Security

The following documentation provides context, reasoning, and examples of modules found in the Security directory.

Initializable

The Initializable module provides a simple mechanism that mimics the functionality of a constructor. More specifically, it enables logic to be performed once and only once which is useful to set up a contract’s initial state when a constructor cannot be used, for example when there are circular dependencies at construction time.

Many modules also use the initializable pattern which ensures that implementing contracts:

Don’t allow circuit calls until the contract is initialized.
Can only initialize the contract once.

Usage

// CustomContractStateSetup.compact

pragma language_version >= 0.16.0;

import CompactStandardLibrary;
import './node_modules/@openzeppelin-compact/contracts/src/security/Initializable';

export ledger _fieldAfterDeployment: Field;

export circuit doSomethingBeforeInitialized(): [] {
  // Ensure action can only be done prior to custom initialization
  Initializable_assertNotInitialized();
  // Do the thing
}

export circuit setFieldAfterDeployment(f: Field): [] {
  // Initialize so the circuit cannot be called again
  Initializable_initialize();
  _fieldAfterDeployment = f;
}

export circuit checkFieldAfterDeployment(): Field {
  // Can only be called after the contract is initialized
  Initializable_assertInitialized();
  return _fieldAfterDeployment;
}

Pausable

The Pausable module allows contracts to implement an emergency stop mechanism. This can be useful for scenarios such as preventing trades until the end of an evaluation period or having an emergency switch to freeze all transactions in the event of a large bug.

To become pausable, the contract should include pause and unpause circuits (which should be protected). For circuits that should be available only when paused or not, insert calls to assertPaused and assertNotPaused respectively.

Usage

For example (using the Ownable module for access control):

// OwnablePausable.compact

pragma language_version >= 0.16.0;

import CompactStandardLibrary;
import './node_modules/@openzeppelin-compact/contracts/src/security/Initializable' prefix Initializable_;
import './node_modules/@openzeppelin-compact/contracts/src/access/Ownable' prefix Ownable_;

constructor(initOwner: Either<ZswapCoinPublicKey, ContractAddress>) {
  Ownable_initialize(initOwner);
}

export circuit pause(): [] {
  Ownable_assertOnlyOwner();
  Pausable__pause();
}

export circuit unpause(): [] {
  Ownable_assertOnlyOwner();
  Pausable__unpause();
}

export circuit whenNotPaused(): [] {
  Pausable_assertNotPaused();
  // Do something
}

export circuit whenPaused(): [] {
  Pausable_assertPaused();
  // Do something
}