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Complete color edition
All student pages plus the instructor guide, with color cues for online viewing.
Download PDFFree classroom resource
BB84 Classroom Worksheet
A role-based activity that helps students see how basis choices, sifting, and eavesdropping fit together in quantum key distribution.
- 20–25 minutesplus discussion
- Small groupsAlice, Bob, and Eve
- Minimal prepworksheets and coins
What students do
Follow the protocol, then look for disturbance.
- 1Prepare and transmit
Alice records bits and bases; Eve and Bob make their own basis choices.
- 2Keep matching bases
The group marks each position KEEP or DROP, then compares the kept bits.
- 3Interpret the evidence
Students connect mismatches with the disturbance an eavesdropper can introduce.
Downloads
Choose the edition that fits your class.
The complete worksheet includes student role sheets and the instructor guide. Student-only files are ready to distribute directly.
Black & white
Complete print edition
Balanced, high-contrast pages designed for ordinary classroom printing.
Download PDFStudent handout
Student-only editions
Distribute the activity without the instructor notes.
Teaching support
Instructor guide
A compact reference for setup, pacing, debrief, and the real sampling method.
Download PDFTeaching note
The worksheet reveals every kept bit for clarity.
This classroom shortcut makes the first pass easy to follow. In an actual BB84 exchange, Alice and Bob publicly compare only a random sample of their sifted bits. The uncompared bits—not the revealed sample—can contribute to a secret key after further processing.
Reuse and attribution
Adapt it for your own classroom.
This resource is licensed under Creative Commons Attribution 4.0 International.
Suggested citation: Justice, Daniel. BB84 Classroom Worksheet. Version 1.0, 2026. Quantum Turtle. CC BY 4.0.