Boolean Operations
Overview
Quick Start
# Create new project from this template
npx labz create boolean my-project
# Navigate and install
cd my-project
npm install
# Run tests
npx hardhat testContract
// SPDX-License-Identifier: BSD-3-Clause-Clear
pragma solidity ^0.8.24;
import { FHE, ebool, euint8, externalEbool, externalEuint8 } from "@fhevm/solidity/lib/FHE.sol";
import { ZamaEthereumConfig } from "@fhevm/solidity/config/ZamaConfig.sol";
/// @title Boolean Operations - Encrypted boolean logic
/// @notice Demonstrates ebool type and boolean FHE operations
/// @dev Shows FHE.not(), FHE.and(), FHE.or(), FHE.asEbool(), comparison to ebool
contract BooleanOps is ZamaEthereumConfig {
/// @dev Stores various boolean results
ebool private _result;
ebool private _flag;
// ============ Events ============
event BooleanSet(address indexed user);
event NotApplied(address indexed user);
event AndApplied(address indexed user);
event OrApplied(address indexed user);
event ComparisonDone(address indexed user);
// ============ Boolean Creation ============
/// @notice Set an encrypted boolean value
/// @param encryptedValue Encrypted boolean from client
/// @param inputProof Zero-knowledge proof for the input
function setBool(externalEbool encryptedValue, bytes calldata inputProof) external {
// Convert external encrypted bool to internal ebool
_flag = FHE.fromExternal(encryptedValue, inputProof);
// Set permissions
FHE.allowThis(_flag);
FHE.allow(_flag, msg.sender);
emit BooleanSet(msg.sender);
}
/// @notice Create ebool from plaintext (for initialization only!)
/// @dev WARNING: This exposes the value! Only use for known public values
/// @param value The plaintext boolean
function setPlainBool(bool value) external {
// Convert plaintext to encrypted boolean
// This is visible on-chain! Only use for initialization
_flag = FHE.asEbool(value);
FHE.allowThis(_flag);
FHE.allow(_flag, msg.sender);
emit BooleanSet(msg.sender);
}
// ============ Boolean NOT ============
/// @notice Apply NOT to the stored flag
/// @dev Flips true <-> false in encrypted form
function applyNot() external {
// NOT operation: flips the encrypted boolean
// If _flag is encrypted(true), result becomes encrypted(false)
_result = FHE.not(_flag);
FHE.allowThis(_result);
FHE.allow(_result, msg.sender);
emit NotApplied(msg.sender);
}
/// @notice Apply NOT to input and return
/// @param encryptedValue Encrypted boolean to negate
/// @param inputProof Zero-knowledge proof for the input
function notValue(externalEbool encryptedValue, bytes calldata inputProof) external returns (ebool) {
ebool input = FHE.fromExternal(encryptedValue, inputProof);
_result = FHE.not(input);
FHE.allowThis(_result);
FHE.allow(_result, msg.sender);
emit NotApplied(msg.sender);
return _result;
}
// ============ Boolean AND ============
/// @notice AND two encrypted booleans
/// @param a First encrypted boolean
/// @param b Second encrypted boolean
/// @param inputProof Zero-knowledge proof for the inputs
function andBools(externalEbool a, externalEbool b, bytes calldata inputProof) external returns (ebool) {
ebool encA = FHE.fromExternal(a, inputProof);
ebool encB = FHE.fromExternal(b, inputProof);
// AND: true only if BOTH are true
_result = FHE.and(encA, encB);
FHE.allowThis(_result);
FHE.allow(_result, msg.sender);
emit AndApplied(msg.sender);
return _result;
}
// ============ Boolean OR ============
/// @notice OR two encrypted booleans
/// @param a First encrypted boolean
/// @param b Second encrypted boolean
/// @param inputProof Zero-knowledge proof for the inputs
function orBools(externalEbool a, externalEbool b, bytes calldata inputProof) external returns (ebool) {
ebool encA = FHE.fromExternal(a, inputProof);
ebool encB = FHE.fromExternal(b, inputProof);
// OR: true if EITHER is true
_result = FHE.or(encA, encB);
FHE.allowThis(_result);
FHE.allow(_result, msg.sender);
emit OrApplied(msg.sender);
return _result;
}
// ============ Comparison to ebool ============
/// @notice Compare two encrypted integers, get ebool result
/// @dev This shows how comparisons produce ebool values
/// @param a First encrypted value
/// @param b Second encrypted value
/// @param inputProof Zero-knowledge proof for the inputs
function isGreater(
externalEuint8 a,
externalEuint8 b,
bytes calldata inputProof
) external returns (ebool) {
euint8 encA = FHE.fromExternal(a, inputProof);
euint8 encB = FHE.fromExternal(b, inputProof);
// Comparison operations return ebool
// This is useful for conditional logic
_result = FHE.gt(encA, encB);
FHE.allowThis(_result);
FHE.allow(_result, msg.sender);
emit ComparisonDone(msg.sender);
return _result;
}
/// @notice Check equality of two encrypted values
/// @param a First encrypted value
/// @param b Second encrypted value
/// @param inputProof Zero-knowledge proof for the inputs
function isEqual(
externalEuint8 a,
externalEuint8 b,
bytes calldata inputProof
) external returns (ebool) {
euint8 encA = FHE.fromExternal(a, inputProof);
euint8 encB = FHE.fromExternal(b, inputProof);
// eq() returns ebool
_result = FHE.eq(encA, encB);
FHE.allowThis(_result);
FHE.allow(_result, msg.sender);
emit ComparisonDone(msg.sender);
return _result;
}
// ============ View Functions ============
/// @notice Get the last boolean result
function getResult() external view returns (ebool) {
return _result;
}
/// @notice Get the stored flag
function getFlag() external view returns (ebool) {
return _flag;
}
}
Code Explanation
Imports
Not Operation
And Operation
Or Operation
As Ebool
Comparison To Ebool
FHE Operations Used
FHE Types Used
Tags
Related Examples
Next Steps
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