This sequence is infinite, but you may recognize it after just 13 numbers. What is the 14th number? Please type in the numeric expression of the number.

In this challenge you shall break the Caesar encryption in its original form.

This sequence is infinite, the first 9 numbers are given. What are the 10th and 11th number?

The Caesar encryption, a very simple example of a monoalphabetic substitution.

The Beaver Code is a transposition cipher. Apart from the solution of this challenge, can you find a formula for any given ciphertext length, which generates the permutation needed to decrypt the ciphertext?

This number sequence is cyclic. Can you find out the fifth and sixth number?

After the Order of the Templar has become very powerful, enviers try to crush it. The knights receive an encrypted letter but the key does not arrive. Does this letter contain the warning that would have saved the knights from being arrested?