Fundamentals of Blockchain Security Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fundamentals of Blockchain Security flashcards as text
What is the primary security purpose of a cryptographic hash function in a blockchain?
Answer: To produce a fixed-length, tamper-evident fingerprint of block data
Hash functions create a deterministic, fixed-length fingerprint so any change to block data is immediately detectable.
How does each block in a blockchain link to the previous one?
Answer: By storing the previous block's hash in its header
Each block stores the previous block's hash, creating an immutable chain where altering one block breaks all subsequent links.
Which property ensures that a blockchain transaction cannot be denied by its sender?
Answer: Non-repudiation via digital signatures
Digital signatures prove the sender authorized the transaction, providing non-repudiation.
What does a 51% attack allow a malicious actor to do?
Answer: Control consensus to double-spend or reorganize the chain
Controlling a majority of hashing or staking power lets an attacker rewrite recent history and double-spend.
Why is a private key the most critical secret in blockchain security?
Answer: It authorizes spending and proves ownership of funds
Whoever holds the private key can sign transactions and control the associated assets.
What is the security advantage of decentralization in a blockchain network?
Answer: It removes a single point of failure or control
Distributing the ledger across many nodes means no single party can be compromised to control or halt the network.
Which statement best describes blockchain immutability?
Answer: Confirmed records are practically impossible to alter without detection
Immutability means confirmed entries cannot be changed without redoing all subsequent proof-of-work and being detected.