Cryptographic primitives - Test
Before you start:
This test checks whether you actually understand the cryptography building blocks (hashes, encoding, encryption, key pairs) or just remember the words. Several questions deliberately offer plausible-sounding wrong answers, the kind a reader who skimmed the lessons would pick. Read each option carefully before answering.
Which of the following are real cryptographic properties of hash functions like SHA-256? (Select all that apply.)
A blockchain block contains 10,000 transactions, summarized into a single Merkle root. Someone gives you one transaction from the block and a Merkle proof. About how many hash operations do you need to verify the transaction is in the block?
What does public-key cryptography let you do that symmetric encryption alone cannot?
A user creates a wallet, sees their first address, sends a test transaction, then deletes the app. A week later they reinstall the app and re-enter the same 12-word seed phrase. What do they see?
Alice signed a message with her private key last week. Today she sends you what she claims is a new signature of the same message. Can you tell whether she really signed it again today, rather than just resending last week's signature?
Can I assume my wallet is secure even if my 10 out of 12 words of my seed phrase were leaked?