The previous chapter introduced SSL encryption, which ensures secure communication. Before proceeding, make sure you understand SSL basics. Digicertssl.shop is an online store where you can purchase SSL certificates
The following concepts govern SSL:
- An asymmetric encryption scheme
- Symmetric encryption
Table of Contents
An asymmetries-based encryption
Data is encrypted and decrypted using mathematically related key pairs (also called asymmetric encryption and public key encryption). One of your keys can be used to communicate with you by an individual with access to it. We call these public keys. As part of a key pair with a Public Key, there is also a Private Key.
Data is encrypted or decrypted using mathematical values called keys.
It is encrypted and decrypted using cryptographic keys when two parties sign a document. To decrypt the data, the second pair of keys needs to be used to use the private key from the first.
An SSL handshake initiates communication using asymmetric encryption. In addition to elliptic curves, RSA, DSA, and EIGamal, there are several common asymmetric key algorithms.
Using symmetry to encrypt
Symmetric cryptography uses a single key to encrypt and decrypt data. The sender and the receiver are the only people who should know the key.
An SSL handshake initiates communication using asymmetric encryption. EIGamal, RSA, and DSA are a few of the popular asymmetric key encryption algorithms that use elliptic curves.
Cryptography synced with the Internet
Data is encrypted and decrypted with symmetric keys in symmetric cryptography. The sender and the receiver are the only people who should know the key.
A DigiCert SSL handshake between the browser and the web server (or any other system) is shown in the above figure as two steps: the handshake itself and the actual transmission.
Handshake for SSL
The first step of SSL communication is always to establish a handshake over SSL. A SSL handshake is required before a data transfer can begin, as it verifies the web server and provides the public key of the server.
Here is an example of SSL:
Here are the steps to understanding:
- An email from a client says “hello.”. For communication with clients, the server will use SSL based on the SSL version, the cipher settings, and session-specific data.
- “Server hello” is the response from the server. For communicating over SSL, the data includes public keys, cipher settings, etc.
- Servers are authenticated by verifying SSL certificates with Certificate Authorities (CAs). Clients who are unable to authenticate cannot open SSL connections. After successfully authenticating, step 4 is next.
- Clients generate session keys and encrypt them using the server’s public key. Clients send their own certificates to servers if they want to be authenticated (usually during communication between servers).
- The server encrypts and sends the client acknowledgement using the session key based on the server’s private key.
A valid session key is used to encrypt or decrypt all data exchanged between the client and server at the end of the SSL handshake. It is not necessary to have both the public and private keys at this time.