1. Humans can leave traces of information with the use of technologies simply by browsing the web, using a credit or debit card, tagging friends in personal posts via online apps, adding locations on photos or comments etc or connecting to wireless internet.
2. These are some of History’s famous codes: ROT1, Transposition, Caesar shift cipher, public-key cryptography, monoalphabetic substitution and true-codes. To inspire and support a lesson about encoding and decoding messages you could implement a word finder puzzle with having the key words create an important message about the encoding and decoding topic.
3. This teaching approach can be useful to incorporate into a lesson plan for primary students as it discusses valuable information regarding sharing information and what is safe communication in an online environment.

https://www.esafety.gov.au/educators/classroom-resources/hectors-world/your-personal-information-online