Zero-knowledge proving system ‘Halo’ now licensed under MIT or Apache 2.0, making it available for anyone to use

New agreement between Filecoin Foundation and Electric Coin Co. also creates grant pool of up to $9M for Filecoin-Zcash projects.

A new agreement between the Filecoin Foundation, the organization that facilitates governance of the Filecoin network, and Electric Coin Co. (ECC) makes the Halo 2 codebase available to everyone under an MIT or Apache 2.0 open-source license and launches a new RFP-style grants program.

The Halo 2 licensing news has implications for any entrepreneur or project interested in implementing trustless and recursive zero-knowledge-proof cryptography, a technological breakthrough discovered by ECC’s Sean Bowe. For example, the Ethereum Foundation is already using part of Halo 2 for their zero-knowledge EVM project and is investigating Halo 2 for other Ethereum-wide use cases.

From Vitalik Buterin, Co-Founder of Ethereum, “The Zcash (ECC) team’s work on Halo is both an amazing work of mathematical and cryptographic genius and a significant advancement in the security and efficiency properties that zero knowledge proof protocols can have. I look forward to seeing more work and more applications in and on top of the Ethereum protocol and the crypto spaces as a whole using Halo code and technologies!”

Halo 2 was originally released under the Bootstrap Open Source License (BOSL), which gives everyone equal access to the code and equal rights to improve that code commercially as long as they open-source their improvements and make those improvements available under BOSL after 12 months. To foster greater collaboration and reuse, Halo 2 is now shared under the more common and permissive MIT license or Apache 2.0 license. Orchard, the Zcash payment protocol built on Halo 2, will remain under BOSL.

In September 2021, Filecoin Foundation and ECC, along with Protocol Labs and the Ethereum Foundation, revealed a multi-faceted collaboration focused on Halo 2. It kicked off a series of plausible collaborations between the projects, according to Zooko Wilcox, ECC Founder and CEO.

“The Zcash, Filecoin, and Ethereum communities have a shared vision of an internet that is open to all and that honors the agency of every user and every community,” he said. “We call this vision Web3. These partnerships and these technologies will create a cornerstone for that world.”

The Halo 2 proving system will be implemented in Zcash this year at network upgrade 5. This will remove the trusted setup and pave the way for scalability and cross-chain interoperability.

Filecoin-Zcash grants

Another significant outcome of the Filecoin Foundation-ECC agreement is the creation of a joint grants pool with up to $9 million available for Filecoin and Zcash projects.

The grant program includes a base pool of $5M, provided by Filecoin Foundation, plus additional matching funds for any ECC contributions up to $2M, for a total potential pool size of $9M. Funds will be jointly administered by Filecoin Foundation and ECC.

“Filecoin Foundation is thrilled to expand our collaboration with ECC to build tools that improve interoperability between Filecoin and Zcash and to open up more opportunities for builders to get involved in these two projects,” said Marta Belcher, Filecoin Foundation President and Board Chair.


Any proposal that leads to additional utility for both FIL and ZEC chains and their respective ecosystems will be considered, and innovation is encouraged. A few of the specific opportunities that have been discussed to date are below. Teams are welcome to build proposals based on these ideas or on other collaborations that will add utility to the FIL and ZEC chains.

Filecoin storage payments in ZEC

It would be highly beneficial to both the Filecoin and Zcash ecosystems if Filecoin storage payments could be made in ZEC, affording the same level of privacy for storage purchases that exists in Zcash shielded transfers.

Media and file support in Zcash encrypted memos and NFTs

This support would add the ability to encrypt files in Filecoin storage and add support to mobile clients so that they could “attach” media or files to a Zcash encrypted memo. 

Zero-knowledge virtual machine

The Filecoin Virtual Machine project will be released in milestones across 2022 has been announced, and ECC is interested in a general programming capability, as well. There are a number of projects exploring zero-knowledge technology to improve privacy and security of virtual machine execution. 

For more information about the program, email [email protected].

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