How are ciphers broken?

Question

How do ciphers and cryptic texts that aren’t digital get broken? Like the Zodiac killer’s for example

In: Other

Answer 1

If it’s a simple cipher then you can look for clues in letter patterns–for instance, in English the most commonly used letter is E, followed by T, A, O and N in that order, so you look for the most commonly-used symbols in the cipher and see if substituting them for those letters gives you anything readable. This obviously doesn’t work for more complex ciphers.