A03: Crypto Treasure Hunt - Instructor Guide

Purpose: Complete setup and facilitation guide for running the treasure hunt activity

Pre-Class Preparation (30 minutes)

Setup Checklist

Print puzzle sheets (Easy/Medium/Hard) - one per team
Print verification worksheets - one per team
Print or create physical clue cards with signature data
Print answer key for reference
Print rubric for grading
Prepare hiding locations (see Location Ideas below)
Set up clue cards at designated locations
Test one complete puzzle yourself to verify timing
Prepare hint cards (optional, for struggling teams)
Set up presentation timer/space

Materials Needed

Per Team (3-4 students)

1 puzzle sheet (difficulty assigned)
1 verification worksheet
2-3 sheets of scratch paper
Calculator (or allow phone use)
Pens/pencils

Instructor Materials

Answer key (printed, keep secure)
Grading rubric (1 per team)
Timer or stopwatch
Physical clue cards (1 per team, pre-placed)
ASCII table printouts (optional, for student reference)
Hint cards (prepared but only distributed if needed)

Classroom Setup

Team workspaces (desks grouped for 3-4 students)
Presentation area (front of class)
Hidden clue locations (various, see suggestions below)
Whiteboard/projector for timing and announcements

Location Ideas for Hiding Clues

Safe Hiding Spots in Classroom

Location Type	Specific Examples	Difficulty Match
Book-based	- Inside specific textbook on shelf - Under book titled "Cryptoeconomics" - Behind row of books (specific color/author)	Easy, Medium
Furniture	- Under instructor's desk - Taped under specific student chair - Behind filing cabinet - Beneath the radiator/heater	Easy, Hard
Wall features	- Behind whiteboard (if removable) - Behind poster/bulletin board - In corner where two walls meet - Behind door when opened	Medium, Hard
Equipment	- Inside projector case - Behind computer monitor - In drawer labeled with specific color - Inside emergency kit box	Medium
Creative	- Inside fake book (hollowed out) - Behind clock on wall - In potted plant (sealed in plastic) - Taped to ceiling tile (reachable)	Hard

💡 Adaptation Tips:

Adjust locations based on your specific classroom layout
Ensure all locations are accessible without climbing or unsafe actions
Use different colors of clue cards for different teams to avoid confusion
Take photos of hiding spots before class for your reference

Creating Physical Clue Cards

Clue Card Template

Print on cardstock or sturdy paper. Include:

                    🔐 CRYPTO TREASURE HUNT CLUE 🔐
                
Message: KEY42
Public Key: e = 7, n = 143
Signature: S = 42

                    Verify this signature to complete your mission!

                    Team Color: GREEN

Recommendations:

Use different messages/signatures for each team to prevent copying
Laminate cards if you plan to reuse them
Color-code cards by team (use colored paper or markers)
Keep duplicate backup cards in case one is lost

Class Timeline (50 minutes)

Time	Phase	Instructor Actions
0:00-0:05	Introduction	- Welcome and form teams (3-4 students) - Explain activity overview and objectives - Distribute materials (puzzle + worksheet) - Assign difficulty levels to teams - Answer initial questions
0:05-0:20	Decryption Phase	- Start timer, teams begin decrypting - Circulate to observe progress - Provide hints if teams stuck >5 minutes - Monitor for teams finishing early - Ensure work is documented
0:20-0:30	Retrieval Phase	- Teams retrieve physical clues - Monitor to prevent one team finding another's clue - Assist teams having trouble locating (after 5 min) - Ensure clues returned to desks - Check that correct team got correct clue
0:30-0:45	Verification Phase	- Teams complete verification worksheet - Circulate to check calculations - Provide calculator/ASCII table if needed - Help with modulo operations if struggling - Monitor reflection question completion
0:45-0:50	Presentations	- Each team presents (2 min each, ~3 teams typical) - Time presentations strictly - Ask follow-up questions - Note participation for grading - Collect all materials

⚠️ Timing Warning: This is an aggressive 50-minute timeline. If your class period is 75 minutes, expand phases proportionally (especially Verification to 25 minutes). For 90-minute classes, add a debrief discussion at the end.

Facilitation Strategy

Phase 1: Introduction (5 minutes)

Script suggestion:

"Today you're crypto security auditors. You'll decrypt messages, find hidden clues, and verify cryptographic signatures—just like real blockchain validators do every day. This isn't just a game; these are the actual techniques that secure billions of dollars in cryptocurrency."

Key points to emphasize:

This is collaborative but competitive (fastest correct team wins recognition)
Show all work for partial credit
Ask for hints after 5 minutes of being stuck (don't waste time)
All team members must participate in presentation

Phase 2: Decryption (15 minutes)

Circulating observations:

Are teams dividing roles? (Decoder, checker, writer)
Are they showing systematic work or guessing?
Do they understand the cipher method?

Common struggles and hints:

Struggle	Hint to Provide
Can't find pattern in Easy puzzle	"What letter appears most often? That's probably E or T."
Confused by ROT13 in Medium	"Try shifting every letter by the same amount. What shift turns G into T?"
Lost in Hard puzzle layers	"Start with frequency analysis on the first message. Which three-letter word appears most?"
Wrong keyword alphabet	"Remove duplicate letters from your keyword first, then add remaining alphabet."

Phase 3: Retrieval (10 minutes)

Management strategies:

Prevent chaos: Only allow 1-2 team members to search at a time
Color coding: "You're looking for a GREEN card" prevents mix-ups
5-minute rule: If team can't find clue after 5 min, verify their decryption is correct, then give area hint
Security: Watch that teams don't accidentally reveal locations to other teams

If clue is missing/lost: Have backup clue cards ready. Quickly place a replacement and guide team to it.

Phase 4: Verification (15 minutes)

This is the most important learning phase. Monitor carefully.

Key checkpoints:

ASCII values: Students may not know how to find them. Have an ASCII table handout ready.
Large exponents: Most calculators can handle S^e, but show students the x^y button if needed.
Modulo operation: Many students struggle here. Explain: "Divide the big number by n, the remainder is your answer."
Comparison: Students should check if H = V. If not equal, they likely made a calculation error—help them find it.

Intervention moments:

If team is stuck on one step for >3 minutes, approach and guide (don't solve for them)
If calculation errors are cascading, help them restart from the error point
Check reflection questions—push for deeper thinking if answers are superficial

Phase 5: Presentations (5 minutes)

Structure each presentation:

Team introduces members and difficulty level (15 seconds)
Decryption method explained (45 seconds)
Verification result and key learning (45 seconds)
Quick Q&A or instructor comment (15 seconds)

Questions to ask teams:

"What was the hardest part of this activity?"
"How would changing the public key affect verification?"
"Where else have you seen signatures used in real life?"

Recognition: Announce fastest team, most creative solution, best explanation, etc.

Difficulty Assignment Strategy

Difficulty	Assign To	Expected Completion Time
Easy	Teams with less math confidence or weaker performance on prior assignments	12-15 minutes (decryption)
Medium	Average-performing teams, balanced skill levels	15-18 minutes (decryption)
Hard	High-performing teams, students with cryptography interest	18-20 minutes (decryption)

💡 Alternative: Let teams choose their difficulty for a "risk/reward" model (Hard puzzle worth 2-3 bonus points). This increases engagement but may lead to some teams overestimating their abilities.

Common Issues and Solutions

Problem	Solution
Team finishes extremely early (suspicious)	Spot-check their work. Ask them to explain their decryption method. May have copied or guessed.
Team can't find clue despite correct decryption	Verify decryption matches your answer key exactly. If yes, give area hint: "Check behind objects in the back corner."
Multiple teams stuck on same calculation error	Pause class, briefly review the concept (e.g., modulo operation) for everyone, then resume.
Team member not participating	Quietly assign them a specific task: "Can you calculate the ASCII values?" Individual grades may differ if severe.
Running out of time	Shorten presentation phase or allow teams to submit written reports instead. Extend next class if needed.
Clue card lost/stolen	Have backup cards ready. Quickly replace and don't penalize the team.
Calculator malfunctions or not available	Allow phone calculator use or provide online calculator access via computer.

Extension Activities (if time permits)

Cryptanalysis challenge: Give teams an encrypted message without a key and have them break it using frequency analysis
Create your own: Teams design a puzzle for another team to solve next class
Digital signature demo: Use actual Bitcoin block explorer to show real transaction signatures
Security debate: Discuss: "Is encryption more important for privacy or security?" (10 min)

Post-Activity Debrief (Next Class)

Return graded work and discuss:

Common mistakes: Review calculation errors (especially modulo operations)
Connection to course: "This signature verification is exactly how Bitcoin validates transactions"
Real-world scale: "You worked with small numbers. Real RSA uses 2048-bit keys!"
Security implications: Discuss what happens if private keys are compromised (connect to Mt. Gox hack, etc.)

Reusability Tips

Rotate puzzles: Create 2-3 versions of each difficulty level to prevent answer sharing between semesters
Change locations: Move clue hiding spots each time you run the activity
Laminate materials: Puzzle sheets and clue cards can be reused if laminated
Digital version: For online classes, use virtual escape room platforms or encrypted emails

Assessment Notes

Grading time estimate: 10-15 minutes per team (total ~60 minutes for a class of 20 students / 5 teams)

Focus grading on:

Verification calculations (most important for learning objectives)
Reflection quality (shows conceptual understanding)
Decryption methodology (even if answer wrong, was method sound?)

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