AlphaCoderAlphaCoder

Spy Party Secret Code Mission

Agent briefings to decode with three secret codes

Turn any get-together into a spy mission. New agents work through a stack of coded briefings — some in the A1Z26 number code, some in a Caesar shift-3 cipher, some in the Atbash mirror alphabet — decoding words like SECRET, AGENT and MISSION on their way to the final meeting password (MIDNIGHT). The host answer key lists every solution so you can run it with zero prep. Print the mission and answer key below, or read the briefings on this page.

Printable PDF — free to download & print

Download Student PDFAnswer Key (PDF)

How to use this worksheet

A printable spy-party mission. Every briefing is written in code — A1Z26 (A=1), a Caesar cipher shifted by 3, or the Atbash mirror alphabet. New agents decode each briefing to complete the mission and learn the meeting password. The host answer key has every solution.

Exercises

  1. 1. Briefing 1 — Decode your clearance (A=1): 19 5 3 18 5 20
  2. 2. Briefing 2 — Decode your role (Caesar shift 3): DJHQW
  3. 3. Briefing 3 — Decode the assignment (A=1): 13 9 19 19 9 15 14
  4. 4. Briefing 4 — Decode the order (Atbash): WVXLWV
  5. 5. Briefing 5 — Decode the exit plan (Caesar shift 3): HVFDSH
  6. 6. Briefing 6 — Decode the clearance level (Atbash): GLK HVXIVG
  7. 7. Briefing 7 — Decode the item to recover (A=1): 6 9 12 5
  8. 8. Briefing 8 — Encode your code name (A=1): SPY
  9. 9. Final — Decode the meeting password (Caesar shift 3): PLGQLJKW

Full solutions are on the downloadable answer key (PDF).

Related worksheets & tools