A brief introcution to SSL.

SSL/TLS

Key word : Encription,SSl,TSL,TLS certificate,HTTPS,keys, How to install a certificate on a website

A little history

  • Netscape originally invented SSL in the mid-90s
  • Google began marking unencrypted sites Not Secure

Problem

When sending a message between two parties you have two problems that you need to address

  1. How do you know that no one has read the message
  2. HOw do you know that no one has changed the message

Answer

  1. Encrypt it. This makes the message unreadable
  2. Sign it. This allows the recipient to be confident that it was you who send the message, without modified.

Both of these processes require the use of keys.

Encription

The internet is designed to transfer free infomation on its born.HTTP transfer with plain text without encription

  • Symmetric encription(Two-way encription ):The (private) key is used to encrypt and decrypt.
  • Key exchange is important problem
  • Asymmetric encription: public-private key pair. Public key is used to encription and private key is used to decription.

Keys

These keys are simply numbers (128 bit being common) that are then combined with the message using a particular method, commonly known as an algorithm- e.g. RSA, to either encrypt or sign the message.

SSL certificates

How do you know that a particualr key belongs to a person/entity?

SSL certificate serve as a ID card/passport in everyday life, which established a link between a photo and a person, and that link is verified by a trusted authority(passport office)

A digital certificate(such as SSL certificate) provides a link between a public key and an entity that has been verified(signed) by a trusted third party(A certificate authority)

A digital certificate provides a convenient way of distributing trusted publick encryption keys.

Exchanging keys-Public Key Infrastrtucture

  • SSL Secure Sockets Layer, the original encryption protocol used with HTTPS
  • TLS Transport Layer security, the more recent encryption protocol has replaced SSL in response to known vulnerabilities in SSLv3.
  • HTPS security version of HTTP
  • PKI entire trust model that facilitates public key encryption

SSL/TSL hand shake

TLS1.2 handshake tls1.2 handle shake

TLS1.3 handshake tls1.3 handle shake

Reference

  1. TLS 101
  2. SSL and SSL Certificates Explained For Beginners
  3. How to fix the SSL/TLS Handshake Failed error