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COURSE: Data & Network Security MARKS:

/10

TOPIC: Cryptographic CODE: BCN2023

ASSESSMENT: Lab

Shee3NO: 3

DURATION: 2

hours

#include ;

#include ;

main()

{

char input[80]; // Message to be encrypted

// variable used

int key =0;

int i;int x;

int j;

char d;

printf("************************************************************");

printf("\n\t\t\t1.Encryption.");

1

1. What you should do :

Problem :

Using Previous Code from Labsheet 2 implement Decryption and Triple DES

Substitution

Cipher algorithm in C programming.

Description :

i. Add decryption function in your code

ii. Add encryption function as triple DES

iii. Use Switch & Case statements as your menu selection in your code

iv. Eg. Case 1 for Encryption, Case 2 for Decryption and Case 3 for Triple DES

Triple DES algorithm:

If,C = CICSO, and p = 3 then

E1= FLFVR

E2= IOIYU

E3= LRLBX

INSTRUCTION:

CODING:

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printf("\n\t\t\t2.Decryption.");

printf("\n\t\t\t3.Encyption Triple DES.");

printf("\n\t\t\t4.Exit");

printf("\n************************************************************");

printf("\n\n\t\tEnter Your Choice: ");

scanf("%d",&d);

printf("\n************************************************************");

switch(d)

{ case 1:

// Enter shift amount

printf("\n\n\nEnter shift amount (1-25) : ");

scanf("%d", &key);

// enter message

printf("Enter message to be encrypted: ");

scanf("%s", &input);

for(x=0; input[x] != '\0';x++)

{

// check if letter is captial or lower case

if (input[x]>='A' && input[x]='a' && input[x]

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{

if(input[i] >= 'A' && input[i]

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default:printf("\n\t\tWrong choice. Run the program again.");

break;

}

}

No Type of algorithm Output

1 Encryption (Caesar Cipher)

2 Decryption (Caesar Cipher)

3 Triple DES

4

OUTPUT: