Difference Between SSL, TLS and SSH

Tuesday, 30 November 2010

There are three major types of security that are used on modern day web pages.  They are SSL, TLS and SSH.  SSL or Secure Sockets Layer is a public key that is used to allow internet services to be used once the key has been accepted.  The key is usually in the form of a certificate which proves that the website is authentic.  The next one is TLS or Transport Layer Security and is used on nearly the same level as SSL.  The final one is SSH, also known as Secure Shell and is used for security on Linux based systems.  They are all different but offer security in one way or another which can help prevent traveling on websites that are pretending to be authentic.

What is SSL?

SSL is designed to allow an accessing device or application to connect through ports associated with SSL for verification.  Logging into the destination is handled then routed for verification then allowed in based on whether or not the key is the same for the request.  Not all web browsers will alert users of changes in security measures such as those.

What is TLS?

TLS works in a similar fashion but helps to prevent eavesdropping and tampering with information that is sent between the two locations.  The server does a large amount of encrypting of data being transferred and pulls information for the digital certificate.  If the information is correct the TLS will continue until the connection is completed.

What is SSH?

SSH has an added feature in it that makes it much different than SSL and TLS.  There is a username and password that is used for authentication.  The process will request the username and password and send the request to the server.  The server uses the password and username information to encrypt the connection and asks the server to allow entry into the page when the password and username are correct.

Although these three security options are great, they all have major flaws in them.  For one thing, browsers can disable or ignore them (SSL and TLS) when specific settings are in place.  This means that even if the information was returned as a non-matching certificate, then the website is being visited without a complete trust from the browser.  SSH will simply not work and access will be denied if disabled somehow.  The use of these specific options make the browsing experience more secure but they only add a trivial amount of security to most people's perception of what they are intended for.

The use of these tunneling security options can be used in some interesting ways such as running applications when a connection is made or even being used to send file transfers through specific ports. Of course having them able to perform such feats requires extensive knowledge of how they work, being able to intercept them, decrypt, insert instructions, re-crypt and pass off as the original handshake message to perform the wanted action.  This is not an easy feat for most computer users to accomplish.