COMP6452 Flashcards
Asset Tokenisation =
representing the ownership rights of real-world assets as digital tokens on a blockchain.
Minting an NFT
publishing a unique instance of your ERC721 token on the blockchain
Ledger =
shared append-only database of blocks of TXs. It is one list, but operators are in a peer-to-peer network
What are the types of DLT Systems
permissionless, permissioned, public, private
What is the goal of a distributed ledger?
Decentralised trustless environment achieved through replication, transparency and cross checked-data. Don’t trust any individual node, but the whole network.
Full vs distributed ledger
Full means the whole ledger is replicated at all parties, while shared means parts are replicated across multiple parties.
With multiple copies of a ledger, need to
ensure it is maintained and consistent.
The double spending problem could arise if
the ledger synchronisation is built to accomodate inconsistencies.
Sender times are not reliable due to
drift and skew, and could be changed to game the system
Instead of relying on sender times, should rely on
nodes/replicas to agree on a global ordering of transactions
CAP theorem states
it is impossible for a web service to provide consistency, availability and partition-tolerance at the same time.
What is mandatory in distributed systems?
Partition tolerance
Describe the structure of a blockchain
Collection of ordered TXs from a block’s body
Summary of those TXs & hash of previous block forms a block’s header
Collection of blocks form a blockchain
- blocks are built through distributed set of nodes via mining
- nodes agree on contents of a block, order of blocks & who has the right to build a block
Describe the node network infrastructure
Peer to peer network of nodes, each with same rights to update the ledger
Each node hosts a replica of the ledger which allows high availability and efficient read access
Communicate via gossip protocol for TX propogation and consensus protocol for agreement (generally super majoritty agreemnet i.e. 2/3 is required to detemine what changes are needed)
Non functional properties of blockchains
+ Integrity, non-repudiation
+ read / - write availability
+ read / - write latency
- confidentiality
- modifiability
- throughput, scalability, big data
What roles can blockchains play in an arhcitecture?
Storage, Communication, Computation, Achritectural, and asset management and control
Replicated and distributed ledger is kind of like
a linked list with hash pointers
hashing =
converts a large volume of data into a small datum, i.e. maps arbitrary-sized data to fixed-size data
Properties of cryptographic hash functions =
deterministic
small change -> massive change in hash value
quick to compute
one-way function, cannot invert it
infeasible to hash-collision
Merkle tree =
binary tree built using hashes
Alllows efficient and secure verification of contents of large data structures
Can efficiently demonstrate a leaf node is part of a given hash tree
For BCs,
leaves of the tree are hashes of TXs
You concatenate two leaves and calculate another hash and continue this until the root of the tree is reached
Public Key Cryptography =
System that uses a public key which may be disseminated widely and a private key that is only known to the owner i.e. assymetric cryptography
What is the one base cryptocurrency that a platform has called?
Native currency
native currency can only be acquired by?
mining or purchasing from cryptocurrency exchanges
What is a 1st Gen Blockchain?
Bitcoin!
Where users create, sign and announce TXs to the netwrok
Miners then receive the TXs, include them in a new block and then try to append them to the chain of blocks. Once, the TX is part of the data structure it has officially taken place.
