main.c

3 Examples of basic Crytprography and BruteForce approcaces

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char * caesar(char key, char *text, int codingMode);

int main(){
 char key = 'X' , text[] = {"ABCDEFGH"} , *c;
 int codingMode = 0;

    printf("Eingabe: %s\n",text);

    c = caesar(key,text,0);
    printf("Codiert: %s\n",c);

    c = caesar(key,c,1);
    printf("Decodiert: %s\n",c);

    if(c != NULL)
    {
    free (c);
    c = NULL;
    }
    return 0;
}


char * caesar(char key, char *text, int codingMode){
    int sizeOfP = strlen(text), i = 0;
    char *c , k;

    k = key -'A';

    c = (char*) malloc(sizeof(char)*sizeOfP);
      if(c == NULL){
                printf("Zu wenig Speicherplatz!\n");
                return(1);
            }



    switch (codingMode) {

        case (0): {

                while( i < sizeOfP ){
                    c[i] = text[i]+k;

                    if (c[i] > 'Z')
                        c[i] -= 26;

                    i++;
                }

        break; // Ende Case 0 (Decode)
        }

        case (1) : {

                while( i < sizeOfP ){

                    c[i] = (text[i] - k) ;

                    if (c[i] < 'A')
                        c[i] += 26;

                    i++;
                }

            break; // Ende Case 1 (Encode)
        }

       // End Switch
    }

        c[i] = '\0';

    return c;
}