Oasis Network RFP: Sapphire Confidential Fungible Token Standard

Oasis Network recently launched the Sapphire Paratime- the industries first and only confidential EVM. We just published an RFP for Sapphire Confidential Token Standard. Please feel free to contact me with any questions, or if you're interested in building on Sapphire.

Motivation

A confidential fungible token (CFT) that hides at least one of {sender, recipient,amount}
can offer a more complete privacy solution to both dapps and users. A CFT standard will encourage interoperability among dapps, improved tooling for developers, and more convenience for end users.

Example Use-Cases

• A Web3 gaming company wants to to offer in-game purchases, but doesn't want competitors to identify its most valuable customers.
• a DAO wants to purchase a physical good but wants to prevent other potential buyers from one upping their offer
• incentive-compatible (sealed-bid second-price) NFT auctions
• improved DeFi: MEV-resistent DEX, privacy for users of KYC'd lending protocols

Requirements

• ERC-20 ABI compatible
• supports variants hiding any/all of {sender, recipient,amount}
  from entities who are not the sender or recipient
• variants able to be generated using a wizard
• conducive to side-channel resistant implementations
• minimal runtime overhead for ERC-20 methods when compiler optimizations are enabled

Each variant (if multiple) can be in one ADR but have its own name, if desired (e.g., "ADR-18 Semi-Private").

Desirable Features

These features are highly useful, but may be added in future standards application or platform. If not solved in the proposal, these features must not be precluded by the proposal.

• receiver can be efficiently notified of an inbound transfer.