LETS TALK ABOUT SSH AND SSL/TLS

Hello everyone! I am Amila Munasinghe. I am studying at Department of Computing and Information Systems, Faculty of Applied Sciences, Sabaragamuwa University of Sri Lanka and this is my very first blog post. I hope to write a couple of articles about SSH, SSL protocols.

What is SSH?

Secure shell, or SSH for short, is a method of securely communicating with a remote computer. SSH is a command execution protocol that interacts with another system's operating shell to execute commands remotely. SSH was originally designed for UNIX-based computers, although it is now widely used on Windows.

You'll note that SSH uses TCP port 22 to communicate. Putty's other login methods, such as telnet and Rlogin, don't offer the same level of security as SSH. The SSH protocol was designed to replace insecure remote connection techniques. SSH is a cryptographic protocol that establishes a secure connection between two computers. The distant system shell is visible after the tunnel is formed, and shell commands can be securely relayed across the connection.

What is SSL/TLS?

We've combined these two methods into one because they're very similar. Both are still in use, although in network implementations, TLS is gradually replacing SSL. These are both cryptographic protocols, like SSH. The setup, however, is different. To ensure security and integrity to website transactions, an SSL/TLS connection makes use of the Public Key Infrastructure (PKI) and digital certificates.

Website security is provided via the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols. While SSL 2.0 and 3.0 are no longer supported by the IETF, they have been deprecated in favor of TLS (Some have suggested that TLS is an upgraded version of SSL 3.0). TLS, on the other hand, is more robust and secure in the face of new threats and weaknesses. When it comes to TLS versions, TLS 1.2 and 1.3 are the most recent versions that major browser authorities have adopted. TLS 1.2 enables advanced encryption such as ECC and AEAD cipher blocks, while TLS 1.3 enhances TLS 1.2's functionality while also preventing downgrade attacks.

SSL and TLS are handshake protocols. They're part of a server/client architecture, which involves sending and receiving requests and responses to establish a connection between two machines. An example of a TLS 1.3 handshake is shown below:

To enable a trust relationship between users and providers, SSL and TLS require digital signatures provided by Certificate Authorities. Once the link is established, sensitive data, such as that shared between a bank and its customers, can be safely transmitted. Port 443 is the standard TCP port for Hypertext Transfer Protocol over SSL/TLS (HTTPS).

Differences Between SSH and SSL/TLS Security Protocols

SSH and SSL/TLS are used for different things. Network administrators frequently utilize SSH for tasks that a typical internet user would never have to deal with. The normal internet user, on the other hand, uses SSL/TLS all of the time. When someone visits a website with a URL that begins with HTTPS, he is visiting a site that uses SSL/TLS.

SSH	SSL/TLS
Working based on network tunnels.	Working based on digital certificates.
A remote protocol	A security protocol
Runs on port 22	Runs on port 443
Data integrity is measured with algorithms like SHA, SHA-2, SHA-256	Data integrity is measured with the message digest and added to encrypted data before the data is sent.
It is used to reduce security threats for remote server login	It allows secure transition of data between a server and the browser thus, keeps information intact.
SSH uses a username/password authentication system to establish a secure connection.	SSL normally uses X.509 digital certificates for server and client authentication.
SSH is for securely executing commands on a server.	SSL is used for securely communicating personal information.
SSH follows authentication process by server’s verification done by client, session key generation, and client’s authentication	SSL follows authentication process by exchange of digital certificate

Similarities Between SSH and SSL/TLS

Because both SSH and SSL are three-digit abbreviations that begin with the same letter, it's acceptable if they're confused. However, there are some parallels. To begin, two (and all three) of these protocols are utilized in secure connections. Both employ encryption to keep data safe as it travels between network devices. The goal of both protocols is to establish a secure connection. Without these two methods, we would not be able to conduct business on the internet as securely as we do now.

Conclusion

While both protocols have various uses, the fundamental differences are evident. SSH is primarily a tool for technicians, whereas SSL/TLS provides a user-invisible security technique for websites. These two, of course, are not mutually exclusive. As part of its secure solution, SSH may use SSL/TLS. These adaptable protocols can be implemented in a number of different ways. With all of the internet hazards that we face these days, they are essential. It's again another warning that when using online tools, we must all be cautious and watchful.