Knowledge check

Hash functions & digital signatures

10 questions testing what you just read — no login, no tracking, just immediate feedback.

Question 1 of 10

What causes a length-extension attack against SHA-2?

Question 2 of 10

Why does HMAC resist length-extension attacks that naive H(key‖message) doesn't?

Question 3 of 10

Why is SHA-256 described as offering ~128-bit, not 256-bit, collision resistance?

Question 4 of 10

What are the three core properties of a cryptographic hash function?

Question 5 of 10

Which older hash algorithms are cryptographically broken for collision resistance and shouldn't be used for security purposes today?

Question 6 of 10

What does the avalanche effect demonstrated by SHA-256("hello") vs. SHA-256("hellp") show?

Question 7 of 10

What does the Merkle-Damgård construction do with a long message before hashing it?

Question 8 of 10

What structural feature makes SHA-3 naturally immune to length-extension attacks, unlike SHA-2?

Question 9 of 10

In the "hash-then-sign" pattern used by RSA and ECDSA signatures, what does the signer actually sign?

Question 10 of 10

In HMAC's formula H((K′⊕opad) ‖ H((K′⊕ipad) ‖ m)), what are K′, opad, and ipad?

0 / 10 answered