Alloc Init Researchers Unveil Shielded Bitcoin Protocol

Researchers from alloc init have proposed a new protocol called Shielded Bitcoin, aiming to bring strong privacy features to Bitcoin transactions without requiring any modifications to the underlying network. The proposal was submitted by Clara Shikhelman, Misha Komarov, and Aleksei Moskvin.

The key innovation behind Shielded Bitcoin is its ability to mask transactions using a unique prefix, such as 'shbtc:', which can be embedded in Bitcoin transactions through various methods like OP_RETURN or witness fields. This approach ensures that the Bitcoin network itself does not verify or enforce these shielded transactions, allowing for a high degree of anonymity.

The protocol relies on a novel concept called nullifiers to track spent coins without deleting them from the UTXO set. Shielded Bitcoin indexers use zero-knowledge proofs to ensure that each nullifier corresponds to a valid output, providing protection against double-spending attacks similar to Bitcoin's.

According to the proposal, users can recover their funds using only a single Bitcoin node and a Shielded Bitcoin indexer, eliminating the need for service providers or chain state coordination. The researchers claim that Shielded Bitcoin offers comparable privacy features to Zcash's shielded pools.