Cryptography Tutorial | Part 2

Hey guys the last tutorial we talk about the Ceaser Cipher Algorithm in this tutorial we will talk about Polyalphabetic Cipher we will talk about the Encryption & Decryption process like part one.

Encryption:

now let's imagen that we want to encrypt this word security we will use the same sequence

0 1  2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

now we will split security word to groups three letters in the group to be like that sec uri ty there is two letters we will skip it and continue, the encryption way it's

1. the first letter will be moved 3 letters to the right

2. the second letter will be moved 5 letters to the right

3. the third letter will be moved 7 letters to the right (if the numbers is finished we will start from the first from zero)

so the encryption to this letters sec is:

S => V

E => J

C => J

the same with this URI:

U => X
R => W
I => P

with the last letters, we will do the same thing but without the last step because the length of the letter equals 2 we just will do the first  & second steps this letters TY will be like that:

T => W

Y => D

now the encryption of Security word is VJJXWPWD now we encrypt the word so now let's decrypt it.

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Decryption:

the first thing we will do with the encrypted word just split it to three letters to be like this VJJ XWP WD the decryption way:

1. first letter will be moved 3 letters to the left

2. second letter will be moved 5 letters to the left

3. third letter will be moved 7 letters to the left

so the decryption to this VJJ is:

V => S

J => E

J => C

and the same with XWP:

X => U

W => R

P => I

and same with this two letters WD:

W => T

D => Y

the decryption of this VJJXWPWD is SECURITY so this how to encrypt & decrypt with Polyalphabetic Cipher, I hope this topic is helpful to anyone, thanks for reading.