HARMONY : Open Consensus for 10B people


Harmony is new open infrastructure distinguished by its revolutionary high-throughput, low-latency, and low-fee consensus platform designed to power decentralized economies of the future. Harmony is next generation blockchain which is based on sharding .Harmony is fully scalable, secure and energy efficient. Harmony has following awesome features :

  1. Highly Scalable : Harmony is a highly scalable blockchain as it shards not only the network communication and transaction validation like Zilliqa, but also shards the blockchain state.
  2. Secure Sharding: Harmony’s uses distributed randomness generation (DRG) process which is unpredictable, unbiaseable, verifiable and scalable in its sharding process which makes it secure . Harmony also reshards the network in a non-interruptive manner to prevent against slowly adaptive byzantine adversaries.
  3. Efficient and Fast Consensus: Harmony is based on POS which makes the harmony energy efficient . Harmony uses an improved version of PBFT Fast Byzantine Fault Tolerance (FBFT) that is 100 times faster than PBFT.
  4. Adaptive-Thresholded PoS: 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.
  5. Scalable Networking Infrastructure: 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 to achieve cross-shard transactions that scale logarithmically with the number of shards.
  6. Consistent Cross-Shard Transactions: 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.

Harmony innovates on both the protocol as well as network layer . This makes harmony a highly scalable and secure blockchain.

Now , when you aim so much high , you should have the capability in the team to do so and that’s what exactly Harmony has . Let’s look at the great minds behind harmony


In the blockchain space , you rarely find team with so much expertise in academic research, global-scale engineering, and long-term company building. The members have built the highly scalable system in the top tech companies . The team members have worked at the likes of Apple ,Google , Amazon etc in the past . They have worked on exciting projects at Google Maps, Apple Siri, and AWS Infrastructure . So the team is more the capable of achieving what their vision is . Let’s look at the credentials of some of the team member to understand their level of expertise :

  1. Stephen Tse : Stephen was a researcher at Microsoft Research, a senior infrastructure engineer at Google, and a principal engineer for search ranking at Apple. He founded the mobile search Spotsetter with institutional venture capital; Apple later acquired the startup.
  2. Nicolas Burtey: Nicolas holds a bachelor’s degree in mathematics and computer science, and a master’s degree in computational photography. His master’s thesis at Ecole Nationale Supérieure Louis Lumière was titled “The representation of space and time in panoramic photography.”
  3. Alok Khatri : Alok Kothari worked on deep learning models for natural language understanding at Apple’s Siri. He conducted research in natural language processing, information retrieval machine learning and published at top conferences like SIGIR, ICWSM and EMNLP. His research paper won the best dataset award at ICWSM 2013.

4. Nick White: Nick White holds bachelor’s and master’s degrees in electrical engineering from Stanford University, where he focused on signal processing, optimization and control. As a graduate teaching assistant at Stanford, he researched artificial intelligence and applied mathematics with Prof. Bernard Widrow.

5. Rongjian Lan : Rongjian Lan was a search infrastructure engineer for Play Store at Google. He published over 10 academic papers on spatio-temporal querying and map-based visualization. Rongjian started researching on decentralized protocols since early 2017. Rongjian is the co-chair of ABC Blockchain Foundation, with more than 100 engineers from Google, Facebook, LinkedIn as members. He was a doctoral candidate of computer science at the University of Maryland College Park and obtained his bachelor’s degree from the University of Science and Technology Beijing.

As you can see , there is lot of experience there . There is a long list of more awesome people in the team. What we can say is the team is top notch and you can certainly look at them and trust them to deliver.


We all know , for any blockchain protocol , consensus is an important key . It determines how securely and quickly blockchain validators reach consensus on the next block. Harmony’s consensus protocol is linearly scalable in terms of communication complexity called Fast Byzantine Fault Tolerance (FBFT). In FBFT, instead of asking all validators to broadcast their votes, the leader runs a multi-signature signing process to collect the validators’ votes in a O(1)-sized multi-signature and then broadcast it. So instead of receiving O(N) signatures, each validator receives only one multi-signature, thus reducing the communication complexity from O(N ^2) to O(N).

The validators of Harmony’s consensus are elected based on Proof-of-Stake. Therefore, the actual protocol differs slightly from the one described above in a sense that a validator with more voting shares has more votes than others, rather than one-signature-one-vote. So instead of waiting for at least 2f + 1 signatures from validators, the leader waits for signatures from the validators who collectively possess at least 2f + 1 voting shares.


Sharding has been talked about lot in blockchain space . There are a lot of projects working on it . Harmony contains a beacon chain and multiple shard chains. The beacon chain serves as the randomness beacon and identity register, while the shard chains store separate blockchain states and process transactions concurrently. Harmony proposes an efficient algorithm for randomness generation by combining Verifiable Random Function (VRF) and Verifiable Delay Function (VDF). Harmony also incorporates PoS in the sharding process which shifts the security consideration of a shard from the minimum number of nodes to the minimum number of voting shares.

Shard Chain and Beacon Chain:

A shard chain is a blockchain that processes and validates its own transactions and stores its own state. A shard only processes transactions that is relevant to itself. Although a shard chain is relatively independent, it will communicate with other shard chains through cross-shard communication. Cross-shard Communication Cross-shard communication is a key component of any sharding-based blockchain. Cross-shard capability breaks the barrier between shards and extends the utility of a single shard beyond itself.Harmony adopts the shard-driven approach for its simplicity and the absence of burden on clients. We believe the benefits of shard-driven communication outweighs its drawbacks. The cost on the overall network for shard-driven communication can be considerable because every cross-shard message is a network-level broadcast, which incurs a O(N) network cost. To solve this problem, Harmony uses the Kademlia routing protocol to reduce the communication complexity to O(log(N)) . In addition, the data being communicated will be encoded with erasure code to ensure the robustness of cross-shard communication

The Harmony beacon chain is a special blockchain that serves additional purposes compared to the shard chains. In effect, the beacon chain is also a shard. Besides processing transactions, like other shard chains do, the beacon chain is in charge of two additional key functionalities: generating the random number and accepting stakes, which means that the beacon chain is the chain where stakers deposit their tokens to become validators.

Harmony has a concept of blockchain state sharding which is unique . Let’s understand that more .

Blockchain State Sharding

Unlike other state-sharding blockchains that adopted UTXO (Unspent Transaction Output) data model, Harmony’s state sharding is applied on account-based data model. Each shard chain contains its own account state, and all the tokens in existence are spread among all the shard. We treat the user account and the smart contract account differently in sharding. An user account can have multiple balances at different shards (e.g. 100 tokens at Shard A and 50 tokens at Shard B). A user account can move its balance between shards by issuing a cross-shard transaction. A smart contract account is limited to the specific shard where the contract was created. However, for a decentralized application that requires more throughput than a single shard can handle, the Dapp (Decentralized Application) developer can instantiate multiple instances of the same smart contract in different shards and let each instance handle a subset of the incoming traffic. Note that the different instances of the same smart contract do not share the same state, but they can talk to each other via cross-shard communication.


Harmony testnet has been launched in Feb 2019. Testnet launch includes many important landmarks which are listed as below :

  • Faster consensus using BLS multi-signatures & gossiping broadcast
  • Node staking on beacon chain using smart contracts
  • Secure resharding with Cuckoo Rule
  • Robust peer discovery via libp2p bootnodes & Kademlia routing

Harmony is planning for its mainnet launch and it’s working with full pace to achieve this well ahead.

As we conclude , we can say that Harmony is one of the top notch project which is coming out with it’s mainnet this year . This project stands in the top list where the likes of Dfinity , Thunder ,Oasis resides. This one can be the winner of the all . With the team having so much of past expertise , we should better believe.

Please watch this interview of Blockchain brad with Harmony team to learn more .

Telegram : https://t.me/harmony_one

Twitter: https://twitter.com/harmonyprotocol

Website : https://harmony.one

Medium : https://medium.com/harmony-one