| Date | November 2020 | Marks available | 2 | Reference code | 20N.3.HL.TZ0.1 |
| Level | HL | Paper | 3 | Time zone | no time zone |
| Command term | Identify | Question number | 1 | Adapted from | N/A |
Question
Refer to the Paper 3 Case study: a local economy driven by blockchain, available under the "Your tests" tab > supplemental materials.
Identify two characteristics of a peer-2-peer (P2P) network.
Identify two sources of entropy.
Markscheme
Award [2 max].
Many clients connect directly to many other clients;
Clients also act as servers;
No centralized administration for the network/decentralized network;
Network is more resilient to failure;
Is more scalable than a client server network;
There are no "bottlenecks" as with Client Server model;
Note: Do not accept “widely used for illegal file sharing” (or similar).
Award [2 max].
Answers may include:
atmospheric noise;
radioactivity;
thermodynamics;
Brownian motion of particles;
mouse movements;
algorithmic sources;
Note: Do not accept “Entropy can be obtained from physical sources” as this is clearly stated in the case study. A physical source must be stated (e.g. radioactivity) to get that mark.
