3. Cryptography

Crypto Fundamentals — Quiz

Test your understanding of crypto fundamentals with 5 practice questions.

Practice Questions

Question 1

Which design principle states that a cryptosystem should remain secure even if its algorithm is public knowledge, relying solely on the secrecy of the key?

Question 2

Which property of a cryptographic hash function ensures that for a given input x, it is computationally infeasible to find a different input y≠x such that hash(y)=hash(x)?

Question 3

Which measure of randomness quantifies the worst-case unpredictability of a source, defined as $H_\infty(X) = -\log_2(\max_x P(X=x))$?

Question 4

A passphrase consists of four randomly chosen English words selected from a list of 2048 words. What is its entropy in bits?

Question 5

In an RSA system with primes $p=11$ and $q=13$, public exponent $e=7$, what is the private exponent $d$ such that $ed\equiv1\pmod{\phi(n)}$? Show your calculation.