Getting Started

The Nox Solidity library lets you write smart contracts that operate on encrypted data. You import the Nox library, use encrypted types like euint256 instead of uint256, and the protocol handles encryption and off-chain computation transparently.

How It Works

Working with confidential data in Solidity follows three steps:

1. Receive encrypted inputs: the user encrypts a value with the JS SDK and sends a handle + proof to your contract. You call Nox.fromExternal() to validate the proof and get a typed encrypted handle.

2. Compute on encrypted data: use Nox.add(), Nox.sub(), Nox.eq(), Nox.select(), etc. These functions emit events that trigger off-chain TEE computation. The result is a new encrypted handle.

3. Manage access: grant permissions with Nox.allow() so handles can be reused in future transactions, and Nox.addViewer() so users can decrypt results off-chain via the JS SDK.

INFO

Operations on encrypted handles are not executed on-chain. The contract emits events, and the off-chain Runner performs the actual computation asynchronously inside a TEE enclave. The encrypted result is stored in the Handle Gateway under the deterministic handle computed on-chain.

Prerequisites

• Solidity ^0.8.0
• Hardhat 3 or Foundry
• Node.js 18+ with npm, yarn, pnpm, or bun

Installation

npm

npm install @iexec-nox/nox-protocol-contracts

yarn

yarn add @iexec-nox/nox-protocol-contracts

pnpm

pnpm add @iexec-nox/nox-protocol-contracts

bun

bun add @iexec-nox/nox-protocol-contracts

The encrypted-types package (providing euint256, ebool, etc.) is installed automatically as a dependency.

Imports

import {Nox, euint256, externalEuint256} from "@iexec-nox/nox-protocol-contracts/contracts/sdk/Nox.sol";

Import the Nox library along with the encrypted types you need, all from a single path. The Nox.sol file re-exports every type from EncryptedTypes.sol, so there is no need for a separate import.

Encrypted Types

Encrypted types are custom defined value types backed by bytes32. Each type wraps a handle, a 32-byte identifier that references encrypted data stored off-chain in the Handle Gateway.

Category	Types	Example
Boolean	ebool	Encrypted true/false
Unsigned integers	euint8, euint16, ..., euint256	Encrypted balances, amounts
Signed integers	eint8, eint16, ..., eint256	Encrypted signed values
Address	eaddress	Encrypted Ethereum address
Fixed bytes	ebytes1, ..., ebytes32	Encrypted raw bytes

Each type has a corresponding external* variant (e.g. externalEuint256) used for handles received from users that need proof validation before use.

Next Steps

• Arithmetic: add, sub, mul, div with wrapping semantics
• Comparisons: eq, ne, lt, le, gt, ge
• Token Operations: transfer, mint, burn
• Access Control: permissions and viewer management
• JS SDK: encrypt inputs and decrypt results from JavaScript