A new proposal for Shielded Bitcoin aims to enhance privacy in transactions using elements from Zcash while operating on the existing Bitcoin network.
Researchers Unveil New Protocol for Private Transactions
A team from the cryptography firm [[alloc] init] has presented a new protocol called Shielded Bitcoin, designed to enhance the privacy of transactions on the Bitcoin network. This innovative framework aims to obscure sender and recipient identities and transaction amounts while utilizing Bitcoin's existing infrastructure.
The comprehensive 56-page document, dated September 24, 2026, was collaboratively developed by researchers Clara Shikhelman, Mikhail Komarov, and Aleksei Moskvin. Shikhelman highlighted the extensive efforts put into ensuring the protocol's security and understanding the data it may reveal, while Komarov emphasized its similarity to Zcash's privacy features, referring to it as "ZCash-style privacy on the Bitcoin L1 via PIPEs v2".
"ZCash-style privacy on the Bitcoin L1 via PIPEs v2." — Mikhail Komarov
Scott Odell, COO of [[alloc] init], mentioned on social media that the firm has been developing this protocol for an extended period, stressing its potential to bolster privacy without modifying Bitcoin's core structure.
Mechanics of the Shielded System
In this new privacy framework, value is represented as encrypted "notes," with each transaction accompanied by a zero-knowledge proof that verifies the sender's control over the notes and maintains balance in inputs and outputs. A nullifier is used to prevent double spending while keeping the specific notes used confidential.
Unlike Zcash, which operates on its own blockchain, Shielded Bitcoin records transactions as data on the Bitcoin network. Validation is handled by separate software known as indexers, which confirms proofs and reconstructs the shielded state. The authors noted that while metadata such as transaction timing and fees remain public, details about the participants and amounts exchanged are confidential, aligning with the privacy features of Zcash and Monero.
The current proposal does not address how Bitcoin will enter or exit the shielded system. Future documentation is expected to clarify these mechanisms, based on prior work involving Bitcoin PIPEs v2, which aims to secure signing keys for recovery only with valid proof systems. Currently, the method uses the Groth16 proof system, and transactions are published using an OP_RETURN output method, which is limited by the Bitcoin Core v30 default settings.
Furthermore, an appendix suggests a potential compliance layer where a "Trust Authority" could certify approved deposits, allowing institutions to validate a note's origin without exposing full transaction details. Notes without such certification would still be valid for transactions.
Drawing inspiration from Zcash, which is actively traded through regulated funds in the U.S. and Europe, Shielded Bitcoin could potentially expand privacy options for Bitcoin users if successfully implemented.
