Wirelesses Local Area Networks (WLANs) have become more prevalent and are widely deployed and used in many popular places like university campuses, airports, residences, cafes etc. With this growing popularity, the security of wireless network is also very important. In this work, the evaluation of CRC-32 and SHA-1 is performed by calculating the throughput and by running dictionary attack on both the algorithms. The analysis shows that SHA-1 is more secure that CRC-32.