An organisation can implement one of two encryption algorithms. Algorithm A uses a 128‑bit key and the probability that a brute‑force attack succeeds within a year is $1/2^{40}$. Algorithm B uses a 256‑bit key with success probability $1/2^{80}$. Implementation costs are £5 000 for A and £8 000 for B. The expected loss from a successful breach is £200 000. Assuming only one algorithm is used, compute the expected monetary loss (implementation cost plus expected breach loss) for each algorithm over one year, and state which algorithm minimises the expected loss.

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Algorithm A: £5,000.00; Algorithm B: £8,000.00 - Algorithm A minimises the expected loss.

Gce Model Questions Vol1 2024 Computer Studies Question 39

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