Other polyalphabetic Substitutions

Question 1

Homophonic Substitution

Answer 1

Homophonic substitution was one of the earlier attempts to make substitution ciphers more robust by masking the letter frequencies. Plain text letters map to more than one cipher text symbol

Question 2

Null Ciphers

Answer 2

Essentially the message is hidden in unrelated text. Example:

Message:”some morning we having m8”

Numbers: 20, 5, 7, 10 (prearrenaged)

Secret Message: “Launch the Missles”

Question 3

Book Ciphers

Answer 3

The simplest implementation is to send coordinates for words. So, for example, 3, 3, 10 means to go to page 3, line 3, and the 10th word. In this way, you can specify words with coordinates and write out entire sentences.

Question 4

Rail Fence Ciphers

Answer 4

The rail fence cipher may be the most widely known transposition cipher. You take the message you want to encrypt and alter each letter on a different row. So “Attackatdawn” is written as A t c a d w t a k t a n

Question 5

The Enigma Machine

Answer 5

Invented in WWII it was an electronic based cipher system.