Privacy coins face a persistent hurdle: they trade off speed for secrecy, or usability for security. Zcoin thinks it has cracked the problem. The project released an academic paper outlining Lelantus,
Privacy coins face a persistent hurdle: they trade off speed for secrecy, or usability for security. Zcoin thinks it has cracked the problem. The project released an academic paper outlining Lelantus, a new protocol the team plans to deploy next year.
Zcoin builds privacy-focused cryptocurrency. In November the project embedded a Thai song into its blockchain to resist censorship. Now it's releasing the technical blueprint for what it believes solves the core problems holding back privacy coins.
"Current privacy protocols need to be improved. Most require tradeoffs on either scalability, anonymity, ease of use or they are underprinned by experimental cryptography. We created Lelantus to tackle these issues and offer a well-rounded solution to users," said Reuben Yap, chief operating officer of Zcoin, in a statement.
Zcoin uses Zerocoin, a protocol that masks transactions through zero-knowledge proofs. But Zerocoin locks users into fixed coin denominations to maintain anonymity. Lelantus keeps the same privacy guarantees while dropping that constraint. Users gain flexibility. The user experience improves.
The technical gains matter more. Lelantus zero-knowledge proofs consume 1.5 kilobytes per transaction on the blockchain. Zerocoin proofs take 25 kilobytes. The difference compounds across millions of transactions.
Lelantus also avoids a trusted setup, the cryptographic bootstrap phase where developers destroy initial parameters to prevent unlimited coin creation. Many competing privacy systems depend on this step. Lelantus doesn't.
Aram Jivanyan, the researcher who designed Lelantus and serves as Zcoin's cryptography advisor, explained the approach. "Performance is a crucial aspect in any transaction privacy protocol and must be practical to implement. Many privacy protocols use zkSNARKs to improve computations, but Lelantus is able to achieve this without a trusted setup by sticking to well established cryptographic assumptions. It it both fast and storage-efficient without compromising on privacy and confidentiality," Jivanyan said.
The protocol handles multiple transactions in a single block. It hides transaction amounts. It removes denominations altogether. Zcoin sees these shifts as the building blocks for privacy coins that don't ask users to choose between anonymity and functionality.
