Suppose that h is a secure hash that generates an n-bit hash value. (a) (5pt) Suppose...

     

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Suppose that h is a secure hash that generates an n-bit hash value. (a) (5pt) Suppose you can generate 2k hashes in one second, what is the expected time to find the one collision? (b) (5pt) What is the expected number of hashes that must be computed to find 5 collisions? That is, what is the expected number of hashes that must be computed to find pairs (xi, zi) with h(x₁) = h(zi), for i = 0,1,2,3,4,5? (c) (5pt) Following the same setting, suppose n = 256, k 128, m = 10, how much time do you need to find m collisions, using a machine that can generate 2k hashes in one second. Suppose that h is a secure hash that generates an n-bit hash value. (a) (5pt) Suppose you can generate 2k hashes in one second, what is the expected time to find the one collision? (b) (5pt) What is the expected number of hashes that must be computed to find 5 collisions? That is, what is the expected number of hashes that must be computed to find pairs (xi, zi) with h(x₁) = h(zi), for i = 0,1,2,3,4,5? (c) (5pt) Following the same setting, suppose n = 256, k 128, m = 10, how much time do you need to find m collisions, using a machine that can generate 2k hashes in one second.

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a The expected time to find one collision is given by the birthday problem formu... View the full answer