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Class 11 Societal Impact: cheat sheet
CBSE Computer Science. Using technology responsibly: digital footprints, net etiquette, intellectual property and licences, cyber crime and safety, malware, e-waste and the IT Act.
Key ideas
- A digital footprint is the trail of data you leave online: active when you share it on purpose (a post, an email), passive when it is collected without your meaning to (location, cookies, IP logs).
- Netiquette: be polite, respect privacy, give credit, do not spam or type in capitals (it reads as shouting), and do not share unchecked news.
- Copyright protects creative work (books, songs, code, photos), a patent an invention, and a trademark a business’s name, logo or slogan.
- Plagiarism is presenting someone else’s work as your own; avoid it by using your own words and naming the source.
- Under the GPL changed versions must be shared under the same licence (copyleft); Apache is permissive; Creative Commons suits photos, music and writing.
- Cyber crimes include hacking, phishing, cyber bullying, trolling, identity theft and ransomware; in India they come under the Information Technology Act, 2000.
- Malware: a virus attaches to files and spreads, a trojan hides in useful-looking software, ransomware locks files for money, spyware records what you type, adware shows unwanted ads.
- E-waste (old and broken devices) holds harmful materials, so it should be reused or given to proper recyclers.
Remember
| PINs of n digits | 10ⁿ possible PINs: 4 digits → 10,000; each extra digit gives 10 times as many |
| Passwords | k characters to choose from, n places: kⁿ passwords; 26 small letters, 3 places → 17,576 |
| Time to try all | number of passwords ÷ tries per second: 10,000 PINs at 500 a second → 20 s |
| Character sets | digits 10; small letters 26; small and capital letters 52; letters and digits 62 |
| Strong password | long, mixing small and capital letters, digits and symbols; a different one for each account |
Watch out
- Calling cookies or location tracking an active footprint: data collected without your meaning to share it is passive.
- Mixing up the IPRs: an invention is patented, a logo is a trademark, a song or program is under copyright.
- Thinking a longer password from the same characters is only a little stronger: each extra character multiplies the possibilities.
Worked example
A phone is protected by a PIN of 4 digits. A program can try 500 PINs a second. (a) How many different PINs are there? (b) How many seconds would it take to try them all? (c) How many times longer would it take if the PIN had one more digit?
Working: 10 to the power 4; 10,000 ÷ 500; each extra digit gives 10 times as many PINs
Answer: (a) 10,000; (b) 20; (c) 10
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