Zama Fhevm Solidity Core

Zama FHEVM Solidity Core

Introduction

This skill is the main entry point for Zama FHEVM Solidity development. It helps agents understand and implement confidential smart contracts based on @fhevm/solidity.

The core FHEVM Solidity workflow is to declare encrypted types in Solidity, verify encrypted inputs submitted off-chain, compute in the encrypted domain, use ACL rules to control later handle usage and decryption permissions, and support user decrypt or public decrypt when appropriate.

Usage Principles

• Read the current project's dependencies and configuration before choosing API syntax.
• If you are unsure about Zama Protocol, official repositories, or the overall architecture, read the overview first.
• If you are unsure about types or function signatures, read the API reference and treat the source installed in the current project as authoritative.
• For specific development tasks, read only the relevant pattern file instead of loading all references at once.

References

• references/overview.md: Introduces Zama Protocol, the problems solved by fhevm-solidity, the overall architecture, and official repository entry points.
• references/api.md: Lists common encrypted types, FHE APIs, ACL APIs, decryption APIs, configuration types, and debugging entry points.
• references/patterns/encryption.md: External encrypted inputs, FHE.fromExternal, and Hardhat/Foundry encrypted input testing patterns.
• references/patterns/decryption.md: User decrypt, public decrypt, on-chain signature verification, and common decryption mistakes.
• references/patterns/acl.md: allowThis, allow, allowTransient, public decrypt permissions, and multi-user permission propagation.
• references/patterns/operations.md: Arithmetic, comparisons, bit operations, type selection, scalar operations, and overflow-safe updates.
• references/patterns/branching.md: FHE.select, encrypted conditions, fixed-count loops, asynchronous public branching, and error handling.
• references/patterns/randomness.md: FHE.randE*, bounded randomness, transaction constraints, ACL, and game/lottery patterns.
• references/patterns/reorgs.md: Two-phase ACL authorization for high-value secrets and reorg risk handling.
• references/patterns/erc7984.md: Minimal integration, transfers, balance reads, and extension considerations for OpenZeppelin ERC7984 confidential tokens.

Minimal Safety Reminder

Do not treat a plain bytes32 as a verified encrypted input. Do not forget to set ACL permissions on new handles. Do not mark sensitive state as publicly decryptable just to make debugging easier.