11.1 Beyond public blockchains

Question 1

Public blockchain:
The network has … for anyone who wants to participate.
Examples:
Ethereum, Monero, Bitcoin, Litecoin

vs

Private blockchain:
Read and write access to the network is limited to a …. These networks are (so far) also always permissioned. Therefore, private blockchains usually achieve a much higher … compared to public chains. Private blockchains are a very centralized approach to blockchains and use cases have yet to be found where such solutions are superior to conventional systems.

Examples:
Monax, MultiChain, C-Chain, Quorum

Answer 1

open read and write access

certain set of entities; throughput rate ;

Question 2

Permissionless blockchain:
The network is completely open for anyone who wants to participate in … Currently, a highly used Sybil control mechanism is …. Network participants are usually financially incentivized by … (e.g., Ether or Bitcoin).
Examples:
Ethereum, Monero, Bitcoin, Litecoin

vs

Permissioned/consortium blockchain:
Participation in the consensus mechanism is restricted to a certain set of entities. This allows the use of … (e.g., Proof of Authority). Therefore, permissioned blockchains usually achieve a much … compared to permissionless chains.
Examples:
Ripple, Hyperledger Fabric

Answer 2

reaching consensus; Proof-of-Work (PoW); a native currency

more centralized Sybil control mechanisms; higher throughput rate

Question 3

Motivation for Permissioned Blockchains
The problem: …
Challenges:
Having a cost effective and secure data structure.
§ Who owns and operates the ledger?
§ Who pays for the shared data structure?
§ What are allowed operations on the shared
data structure?
§ What is the process of adding new
parties?
§ How is consensus achieved?

Answer 3

Multiple parties that do not fully trust each other need to share information in a tamper proof and secure way.

Question 4

Business Requirements for Blockchain-based Systems
Privacy: The network must be secured via … Only involved parties should be able to issue transactions and participate in the network.

Smart contracts: The platform should support the … on which the participating parties have agreed on.

Answer 4

authentication and authorization mechanisms;

execution of business logic

Question 5

Business Requirements for Blockchain-based Systems
Trust: All transactions that are issued on the network must be… to a set of rules on which the participating parties agreed on.

Single source of truth: An immutable ledger that …. Participating parties must be accountable for … on the network.

Answer 5

verified and valid

keeps track of all transactions; transactions they issue