errors.New("crypto/rsa: invalid prime") } if pN.Mul(qN, N).IsZero() != 1 { return errors.New("crypto/rsa: p * q != n") } // Check that de ≡ 1 mod p-1, and de ≡ 1 mod q-1. // // This implies that e is coprime to each p-1 as e has a multiplicative // inverse. Therefore e is coprime to lcm(p-1,q-1) = λ(N). // It also implies that a^de ≡ a mod p as a^(p-1) ≡ 1 mod p. Thus a^de ≡ a // mod n for all a coprime to n, as required. // // This checks dP, dQ, and e. We don't check d because it is not actually //...