inv_mcol
#define inv_rnd(y,x,k,c) (s(y,c) = inv_mcol((k)[c] ^ no_table(x,t_use(i,box),inv_var,rf1,c)))
#define ff(x) inv_mcol(x)
cx->ks[i] = inv_mcol(cx->ks[i]);
cx->ks[i] = inv_mcol(cx->ks[i]);
cx->ks[i] = inv_mcol(cx->ks[i]);