What makes up SSL

SSL is a combination of components working together in a specified order to create an encrypted connection. When you look at Cryptography, a single component such as AES just provides the encryption. If we didnt have Diffie Helman to provide a secure key setup, then at the start of the connection we would need to provide the key in clear text so that the client could decrypt the AES data.

The following table is an example of how we interpret a SSL cipher such as those found here at openssl ciphers website. In this example we will look at TLS_DHE_RSA_WITH_AES_128_CBC_SHA256. Further below we go into details to understand each component and provide further options

Protocol

A Protocol (eg SSLv3, TLSv1.2) is what defines how an SSL connection is constructed. Within each protocol is a set of minimum and maximum components which can be used (see protocol features matrix below). Each protocol represents the understanding of the day, so each new protocol is more secure than the last based on everything we know about breaking cryptography or fixing faulty components. The protocol also defines the order of events that must be completed before transmiting encrypted data eg the key exchange.

Key Exchange

Keys exchange is the setup of the master secret which creates the key for encrypting and decrypting the data.

Procedure: In TLS1 with a clean RSA key, the actual RSA key is used for encrypting connections.

Perfect Forward Secrecy (PFS)

PFS effectivly changes the master key several times during a session or over a given period of time. The key that generated the public certificate

Cipher

HMAC

PKI Theory

Certificate Authority

Certificates