Teaching article
A symbol message is readable only with its key
Distinguish the message from the shared mapping used to read it.
A star can stand for a particular letter under one invented mapping and something else under another. Keep the key beside the message so disagreement about decoding can be traced to the agreed convention.
A star mapped to A means A only under this key.
Check the mapping before the message
- Read the mapping.
- Decode a short message.
- Check by re-encoding.
Keep the key beside the message during the first attempt. A disagreement about the mapping should be resolved before interpreting the output.
Did both readers use the same key? Use three symbols first.
This classroom substitution is not secure encryption.
Resources
- Human Robot Commands – Coding Without Screens Printable Game — Check the command conventions before using the sequence or debugging task.
Further reading
- CS Unplugged — Kidbots and algorithm activities
- Australian Curriculum Version 9 — Technologies overview
Read next
- Picture codes represent selected information
- A repeat-until process needs a reachable stop condition
- An event starts an agreed response
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