Principles of RSA algorithm

Symmetric encryption:

(1) Party A chooses a certain encryption rule to encrypt the information;

(2) Party B uses the same rule to decrypt the information.

This encryption mode has one of the biggest weaknesses: Party A must tell party b the encryption rules, otherwise it cannot be decrypted. Saving and passing a key is the most troubling question.

Asymmetric Encryption algorithm:

(1) Party B generates two keys (public and private). The public key is public and can be obtained by anyone, and the private key is confidential.

(2) Party A obtains the public key of party B, then uses it to encrypt the information.

(3) Party B obtains the encrypted information, decrypts with the private key.

This algorithm is very reliable, the longer the key, it is more difficult to crack. According to the already disclosed literature, the longest RSA key currently cracked is 768 bits. In other words, a key that is longer than 768 bits is not cracked (at least not publicly announced). Therefore, it can be considered that the 1024-bit RSA key is basically secure, and the 2048-bit key is extremely secure.

Principle:

Concept: coprime Relationship:

1. Any two prime numbers constitute a coprime relationship, such as 13 and 61.

2. One number is prime, the other is not a multiple of the former, and the two constitute coprime relationships, such as 3 and 10.

3. If the larger of the two numbers is a prime number, the two constitute coprime relationships, such as 97 and 57.

4.1 and any of the natural numbers are coprime relationships, such as 1 and 99.

5. P is an integer greater than 1, then p and p-1 constitute coprime relationships, such as 57 and 56.

6. P is an odd number greater than 1, then p and p-2 constitute coprime relationships, such as 17 and 15.

Euler functions

Principles of RSA algorithm