Neco 2022 Computer Studies Question 24

An organisation faces an annual data‑breach probability of 0.12. External attacks account for 70\% of breaches and internal threats for 30\%. Two security measures are considered (only one can be implemented): (i) AES‑128 encryption reduces the probability of a breach caused by cryptographic attack to 0.02 per year, with other causes unchanged; (ii) a firewall blocks 95\% of external attacks, leaving internal threats unchanged. Assuming the entire external breach probability is due to cryptographic attack, compute (a) the annual breach probability if AES‑128 is implemented, (b) the annual breach probability if the firewall is implemented, and (c) which measure yields the lower breach probability. Give answers rounded to four decimal places.