复旦大学：《密码学基础》课程教学资源（课件讲稿）02 Introduction to Cryptography -Classical Encryption Techniques（cont.）

復大辱软件学院 LiST

LiJT 16

Playfair Key Matrix a 5X5 matrix of letters based on a keyword fill in letters of keyword(sans duplicates fill rest of matrix with other letters eg. using the keyword MONARCHY MONAR CHYBD EFG工K 工PQs宜 UVVWXZ 復大辱软件学院 LiST

LiJT 17 Playfair Key Matrix • a 5X5 matrix of letters based on a keyword • fill in letters of keyword (sans duplicates) • fill rest of matrix with other letters • eg. using the keyword MONARCHY MONAR CHYBD EFGIK LPQST UVWXZ