Foreword I recently finished watching the TV series version of "The Three-Body Problem" directed by Yang, and I gained an astonishing new understanding of the impact of human actions on the world. Although it is a science fiction drama, its revelation of human nature is very profound. A long time ago, I came across a question and answer on Zhihu. The title was probably "If someone blows up all the storage servers of Alipay, will everyone lose all their money in Alipay?" ", I am ashamed to say that from that article, the author first fully understood "how to use various means to physically destroy service clusters", and then understood "how financial system designers carefully design a security system to protect data." And when I accidentally accessed root-servers while checking a piece of information, I thought of the problem in the title. With this question in mind, I decided to go back... 1. Understand DNS. Before answering this question, in the spirit of inquiring, we first need to understand the working principle of DNS and the management mechanism of the root domain name. 1.1 What is DNS? Well-known TCP/ IP protocol. The network layer defines IP (Internet Protocol) to transmit data from one device to another. Based on this idea, the concept of IP address was designed to number the device. For the IPv4 protocol, the IP address has a total of 32 bits and is divided into four segments (for example, 192.168.100.1), each segment is 8 bits. Details such as the classification of IP addresses and IP addressing will not be discussed in this article. IP is for computer equipment and is not easy for humans to recognize and remember. So humans invented the domain name (Domain…
Category: Networking
A Deep Dive into the ECDHE Algorithm
1. Basics of encryption and number theory
Before we formally talk about ECDHE, we need to talk about the RSA algorithm that is closely related to it. ECDHE was born on the premise of optimizing some features of RSA.
1.1 Asymmetric encryption
RSA algorithm is often used in asymmetric encryption. Asymmetric encryption generates a pair of keys. Common usage scenarios are:
- Public key encryption, private key decryption. This purpose is to Ensure data transmission security, because the content encrypted by the public key cannot be decrypted by others. Only the person holding the private key can decrypt the actual content;
- Private key encryption, public key decryption. This purpose is to Ensure data authenticity, because the private key cannot be leaked. If the public key can normally decrypt the content encrypted by the private key, it can be proved that the message was sent by the person holding the identity of the private key.
If you want to understand the RSA algorithm, you first need to start with several elementary number theory concepts.