REVIEW CORRECT 100%
Impossible in blockchain - ANSWERRemove or erase data, Edit or change data
Possible in blockchain - ANSWERRetrieve or read data
Add or write date
Permissioned vs. permissionless - ANSWERPermissionless blockchain protocols
like Bitcoin and Ethereum allow everybody to participate and add blocks, whereas
only identified members can approve and add blocks in permissioned blockchains.
Problems with bitcoin - ANSWERScalability, Speed, Sustainability, Vulnerability to
Quantum computers, Lack of governance structure, Hard forks
Competitive advantages of bitcoin as first-mover - ANSWEREconomies of scale
results in higher security, Network effects
Maersk - ANSWERPaperwork had delays, errors, complications, inefficiencies and
blind spots. GTD is an industry wide blockchain platform that provides single source
of truth
Permissioned blockchain
List all of the bitcoin protocol - ANSWERAny node (miner) can add a block of
transactions to the blockchain. A transaction can offer commission to the miner who
adds it. The miner who adds the block takes its commissions. The miner also gets
additional bonus from thin air. So miners compete to add the next valid block. The
longest valid chain is the canonical chain. Balances are not stored but calculated
from previous transactions.
the canonical chain - ANSWERthe longest valid chain
Proof of Work - ANSWERThe first miner who finds the hash of block adds the block.
The hash of block should be smaller than 2N. Should have 256-N zeros at the
beginning. Each block contains a nonce. Miner should find a nonce that makes the
hash less than 2N
Hashing - ANSWERlinks blocks together
hash contains transaction information -amount, address, timestamp. can only get
one hash out of identical inputs (impossible to get identical hashes out of two
differing inputs). impossible to get two hashes out of one input
nonce - ANSWERa 32-bit (4-byte) field whose value is adjusted by miners so that
the hash of the block will be less than or equal to the current target of the network.