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

int main (int argc, char *argv[])
{
    if (argc < 2 || strlen(argv[1]) < 10) {
        printf("./keygen 'yourname' (10 chars minimal)\n");
        return 1;
    }
    char *name = argv[1];

    int j = 0xc0;
    for (int i = 0; i < strlen(name); i++) {
        char c = name[i];
        c = c ^ j;
        c = c & 3;
        c = c << 1;

        switch(c) {
            case 0:
                // Do nothing
                break;
            case 2:
                name[i] = name[i] - c;
                break;
            case 4:
                name[i] = name[i] ^ c;
                break;
            case 6:
                name[i]= (c << 1) ^ name[i];
                break;
            default:
                printf("Unexpected value encountered");
                return 1;
        }
        j += 1;
        printf("%x", name[i]);
    }
    printf("\n");
}