Horizen is a blockchain ecosystem focused on privacy and scalability, using its sidechain solution, Zendoo, to support the creation of both public and private blockchains and decentralized applications. It incorporates the zero-knowledge proof protocol (zk-SNARK) for secure communications. Horizen's infrastructure, including Zendoo and the node system, enables developers to custom-build blockchains and dApps with flexibility in consensus mechanisms, speed, privacy settings, and economic models. The platform is also EVM-compatible through its EON sidechain, offering developers a wide range of customization options.
Horizen was launched in May 2017 under the name ZenCash. The project set out with the goal of building zero-knowledge-proof technologies, a sustainable funding model, and the desire to adequately incentivize stakeholders and build an ecosystem.
On 3rd June 2018, ZenCash experienced an attempted 51% attack. The attackers managed to create 3 double spend transactions of 3317.4, 6,600, and 13,234.9 ZEN. In response, the team amended the consensus mechanism and introduced a penalty for delayed block reporting. The solution makes it exponentially more difficult and costly for malicious actors trying to perform a 51% attack. The solution is also being used by other projects, such as Pirl.
As ZenCash grew in popularity, it constantly found itself being confused with another crypto project called Zcash. In addition, the word “cash” in the project’s name was presenting it as merely a digital currency and yet the project was looking at product offerings like a decentralized treasury and sidechains. The team decided that it was time for a rebrand.
In August 2018, the project was rebranded to its current name, Horizen. This marked the project's evolution from simply a cryptocurrency to a privacy platform with a focus on scalability.