Algorithm

1. Construction Phase:
   1. Select two random large primes p, and q.
   2. Calculate N = pq and ϕ(N) = (p−1)(q−1).
   3. Pick an encryption key e that is coprime with ϕ(N).
   4. Calculate the decryption key d such that de ≡ 1 (mod  ϕ(N)).
2. Operation Phase:
   1. Make the public key (N,e) public, and keep p, q and d as secrets.
   2. Sender encrypts its message M as E(M) = M^e (mod  N).
   3. Receiver decrypts it by calculating E(M)^d = M^ed ≡ M (mod  N).