← ACARA Digital Technologies Years 5–6

Building a passphrase from random words

To build a passphrase, pick three or four random words that do not belong together and join them. Adding a number or symbol between the words makes it even harder to guess.

Part of: ACARA Digital Technologies Years 5–6 — Staying Safe Online — Module 9

Understanding Building a passphrase from random words in ACARA Digital Technologies Years 5–6

What it does: Banana, rocket and sock have nothing to do with each other, which makes the passphrase hard to guess. Using four short random words gives a longer passphrase that is still easy to type and remember. Picking words from around you at random works well. Words about you are easier for other people to guess. A number or symbol between the words adds extra surprise. Joining words in a neat, simple order does not. The colours belong together as a group, so they are easier to guess. kite, spoon, rain and bus do not belong together. The three words are unrelated and the plus symbols join them, so it is hard for others to guess.

Common mistakes: "fork" belongs with "spoon", so the words are related and easier to guess. Pick random words that do not belong together, like "sock". A passphrase needs three or four random words. One word is too easy to guess, so count should be 3 or 4.

Class: _____________________  ·  Name: _____________________  ·  Date: _________

Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

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This module's key terms are also in a printable crossword (Modules 137–153) and word search (Modules 137–225).

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Each concept is reinforced from every angle — learned, then applied, then tested.

Learning
Duo
Which is a better way to build a passphrase?
Pick three or four random words that do not belong togetherPick one word that you really love
Matches
ilovemydog
↓
The words make a sentence about you, so people who know you could guess it. Use random words that do not belong together.
Applying
Meanings
Term
random words
Meaning
To build a passphrase, pick three or four random words that do not belong together and join them. Adding a number or symbol between the words makes it even harder to guess.
Practice
word1: lamp
Testing
Gaps
passphrase ← word1 word2 + word3
Check Answer
Spots
2word2 ← "volcano"
3word3 ← "fork"

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Quick Questions

1. Which is a better way to build a passphrase?
A. Pick three or four random words that do not belong together ✓
B. Pick one word that you really love
A passphrase works best when the words are random and do not belong together. That makes it very hard to guess.
2. Which passphrase is built from random words?
A. my-dog-is-Max
B. lamp-frog-cloud-7 ✓
lamp, frog and cloud have nothing to do with each other. 'my dog is Max' is a sentence about you, so people could guess it.
3. Where can you find random words to use in a passphrase?
A. Use your name, your pet's name and your school
B. Look around the room and pick things you can see, like desk, sock and window ✓
Picking words from around you at random works well. Words about you are easier for other people to guess.
4. Which is true about the words in a passphrase?
A. Four short words are better than one long word ✓
B. One long word is always better than four short words
Joining several random short words makes a longer passphrase that is harder to guess than a single word.
5. How can you make a passphrase even harder to guess?
A. Add a number or symbol between the words, like boat7pizza!tree ✓
B. Put the words in alphabetical order with no gaps
A number or symbol between the words adds extra surprise. Joining words in a neat, simple order does not.

Match the Pairs

teapot-87-cloud-sock → A passphrase of four random words joined with a number and a symbol
pencil+zebra+moon → A passphrase of three random words joined with plus symbols
Pick words that do not belong together, like things you spot around the room → banana-rocket-sock
Four short words joined together are better than one long word → dog+sky+jam+owl
ilovemydog → The words make a sentence about you, so people who know you could guess it. Use random words that do not belong together.
sun-moon-star-sky → All the words belong to the same topic, so they are easy to guess. Pick words that are not related.

Key Term

random words
To build a passphrase, pick three or four random words that do not belong together and join them. Adding a number or symbol between the words makes it even harder to guess.

Fill in the Blanks

1. passphrase ← word1 + word2 + word3
Hint: Type the operator that joins the words together into one passphrase.
2. phrase ← word1 + "-" + word2 + "-" + word3
Hint: Type the name of the first word variable, following the pattern of the other two.
3. words ← ["tiger", "pencil", "cloud"] word1 ← RANDOM(words)
Hint: Type the function name that picks one word from the list by chance.
4. wordCount ← 4 IF wordCount >= 3 THEN PRINT "Good passphrase"
Hint: Type the comparison operator that checks there are at least three words.
5. symbol ← "#" passphrase ← word1 + symbol + word2
Hint: Type the variable name that holds the character placed between the two words.

Spot the Error

Question 1
A word1 ← "spoon"
B word2 ← "volcano"
C word3 ← "fork"
D pw ← word1 + word2 + word3
Line C — "fork" belongs with "spoon", so the words are related and easier to guess. Pick random words that do not belong together, like "sock".
Question 2
A words ← ["pan","owl","sand"]
B count ← 1
C pw ← join(words, "-")
D show pw
Line B — A passphrase needs three or four random words. One word is too easy to guess, so count should be 3 or 4.
Question 3
A w1 ← "frog"
B w2 ← "lamp"
C w3 ← "bus"
D pw ← w1 + "7" + w2
Line D — This only joins two words and leaves out w3. Join three words, putting a number or symbol between them: w1 + "7" + w2 + "!" + w3.
Question 4
A words ← [myName, myPet]
B pw ← join(words, "-")
C show pw
Line A — Your name and pet are personal and easy for others to guess. The words should be random, so it should be words ← random(4).
Question 5
A words ← ["cat","mug","sun"]
B count ← length(words)
C if count > 3 then pick more
D join words with "-"
Line C — The check is the wrong way round. You need to pick more words when count is LESS than 3, so use < not >.

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