AP CSP Mock Test - ReviewAP CSP Mock Test Review: Key points

1. Knowledge Points

(2) 5.4 Crowdsourcing (Citizen science)

Crowdsourcing is the practice of obtaining input or information from a large number of people via the Internet.
Solve a problem or conduct a research with the help of the public.
Situations for using a citizen science project (crowdsourcing).
- Need more devices, people, locations, resources...to remove barriers(locations) or limits (time, resources) on the same.

(7) 3.16 Simulations

Simulations often mimic real-world events with the purpose of drawing inferences, allowing investigation of a phenomenon without the constraints of the real world. (Ex. flight simulation)
The process of developing an abstract simulation involves removing specific details or simplifying functionality.
Generally, a simulation based on a less detailed model will require less time to run.
Simulations can contain bias derived from the choices of real-world elements that were included or excluded.
Simulations are most useful when real-world events are impractical for experiments (e.g., too big, too small, too fast, too slow, too expensive, or too dangerous).
A simulation is unlikely to be appropriate if continuous real-world data is needed.
Random number generators can be used to simulate the variability that exists in the real world.
Note
- Need real data. (simulations not appropriate).
- Impractical scenarios/events. (simulations necessary).

(9) 5.6 Safe Computing

（1）Protect intellectual property
- legal ways to use material created by someone else include:
  - (1) Creative Commons (创作共享) — a public copyright license that enables the free distribution of an otherwise copyrighted work. Creative Commons licensing allows copyright owners to specify the ways in which their works can be used or distributed.
  - (2) Open source (开源) — programs that are made freely available and may be redistributed and modified. Open-source software has source code that is released under a license that allows users to use and distribute it.
  - (3) Open access (开放获取) — online research output free of restrictions on access and use, such as copyright or license restrictions. 开放获取是国际学术界、出版界、图书情报界为了推动科研成果利用互联网自由传播而采取的行动。
- rights-reversed vs. no-rights-reserved.
- single-user-license.
（2）Strong password vs. weak password
- A strong password is something that is easy for a user to remember but would be difficult for someone else to guess based on knowledge of that user.
（3）Multifactor authentication（多重验证） : use at least two authentication mechanisms.
- knowledge (something they know, password)
- possession (something they have, keys)
- inherence/ biometric (something they are, fingerprints).
（4）Encryption vs. decryption
- Encryption (加密) is the process of encoding(编码) data to prevent unauthorized access. Example: 123421 -> !@#$@!
- Decryption (解密) is the process of decoding(解码) the data. Example: !@#$@! -> 123412
- Two common encryption approaches are:
  - Symmetric key encryption (对称密钥加密) involves one key for both encryption and decryption. (keep the key secret)
  - Public key encryption (Asymmetric key encryption 非对称加密/公钥加密) pairs a public key for encryption and a private key for decryption. 公钥用于加密数据，可公开分发；私钥用于解密或签名，需严格保密。
（5）Ditital certificate
- Certificate authorities (认证中心) issue digital certificates that validate the ownership of encryption keys used in secure.
（6）Security threats:
- Computer virus: is a malicious program that can copy itself and gain access to a computer in an unauthorized way.
- Malware: is software intended to damage a computing system or to take partial control over its operation.
- Phishing: is a technique that attempts to trick a user into providing personal information. (Ex. emails)
- Keylogging: is the use of a program to record every keystroke made by a computer user in order to gain fraudulent access to passwords and other confidential information.
- Rogue access point(非法接入点): is a wireless access point that gives unauthorized access to secure networks.
- Malicious link: can be disguised on a web page or in an email message.
- Unsolicited emails(垃圾邮件): spam emails.
（7）Other Concepts
- Cookie: A cookie is a small piece of data a server sends to a user's web browser, a cookie is stored at the client side. A group of cookies can be used to track users and collect information.
- Session(会话): An HTTP session is a temporary exchange of information between a client and a server, consisting of a sequence of request–response transactions.
- Browser: Safari, Google Chrome.

(25) 4.1 The Internet

(1) The Internet vs. WWW
- The Internet is a computer network consisting of interconnected networks that use standardized, open (nonproprietary-非专属) communication protocols.
  - A protocol is an agreed-upon set of rules that specify the behavior of a system.
  - The Internet uses open standards and protocols.
  - Open protocols provide a standard way for data transmission between devices.
- The World Wide Web(WWW-万维网) is a system of linked pages, programs, and files that is accessed using the Internet.
- The WWW uses the Internet.
(2) Routing
- Routing(路由) is the process of finding a path from sender to receiver.
- Redudant routing: provide alternative path for connection failures.
(3) Bandwidth
- The bandwidth(带宽) of a computer network is the maximum amount of data that can be sent in a fixed amount of time.
- Measured in bits per second (bit/s).

(27) Undecidable problem

For undecidable problems: There exist problems that no algorithm will ever be able to solve for all possible inputs.
计算机不是万能的，总有它无法解决的问题。

(31) 5.5 Legal and Ethical Concerns

Peer-to-peer network (P2P network): In a P2P network, computers directly connect and share resources without a central server. It has a decentralized network architecture.