Brief description of RSA algorithm

The RSA algorithm is currently the most widely studied asymmetric encryption algorithm. The security of this algorithm is based on the large number decomposition problem. It has resisted a large number of attacks in the past. The specific description of the algorithm for RSA key generation and encryption and decryption as follows:

(1) Select two large prime numbers p and q;
(2) Calculate n=p q, z=(p-1) (q-1); here, the length of n converted into binary is the key length, typical value It is 1024 bits;
(3) Choose a number that is relatively prime to z, and record it as d;
(4) Find e that satisfies e*d=1modz;
(5) That is, the public key is (e, n), and the private key is (d , n);
(6) Divide the plaintext to be encrypted into blocks, so that the plaintext message P of each block falls in the interval 0<=P<n. Ciphertext C=P^e(mod n);
(7) Plaintext P=C^d(mod n).