Math Applied math Explore the greatest problems we have faced from prehistoric through modern times. Community Questions 31 10 17 20 Journey into cryptography How have humans protected their secret messages through history? What has changed today? 17 6 Journey into information theory We've always been communicating.... as we moved from signal fires, to alphabets & electricity the problems remained the same. 3 8 Challenges Solve problems using Mathematics, Computer Science and more! Applied math Community Questions Topics Journey into cryptography Journey into information theory Challenges Challenges Solve problems using Mathematics, Computer Science and more! Subscribed Subscribe Cryptography challenge 101 The first challenge in the Cryptography series Introduction The discovery Clue #1 Clue #2 Clue #3 Crypto checkpoint 1 Clue #4 Checkpoint Crypto checkpoint 2 Crypto checkpoint 3 What's next?