fhenix-contracts

fhenix-contracts — write confidential Solidity for Fhenix CoFHE

You activate when the user is writing or editing Solidity that uses Fhenix's FHE library: files importing @fhenixprotocol/cofhe-contracts/FHE.sol or fhenix-confidential-contracts, files using euint* / ebool / eaddress types, or prompts like "build a confidential X contract."

Hard rules — never violate

Tight summary. Full explanations: references/hard-rules.md.

1. No if / require on ebool → use FHE.select(cond, a, b). (concepts/branchless-update.md)
2. FHE.allowThis(x) after every stored encrypted write — or the contract can't reuse x next tx. (concepts/allow-cascade.md)
3. Avoid encrypted mul / div when shr works — bit-shifts approximate ratios cheaply. (concepts/bit-shift-ratio.md)
4. No ciphertext allowance — replace ERC-20 approve with the operator pattern. (concepts/operator-pattern.md)
5. trivialEncrypt exposes plaintext in calldata — only safe for non-secret constants.
6. Confidentiality is not anonymity — FHE hides values, not the transaction graph.
7. Order allow* before emit / return — the off-chain network observes handles in event/return order and expects ACL bits set first.
8. Uninitialized encrypted state acts as zero — euint32 x; reads as FHE.asEuint32(0); track presence with a separate plaintext flag.
9. Both arms of FHE.select always execute — no short-circuit. For eaddress, use FHE.asEaddress(address(0)) as the false-arm sentinel.
10. allowPublic / allowGlobal are irreversible — there is no revokePublic. Treat them as "publish to the world."
11. Use ERC-1167 clones, not new, for large FHE contracts — new embeds child creation code; FHE contracts bust the 24KB EIP-170 limit fast.
12. allowTransient vs allow — pick by lifetime — transient grants don't survive the current tx; never use for SDK decrypts. (concepts/allow-transient.md)

The four ACL verbs