(out *Nat) Exp(x *Nat, e []byte, m *Modulus) *Nat { if !m.odd { panic("bigmod: modulus for Exp must be odd") } // We use a 4 bit window. For our RSA workload, 4 bit windows are faster // than 2 bit windows, but use an extra 12 nats worth of scratch space. // Using bit sizes that don't divide 8 are more complex to implement, but // are likely to be more efficient if necessary. table := [(1 << 4) - 1]*Nat{ // table[i] = x ^ (i+1) // newNat calls are unrolled so they are allocated on the stack. NewNat(),...