[Java] Vigenère Cipher (ASCII)

          Hello, Reader ^^! Back again with source code ^^! This time the source code is Vigenère Cipher for ASCII. The source code written in Java, translated from C++ version. It is a bit different than the Alphabet version. This time the non-alphabet are also encrypted (for the alphabet version, non-alphabets are ignored). Okay, let me explain abit again but with ASCII version.

Just say I have plaintext "Hello World!". I want to encrypt it using key "KEY". If encrypt it using Vigenère Cipher, here will be happens:

Plaintext

H

E

L

L

O

W

O

R

L

D

!

Ciphertext

K

E

Y

K

E

Y

K

E

Y

K

E

Y

The key becomes "KEYKEYKEYKEY". Yup, it is repeated based on the length of the plaintext.


Using the C_i = (P_i + K_i ) mod 256 (C is Ciphertext, P is Plaintext, K is Key, i is Index), it will give result :
"³Êå×Ô™ÂÔë×Éš".


For the Auto-Key, it also uses ASCII range. Okay, that's all I can say. Thank you for reading ^^!

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