void encrypt()
{
printf("\nEnter filename of file to be encrypted: ");
scanf("%s",&source_filename);
source = fopen(source_filename, "r");
printf("Enter filename of file to store the encrypted data: ");
scanf("%s",&destination_filename);
destination = fopen(destination_filename, "w");
printf("Enter the keyword: ");
scanf("%s",&keyword);
n = strlen(keyword);
while((data.character = fgetc(source)) != EOF)
{
key.character = keyword[i%n];
data.decimal = (int)data.character;
key.decimal = (int)key.character;
decimal_to_binary();
half_binary_to_decimal(0,4,8);
decimal_to_hexadecimal();
half_binary_to_decimal(4,8,8);
decimal_to_hexadecimal();
i++;
}
printf("Data was encrypted successfully...");
fclose(source);
fclose(destination);
}
///////////////////////Converts binary to hexadecimal
char binary_to_hexadecimal(char *string){
int i,j,value=0,sum=0; //binary to decimal
for(i=3,j=0;i>=0 && j<4;i--,j++)
{value=(string[i]-48)*power(2,j);
//printf("value is =>%d\n",value);
sum=sum+value;
}
return decimal_to_hexadecimal(sum); //decimal to hexadecimal
}
