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There used to be a dilemma in blockchain: keep your application and user data on-chain, allowing everyone to see it, or keep it privately off-chain and lose contract composability. Thanks to a breakthrough in homomorphic encryption, Zama’s fhEVM makes it possible to run confidential smart contracts on encrypted data, guaranteeing both confidentiality and composability.
- End-to-end encryption of transactions and state
- Composability and data availability on-chain
- No impact on existing dapps and state
Solidity Integration: fhEVM contracts are simple solidity contracts that are built using traditional solidity toolchains.
Simple DevX: Developers can use the euint data types to mark which part of their contracts should be private.
SC-defined ACL: All the logic for access control of encrypted states is defined by developers in their smart contracts.
You can take a look at our examples!
- High Precision Integers - Up to 256 bits of precision for integers
- Full range of Operators - All typical operators are available: ,-,*,/,<,>.==,...
- Encrypted If-Else Conditionals - Check conditions on encrypted states
- On-chain Secure Randomness - Generate randomness without using oracles
- Configurable Decryption - Threshold, centralized or KMS decryption
- Unbounded Compute Depth - Unlimited consecutive FHE operations
# Using npm
npm install fhevm
# Using Yarn
yarn add fhevm
# Using pnpm
pnpm add fhevm
// SPDX-License-Identifier: BSD-3-Clause-Clear
pragma solidity >=0.8.13 <0.8.20;
import "fhevm/lib/TFHE.sol";
contract Counter {
euint32 counter;
function add(bytes calldata encryptedValue) public {
euint32 value = TFHE.asEuint32(encryptedValue);
counter = TFHE.add(counter, value);
}
function getCounter(bytes32 publicKey) returns (bytes memory) {
return TFHE.reencrypt(counter, publicKey);
}
}
See our documentation on https://docs.zama.ai/fhevm/solidity/getting_started for more details.
Install dependencies (Solidity libraries and dev tools)
npm install
Note: Solidity files are formatted with prettier.
npm run codegen
WARNING: Use this command to generate Solidity code and prettier result automatically!
Files that are generated now (can be seen inside codegen/main.ts
)
lib/Common.sol
lib/Precompiles.sol
lib/Impl.sol
lib/TFHE.sol
contracts/tests/TFHETestSuiteX.sol
test/tfheOperations/tfheOperations.ts
The easiest way to understand how to write/dev smart contract and interact with them using fhevmjs is to read and explore the few tests available in this repository.
Fast start
# in one terminal
npm run fhevm:start
# in another terminal
npm i
cp .env.example .env
./scripts/faucet.sh
npm test
We provide a docker image to spin up a fhEVM node for local development.
npm run fhevm:start
# stop
npm run fhevm:stop
To use a ready to use test (only for dev) wallet first, prepare the .env file that contains the mnemonic.
cp .env.example .env
This allows the developer to use a few accounts, each account can get coins:
npm run fhevm:faucet:alice
npm run fhevm:faucet:bob
npm run fhevm:faucet:carol
npm test
Error: insufficient funds
Ensure the faucet command is succesfull.
Operators can be defined as data inside codegen/common.ts
file and code automatically generates solidity overloads.
Test for overloads must be added (or the build doesn't pass) inside codegen/overloadsTests.ts
file.
There are two ways to contribute to the Zama fhEVM:
- you can open issues to report bugs or typos, or to suggest new ideas
- you can ask to become an official contributor by emailing [email protected]. (becoming an approved contributor involves signing our Contributor License Agreement (CLA)) Only approved contributors can send pull requests, so please make sure to get in touch before you do!
This library uses several dependencies and we would like to thank the contributors of those libraries.
This software is distributed under the BSD-3-Clause-Clear license. If you have any questions,
please contact us at [email protected]
.