Mono-alphabetic and Playfair cipher

Question

Define:

a) Mono-alphabetic cipher

b) Playfair cipher

c) Transposition cipher

Answer 1

a) Mono-alphabetic cipher :

A mono-alphabetic cipher maps the plain alphabet to the cipher alphabet. In this, the single cipher alphabet is used per message.
 
b) Playfair cipher :

The best-known multiple-letter encryption cipher refers to the playfair, that treats the diagrams within the plain text as single units and transforms these units into the cipher text diagrams.

c) Transposition cipher :

Transposition cipher refers to a cipher that is achieved by carrying out some sort of the permutation over the plaintext letters.