Fall 2010/Lecture 318 RSA Description (cont.) Encryption Given a message M, 0 < M < nM  Z n  {0} use public key (e, n) compute C = M e mod n C  Z n  {0} Decryption Given a ciphertext C, use private key (d) Compute C d mod n = (M e mod n) d mod n = M ed mod n = M