A key issue with current smart contracts is that on-chain data is highly transparent. All operations are exposed externally, which poses a dilemma for applications that need to protect business logic or user privacy.

Picklin contracts propose a different approach: embedding privacy protection into the contract execution process. Simply put, when writing a contract, you can mark which state variables need to be kept confidential, similar to using the private keyword in traditional programming. The difference is—these private variables are not visible in plaintext even to the contract itself; all operations must be performed through zero-knowledge proofs.

What’s the advantage of this? Consider a privacy-preserving auction scenario. Traditional contracts find it difficult: bid information is either publicly visible on-chain or stored off-chain with trust placed in an intermediary. Picklin contracts keep the entire bidding process encrypted throughout execution. The contract can verify that "this bid is valid and higher than the previous one" without seeing the actual number. Only at the end of the auction, during the reveal phase, is the result decrypted and made public. It’s like an honest blind auctioneer—accepting sealed bids, determining the highest bid, but never knowing the actual bid values.

From an application design perspective, this breaks the previous trade-off between privacy and functionality. Developers can now build truly privacy-preserving applications rather than relying on complicated workarounds. Of course, the learning curve is steeper, requiring adaptation to this new programming paradigm.

For scenarios that require privacy protection with on-chain verification—such as privacy financial contracts, confidential bidding mechanisms, or privacy governance voting—this approach is worth paying attention to.