This project is designed for encrypting and decrypting the text using Java Programming Language.
This project is designed for encrypting and decrypting the text using Java Programming Language.
The Caesar Cipher is the simplest and oldest encryption technique. It is a method in which each letter in the plaintext is replaced by a letter with some fixed number of positions down the alphabet. For this reason, the shift cipher technique is called the Caesar cipher. The Caesar cipher is a kind of replacement (substitution) cipher, where all letter of plain text is replaced by another letter. It works with alphabets only.
PlainText means readable text. For eg: Hello everyone.
CipherText means text that has been encrypted and therefore unreadable. For eg: $%UFU%F^R
Formulas
1.)For Encryption : E(x) = ( pt + n ) mod 26
2.)For Decryption : D(x) = ( ct - n ) mod 26
where
pt denotes plaintext.
ct denotes ciphertext.
n denotes the key value.
E and D denote Encryption and Decryption.
In the above, if the result is not in the range 0 - 25 i.e. if pt+n and ct-n are not in the range 0 - 25 then we have to add or subtract 26.
For example: If D is -3 then add -3 with 26 and 23 as the answer.
Key-Value Table
For Example: Use the Caesar cipher to encrypt and decrypt the message "CODERSPACKET," and the key value of this message is 3.
Encryption
PlainText Encryption Formula: (x + n) mod 26 CipherText
C(02) (02 + 3) mod 26 05->F
O(14) (14 + 3) mod 26 17->R
D(03) (03 + 3) mod 26 06->G
E(04) (04 + 3) mod 26 07->H
R(17) (17 + 3) mod 26 20->U
S(18) (18 + 3) mod 26 21->V
P(15) (15 + 3) mod 26 18->S
A(00) (00 + 3) mod 26 03->D
C(02) (02 + 3) mod 26 05->F
K(10) (10 + 3) mod 26 13->N
E(04) (04 + 3) mod 26 07->H
T(19) (19 + 3) mod 26 22->W
So,The encrypted message is "FRGHUVSDFNHW"
Decryption
PlainText Encryption Formula: (x + n) mod 26 CipherText
F(05) (05 - 3) mod 26 02->C
R(17) (17 - 3) mod 26 14->O
G(06) (06 - 3) mod 26 03->D
H(07) (07 - 3) mod 26 04->E
U(20) (20 - 3) mod 26 17->R
V(21) (21 + 3) mod 26 18->S
S(18) (18 - 3) mod 26 15->P
D(03) (03 - 3) mod 26 00->A
F(05) (05 - 3) mod 26 02->C
N(13) (13 - 3) mod 26 10->K
H(07) (07 - 3) mod 26 04->E
W(22) (22 - 3) mod 26 19->T
So,The decrypted message is "CODERSPACKET"
ALL POSSIBLE OUTPUTS
Submitted by Shiddhant Gupta (Shiddhant123)
Download packets of source code on Coders Packet
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