Alloc Init Unveils 'Shielded Bitcoin' Proposal to Bring Zcash-Style Privacy to Bitcoin

According to Woofun AI, the crypto research team Alloc Init has officially launched a "Shielded Bitcoin" proposal designed to enable privacy-preserving transactions similar to Zcash on the Bitcoin network—without triggering a soft fork. The initiative seeks to restructure Bitcoin's transaction privacy layer through technical means while preserving the underlying consensus mechanism, offering a new path toward balancing compliance and privacy for Bitcoin users long constrained by the blockchain's transparent ledger. The proposal marks the latest attempt to apply zero-knowledge proof technology in a mainstream public blockchain sidechain context.

Technical Blueprint Released

Clara Shikhelman, Mikhail Komarov, and Alexei Moskvin jointly published the technical blueprint on Thursday. The core architecture departs from the traditional approach of having miners execute privacy protocols, instead treating Bitcoin as a neutral publication and ordering layer. Under this framework, specialized indexer software assumes critical responsibilities: verifying zero-knowledge proofs, confirming that funds have not been double-spent, and reconstructing the privacy system's state.

Design Inspired by Zcash

Data compiled by Woofun AI indicates that the design draws heavily from Zcash's logic, employing encrypted notes, a public nullification mechanism to mark note consumption, and zero-knowledge proofs to ensure transaction validity. Notably, "Shielded Bitcoin" does not create an independent blockchain or consensus mechanism but relies entirely on existing infrastructure for state synchronization and verification.

Privacy Concerns Over User Base Size

However, the effectiveness of privacy protection is closely tied to user base size—a structural weakness that has drawn sharp scrutiny from industry experts. Developer Vadim Zavodir noted on X that privacy depends on the size of the user group. Zcash took years to build an effective anonymity set, while a new system starting from scratch could initially face a "one-person anonymity set" dilemma. The researchers also acknowledged in their accompanying paper that large deposits do not automatically translate into high anonymity. If a small number of users dominate encrypted note creation, or if specific wallets exhibit unusual behavioral patterns, observers could still trace transaction links through on-chain analysis.

Security and Quantum Resistance Under Fire

On the security front, Pierre-Luc Dalais-Demers, founder of Pauli Group, offered sharp criticism, arguing that the proposal completely lacks resistance to quantum attacks. While he is exploring an alternative version based on post-quantum signature schemes, the current architecture remains highly vulnerable to the threat of quantum computing. In contrast, Eli Ben-Sasson, co-founder of Zerocash and CEO of StarkWare, expressed support. He noted that the original Zerocash paper was intended to bring privacy to Bitcoin, and although he has not yet read the new paper in detail, he looks forward to seeing the vision of achieving privacy and scalability through zero-knowledge proofs become a reality.