Blockchain Flashcards
What’s the difference between centralized and decentralized systems?
- Centralized systems have single PoF, lacks scalability and have higher costs.
- Decentralized systems do not have single PoF, have better scalability and reduced costs.
Why is a decentralized ledger better?
No designated centralized authority gets to decide on anything, consensus is determined by a large amount of people instead as we distribute trust.
What is a bolckchain?
Chain of blocks (linked list) that contain information on validated transactions that prevents unauthorized data changes.
What is proof of work?
Proof of work is a computational problem that takes considerable effort to solve, but time to verify is way less.
If an attacker tampers with a block and broadcasts it, they will also require a lot of effort to recalculate all PoW for following blocks.
What is the PoW consensus model?
PoW is a consensus algorithm used to confirm transactions and generate new blocks to be added to a chain.
What are merkle trees?
Merkle trees are used to efficiently store large data structures, such as blockchain transactions.
What are the advantages of merkle tree?
- Easy to check
- Use less resources
- Easy to verify
What are some blockchain vulnerabilities?
- 51% attack
- Double Spend attack
- DDoS attacks
How do you mitigate a 51% attack?
Penalize privately mined blocks with a block acceptance delay in relation to the amount of time the block has been hidden.
How do you mitigate a double spend attack?
Use a shard / layer2 chain like Komodo that provides an anchor to which a blockchain can reference the last legal block in case of an attack.
How do you mitigate a DDoS attack?
- Rent decentralized data
- Use protection pools filled with unused bandwidth
- Block specific IPv4/v6 addresses.
