# Internal audit

General audit phase :
- Automatic tools scan
- [x] Slither
- [ ] Echidna(fuzz-testing)
- [ ] Slither(static analysis)
- [ ] Manticore(Symbolic execution)

- Manual Review
- Grammar bug
- Business logic bug

### Audit scope

The audit content includes :

- SMASP.sol ,
- Verifier.sol ,
- Compilance.sol,
- SVault.sol

### Basic error types
- [x] Overflow and underflow
Since solidity above 0.8.0 already has safe check for such , and Silent contract uses solidity 0.8.4 , this shall not be be an issue if the contract got compiled successfully .

In compilance.sol , we are using uint16 for index , this would introduce the risk of overflow .
- [x] Function visibility
Ensure that public , private , internal , external are correctly placed .

- [x] Avoid problematic features
- [x] send
- [x] low-level functions
call , delegatecall , callcode , inline assembly
They didn't introduce these problematic features in the audit scope files .
- [x] Access control
- [x] OnlyOwner Modifier
- [x] DAO gots the ownership of initilization of SMASP pool
- [x] PublicKey Management

- [ ] External Call
- [ ] check reentrancy

- [ ] Proper inilization of SMASP pool

- [ ] Time Manipulation

- [ ] Prevent unbounded loop

- [ ] Validate inputs of external/public functions

- [x] Return value check
#### Cmpliance.sol
The return value type of index variable in compliance.sol is uint16 , i.e. function getIndexOfPublicKey . This would somehow introduce the risk of overflow

- [x] Prevent using tx.origin as an authemtication mechanism

### Gas optimization
- [x] Follow variable packing rules
https://fravoll.github.io/solidity-patterns/tight_variable_packing.html
- [x] Avoid accessing storage data in interations
- Access data from memory , not from storage https://marduc812.com/2021/04/08/how-to-save-gas-in-your-ethereum-smart-contracts/
- [ ] Storing data that can be pre-computed off-chain

### Function modular check
- [x] Register
Note : In compilance.sol , we set the deployer as the owner of this contract . And the register function can only be called by this deployer. With this , the deployer of DAO can add group member to whitelist .
Some code are strange but correct , like

        for (uint16 i = 0; i < registeredKeys.length; i++) {
            if (registeredKeys[i][1] == yPubKey) {
                return i;
            }
        }
        return 65535;
    }```
registeredKeys are defined as an array of uint256[2] , and this function finds if there is second element of i-th slot that is equal to yPubKey .  
- [ ] Deposit 
    - [ ] the amount of funds received is correct 
    - [ ] all accounts are randomized with the same randomness 

- [ ] Withdraw 

- [ ] Secret Transfer   
### Testing and software engineering

- [ ] Test coverage 
 
- [ ] Unit Tests
- [ ] Integration Tests 
- [ ] Code Freeze