Researchers from [alloc] init published a proposal Thursday for private bitcoin payments without altering the network's core rules. The "Shielded Bitcoin" pa authored by Clara Shikhelman, Mikhail Komarov, and Aleksei Moskvin, draws directly from Zcash's encrypted payment design.
The system would allow bitcoin-denominated value to be held in encrypted records called notes. Spending a note would publish a marker indicating its use along with a mathematical proof confirming the sender owned the funds and did not create new ones. The transaction amount, sender, and recipient would remain hidden from public view.
Unlike Zcash's blockchain, which verifies proofs directly, Shielded Bitcoin would publish transfer data on the Bitcoin network and delegate proof checks to separate software any user could run. A Bitcoin transaction could be confirmed even if the private payment recorded within it failed Shielded Bitcoin's internal checks.
Users would possess wallet keys to reconstruct accepted payments from the public record. Separate viewing keys would enable them to disclose specific transactions to accountants or auditors, offering controlled transparency.
The proposed system currently lacks a finalized mechanism to lock up real BTC and release it again—a critical step for practical implementation of private bitcoin-denominated transfers.
Privacy has become a practical concern for developers making cryptocurrencies viable for payroll, business payments, and daily spending. Standard bitcoin transactions permanently expose amounts and addresses, making subsequent payments easier to track once an address is linked to an entity.
Ethereum is also reviewing a proposal for a shared private pool, allowing users to transfer ether and other tokens without publicly revealing payment details. Authors cited payroll, treasury management, and donations as uses poorly served by fully public transactions.
Zcash, which launched as a separate cryptocurrency in 2016, offers users a choice between transparent public payments and shielded encrypted payments. Its shielded pools held approximately 4.9 million ZEC on Friday, a 14 percent increase from July 30, representing about 29 percent of all issued ZEC.
Shielded ZEC value totaled approximately $7.8 billion following a significant price rally. Zcash recorded roughly 63,000 shielded transactions last week, its busiest week for private transfers since 2022 and fourth-highest on record.
Zcash network transfer volume exceeded $23 billion last week—the largest weekly total since 2021 and second-highest in the network's history. ZEC gained more than 2,300 percent over the preceding year by early September, crossing $1,000 and extending its rally above $1,600 by Wednesday.
The connection to Zcash traces to 2013 with the Zerocoin proposal, an early privacy extension for Bitcoin. Subsequent Zerocash research ultimately led to Zcash's development and launch.
