simple implementation of rsa

#include

int xcrypt(int v, int n, int e)
{
    int i, rc;
    for (rc = 1, i = 0; i < e; ++i)
    {
        rc *= v;
        rc %= n;
    }
    return rc % n;
}

int
main(void)
{
    int i, x, y;
    int p = 13, q = 29, e1 = 17, e2 = 257;
    int n = p * q;

    for (i = 0; i < n; ++i)
    {
        x = xcrypt(i, n, e2); // encrypt
        y = xcrypt(x, n, e1); // decrypt
        printf("%s: %d -> %d -> %d\n", y == i? "ok": "error", i, x, y);
    }

    return 0;
}