1. Transposition Ciphers
Reference
Matt Bishop, Computer Security, Addison Wesley, 2003.

2. Transposition Ciphers (p.2)
A transposition cipher rearranges the plaintext to form the ciphertext.
There is no substitution of characters.
The key of the transposition cipher is a permutation function.

3. Transposition Ciphers (p.3)
A simple example is the “rail fence” cipher.
Let M be a sequence such as “HELLO, WORLD”.
Ignore spaces and punctuation, and rewrite the string into two rows:
HLOOL
ELWRD
The ciphertext C becomes “HLOOLELWRD”