers cannot concentrate their power in a single shard. Moreover, the threshold is low enough so that small stakers can still participate in the network and earn rewards.

With RaptorQ fountain code, Harmony can propagate blocks quickly within shards or across network by using the Adaptive Information Dispersal Algorithm. Harmony also adopts Kademlia routing [37] to achieve cross-shard transactions that scale logarithmically with the number of shards.

Harmony supports cross-shard transactions with shards directly communicating with each other. An atomic locking mechanism is used to ensure the consistency of cross-shard transactions.

By innovating on both the protocol and network layers, Harmony provides the world with a scalable and secure blockchain system that is able to support the emerging decentralized economy. Harmony will enable applications which were not previously feasible on blockchain, including high-volume decentralized exchanges, interactive fair games, Visa-scale payment systems, and Internet-of-Things transactions. Harmony strives to scale trust for billions of people and create a radically fair economy.