Affine Ciphers Spring 2014 - Fall 2020
A cipher with an encryption/decryption function of the form $$ f(c) = (sc + b) \bmod 26 $$ where $$\gcd(s, 26) = 1$$
is known as an Affine Cipher. The special case when $s = -1$ and $b = 25$ is known as the Atbash Cipher $$ a(c) = (25 - c) \bmod 26.$$
Instructions:
To encrypt or decrypt text
Enter the text in the first text field,
Select the scale factor and shift amount, and
Select whether or not the Atbash method is applied (first or last).
Click the Apply button.
Uppercase letters will be converted to lowercase letters. Any other characters including spaces and numbers will be left unchanged!
Enter the message below:
Select the Encryption/Decryption Parameters
Set the amount of scaling
s
, gcd(s, 26) = 1:
1
3
5
7
9
11
15
17
19
21
23
Enter the amount of shift
b
, -25 ≤
b
≤ 25:
Apply the Atbash Cypher?
No
First
Last
The results:
Prof. A. O. Hausknecht, Mathematics, UMass Dartmouth