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A fun, free platform for learning modern cryptography

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Learn By Doing

Learn about modern cryptography by solving a series of interactive puzzles and challenges. Get to know the ciphers and protocols that secure the digital world by breaking them.

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Level Up

Earn points by solving challenges. Finish categories to earn trophies and gain levels to track your progress. Can you reach the top of the scoreboard?

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Fresh Challenges

We are constantly creating new challenges to keep your crypto knowledge up to date. Expect exciting brainteasers and whole new categories as the site continues to grow.

New Challenges
Digestive Elliptic Curves 60
RSA vs RNG Misc 150
Decrypting TLS 1.3 Crypto on the Web 35
Decrypting TLS 1.2 Crypto on the Web 30
Authenticated Handshake Crypto on the Web 40
Weekly Top Users
#1 Nadja 2580
#2 Mago_Implacavel 1370
#3 Oberon 1320
#4 nami10 1290
#5 JetSam 1175
Recent Solves
Resisting Bruteforce VladikVT
Keyed Permutations VladikVT
Round Keys rasimhankunrava
Greatest Common Divisor anderwei
Size and Basis diffany
Recent Solutions
Diffie-Hellman Starter 2 HIGH0101 0
Extended GCD tom_baby 0
Greatest Common Divisor tom_baby 0
Noise Free epistemologist 0
You either know, XOR you don't tom_baby 0

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