Proposal for a Zcash-style privacy feature on Bitcoin without a soft fork Researchers at [[alloc] init] have proposed “Shielded Bitcoin”—a protocol enabling private BTC transfers using Zcash’s model, directly on Bitcoin, without requiring a soft fork or hard fork. The design employs “encrypted notes,” public nullifiers, and zero-knowledge proofs to conceal transaction amounts, senders, recipients, and links between transactions. Bitcoin primarily serves as a data storage and ordering layer, while a dedicated indexer tracks and verifies the system’s state. The solution leverages Bitcoin PIPEs and witness encryption, enabling zero-knowledge proof verification to interoperate with existing Bitcoin signatures. However, the technology remains in the research phase, and a complete mechanism for depositing and withdrawing $BTC into/from the private pool is still under development. A shielded transaction is expected to be approximately 700 vbytes in size—significantly larger than standard Bitcoin transactions, which range from 100–200 vbytes—implying fees could be roughly four times higher.