Some ciphers have simple keys, others, complex ones. The key for a cipher used by Augustus Caesar, some 2,000 years ago, was simple enough: The receiver just had to shift the alphabet one position.

Hint #2 for Playfair Cipher Back to Hint #1 Using the same methods for trying to locate the crib RED PENGUIN FRENZY, we note that it can be segmented either as RE DP EN GU IN FR EN ZY or -R ED PE ...

The banner included the keyword “foresight,” which allowed the curious to use the Vigenère cipher method to decode a message hidden in the chart’s letters: “You may have vision but ours ...

Shakespeare noted that uneducated folks “know not how/ To cipher what is writ in learned books,” but these learned books are a cipher to everybody.

This brief message, which former NASA administrator George Low named ‘The Martian Cipher’, was intercepted in 1969. It took the space agency almost 50 years to decode it. This deciphering is ...

How to Cipher Like a Soviet See if you can figure out how the American code-breakers unraveled the complexities of the Russian codebook ...