OP here again, I finally got some time to implement some of the ideas discussed here. I'm very pleased to say that it all, finally, seems to work. And no errors or warnings.
Encryption:
# include <stdio.h>
# include <stdlib.h>
# include <unistd.h>
# include <string.h>
# include <math.h>
#define arrsize 1802
int main () fopen ("/home/USERNAME/keyfile.txt" , "r" );
char input[arrsize];
puts ("Enter your text as a single line, no paragraphs, max 1800 characters. Press Enter when finished." );
fgets (input, 1800 , stdin);
size_t k = strlen (input);
if (input[k - 1 ] == '\n' ){
input[k - 1 ] = '\0' ;
}
if (k > 1800 ){
puts ("Error, message was >1800 characters. Don't be a fag." );
return 1 ;
}
else {
printf ("\n\nVerifying your text input was length %lu and size %lu...\n" , strlen (input), sizeof for (int i=0 ; i<k; i++){
printf ("%c" , input[i]);
}
}
char key[k];
printf ("\n\nReading the key.\n" );
if (!Keyfile){
printf ("Error opening keyfile!" );
return 1 ;
}
else {[Expand Post] fgets (key, k, Keyfile);
}
printf ("Key array is of length %lu with size of %lu\n\n" , strlen (key), sizeof for (int i=0 ; i<k; i++){
printf ("%c " , key[i]);
}
char xor [k];
for (int i=0 ; i<k; i++){
xor [i] = (char ) (input[i] ^ key[i]);
}
printf ("\n\nExecuting XOR and storing in xor array of length %lu and size %lu\n\n" , strlen (xor ), sizeof xor ));
for (int i=0 ; i<k; i++){
printf ("%d " , xor [i]);
}
FILE *Cipher = fopen ("/home/USERNAME/ciphertext" , "wb" );
if (!Cipher){
printf ("Error writing to file!" );
return 1 ;
}
else {
printf ("\n\nWriting XOR array contents to binary file ciphertext" );
fwrite (xor , sizeof xor ), 1 , Cipher);
}
fclose (Keyfile);
fclose (Cipher);
printf ("\n\n" );
return 0 ;
}# include <stdio.h>
# include <stdlib.h>
# include <unistd.h>
# include <string.h>
# include <math.h>
#define size 1802
int main () fopen ("/home/USERNAME/keyfile.txt" , "r" );
FILE *Cipher = fopen ("/home/USERNAME/ciphertext" , "rb" );
FILE *Plain = fopen ("/home/USERNAME/plaintext.txt" , "w" );
char ciphertext[size];
if (!Keyfile){
printf ("Error opening keyfile" );
return 1 ;
}
else if (!Cipher){
printf ("Error opening ciphertext!" );
return 1 ;
}
else if (!Plain){
printf ("Error opening plaintext!" );
return 1 ;
}
else {
printf ("Reading ciphertext into array...\n\n" );
fread (ciphertext, 1800 , 1 , Cipher);
}
fseek (Cipher, 0L , SEEK_END);
size_t j = ftell (Cipher);
rewind (Cipher);
puts ("Printing contents of the ciphertext array to verify." );
for (int i=0 ; i<j; i++){
printf ("%d " , ciphertext[i]);
}
char key[j];
printf ("\n\nReading the key...\n\n" );
fgets (key, j, Keyfile);
printf ("Key array is of length %lu with size of %lu\n\n" , strlen (key), sizeof for (int i=0 ; i<j; i++){
printf ("%c " , key[i]);
}
char plain[j];
for (int i=0 ; i<j; i++){
plain[i] = (char ) (ciphertext[i] ^ key[i]);
}
printf ("\n\nExecuting XOR and storing in plaintext array of length %lu and size %lu\n\n" , strlen (plain), sizeof printf ("%s" , plain);
puts ("\n\nOutputting plaintext to plaintext.txt" );
fputs (plain, Plain);
printf ("\n\nAll done." );
fclose (Keyfile);
fclose (Cipher);
fclose (Plain);
return 0 ;
}