Encryption is divided into two methods: symmetric encryption and asymmetric encryption.
In symmetric encryption algorithms, the same key is used for encryption and decryption. That is, the same key is used for encryption and decryption. Therefore, if the symmetric encryption algorithm wants to ensure security, the key must be kept secret. It can only be known to those who use it and cannot be made public.
In an asymmetric encryption algorithm, the key used for encryption and the key used for decryption are different. One is used as a public public key, and the other is used as a private key that no one can give. Information encrypted by the public key can only be decrypted by the private key. Information encrypted by the private key can only be decrypted by the public key.
Because symmetric encryption algorithms are much more efficient and perform better than asymmetric encryption algorithms, symmetric encryption is often used in interactive scenarios.
What's in the certificate? Of course, there should be a public key, which is the most important; and the owner of the certificate, just like your name and ID number on the household registration book, indicating that the household registration book belongs to you; there is also the issuing agency and certificate of the certificate The validity period is a bit like which district public security bureau is the agency on the ID card and how many years it is valid for.
The public key and private key are mainly used to transmit the secret key of symmetric encryption, and the real communication of large amounts of data between the two parties is carried out through symmetric encryption. This is the general idea of the HTTPS protocol.
This article is a study note for Day 15 in September. The content comes from Geek Time's "Internet Protocol". This course is recommended.