Access Control

Capability-based access control for Ethereum smart contracts.

Get started

1. npm install --save @daostack/access_control

2. Use it in your smart contract

   import "@daostack/access_control/contracts/Permissioned.sol";
   
   contract Foo is Permissioned {
       // Foo stuff...
   }

Check out the documentation for more!

Concept

The basic idea is that there are a set of "locks"/"topics" each with a set of "keys". A contract can protects one of it's methods with a lock (or more) such that anyone with the appropriate key can use it to access this method. Each key can have a start time, expiration time, number of uses. Accounts can also transfer some (or all) of their capabilities to other accounts if allowed. Initially the contract itself has a "master key" (infinite uses, no expiration, no start time limitation), and then it can pass some partial capabilities to the desired accounts.

Features:

• Can define a number of uses & expiration date & start time on keys and if to enable the key to be transfrred.
• Accounts can assign partial (or full) abillites to other accounts (if allowed).
• We can use advanced lock ids to lock a method even on specific parameters, enforce ordering, or other properties (see example).
• Can define complex boolean predicates to protect methods.
• No performance loss over hand-crafted mechanisms.

Benefits:

• Declarative policy (no more sprinkling ifs all over the codebase)
• Easy control flow (ordering, timing, number of function calls) restrictions (e.g. only allowed to call B after calling A twice within 2 days).
• Allows accounts to call functions themselves instead of delegating through other contracts.
• Generalized logging mechanism: key usage events can be queried by clients to know whether a method was called and by which account, key revocations can be used to know when users no longer have access to a method.
• Easier security since we need to verify less code.

Contribute

1. git clone [email protected]:daostack/access_control.git && cd access_control
2. npm install / yarn

Available Commands:

• npm run ganache
• npm run lint
• npm run test
• npm run build
• npm run docs:<update|build|deploy|preview>