The testnet for Ethereum's next big update has successfully verified an important part of a transaction with the virtual cryptocurrency Zcash, bringing the dream of making the blockchain network more privacy-focused just a tiny bit closer to reality.
In blockchain protocols such as Bitcoin, all the nodes have to validate all the transactions and can see what they are. Unlike Bitcoin, Zcash uses cryptographic tech called "zero-knowledge succinct non-interactive arguments of knowledge" (zk-SNARKs) to let its chain validate transactions that are encrypted, offering additional privacy.
Byzantium is the next major hard fork of Ethereum, which began testing Tuesday. On the same day, a smart contract verified that some sender on the Zcash network sent money to some recipient on the Zcash network, but there is no info about who they are or how much was spent.
That's the zk-SNARK part of the Zcash transaction.
Given the clear advantages, there have been several proposals to tie Zcash's anonymity protections into Ethereum. For example, there's zk-SNARKs in Ethereum, Hawk and the "Project Alchemy" integration bridge idea.
Bas van Kervel, an Ethereum developer based in the Netherlands, told The Register that "verifying zk-SNARKs is a computational heavy task if implemented in pure smart contracts" so the system uses some optimisations behind the scenes. "This is the first step to make projects like [Project Alchemy] possible," he said.
Elliot Shepherd, VP of technology at identitii, which offers a database built on blockchain tech, told The Reg that the validation test is "absolutely significant in a view of how disparate chains could work together".
Some are cautious.
Eli Ben-Sasson, a computer scientist at Technion – Israel Institute of Technology i...