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### Course: Computer science theory > Unit 2

Lesson 3: Cryptography challenge 101# Introduction

## HOW TO PLAY

This challenge is for

**all ages**, it doesn't assume you have any specialized knowledge.It builds off the ideas presented in the Ancient Cryptography tutorial

All other information you need can be found within Khan Academy.

Through this challenge there will be exercises to assess whether you broke the

**encryptions.**## Q&A RULES

Please

**do not**post__successful decryptions__in the Q&A (this is classified information!)Please

**do**post ideas/hints to help your fellow users (especially if you solved it)## Want to join the conversation?

- How many people have completed the entire challenge?(16 votes)
- This whole article was kind of confusing.(9 votes)
- how do you play?(4 votes)
- This is not really a game, it's a challenge on cryptography. You need to decipher clues 1, 2, 3, and 4 and the discovery to find the answers to crypto checkpoints one, two, and three.(8 votes)

- This is probably the most underrated content on Khan Academy... I completed it a couple years ago. It's challenging, but really fun! It's extremely satisfying if you're someone who likes to solve puzzles!(6 votes)
- Yeah, that is great but you should put your tips and thanks messages in the tips and thanks section.(2 votes)

- can I use Cryptography in coding programs like c++ or python?(3 votes)
- The question is poorly worded. Yes, you can create encryption methods using many programming languages where c++ and python are included.(1 vote)

- ok anything else we should know?(2 votes)
- What is the status on a new cryptography challenge?(1 vote)
- um... where's the crypto challenge, exactly?(1 vote)
- If you continue on there is the crypto challenge in this activity.(1 vote)

- how do you do the phi method(1 vote)
- from what I understand the phi method is where you take any number an calculate the number of prime numbers leading up to it

if the number is already a prime then simply subtract one :)(1 vote)

- Where can I get more in deep with this

And have some practice problem(1 vote)