avoiding_common_attacks.md

- Race Conditions - Reentrancy

use send() instead of call.value()

- Cross-function Race Conditions

use internal function appropriately

- Integer Overflow and Underflow

use SafeMath library to avoid overflow and underflow

- Forcibly Sending Ether to a Contract

this smart project can receive any amount ether any time

- Transaction-Ordering Dependence (TOD)

program logic does not affected by transactions order

- Timestamp Dependence

program logic does not depende on block timestamp

- DoS with (Unexpected) revert

no refund situation, so no DoS with unexpected revert

- DoS with Block Gas Limit

no unknown size loop