Jason Parms

SSH and SSL/TLS are employing Asymmetric cryptography. These security protocols are intended to keep your personal information private during data transmission and secure communication over the Internet and public networks.

SSH (Secure Shell) and SSL/TLS (Secure Sockets Layer/ Transport Layer Security) are very similar as compare of security aspects – encryption, authentication and integrity processes. But when you are hunting for SSH vs SSL/TLS, here we are exploring similarities and differences between SSH vs SSL/TLS protocols.

What is SSH?

Secure shell, more commonly known as SSH, is a way to securely communicate with a remote computer. SSH is used for executing commands remotely by interacting with another system’s operating shell. Originally created for UNIX-based computers, SSH is now easily available on Windows.

You will notice that SSH runs on TCP port 22. Other login methods in Putty — telnet and Rlogin, for instance — don’t have the security that SSH does. The SSH protocol was created to replace insecure protocols for remote connections. SSH is a cryptographic protocol that creates a tunnel between two remote computers. Once the tunnel is established, the remote system shell is visible, and shell commands can be securely transmitted across the connection. Here is an illustration of an SSH handshake:

SSH Handshake

What is SSL/TLS?

We combine these two protocols as one because they do much the same thing. Both are still used, but TLS is gradually replacing SSL in network implementations. Like SSH, these are both cryptographic protocols. But the setup is different. An SSL/TLS connection uses the Public Key Infrastructure (PKI) and digital certificates to provide security and integrity to website transactions.

Secure Sockets Layer (SSL) and Transport Layer Security (TLS) are mechanisms for securing websites. While SSL 2.0 and 3.0 are obsolete version, they have been deprecated by IETF in favor of TLS (Some have suggested that TLS is an upgraded version of SSL 3.0). The difference is that TLS is more robust and secure against modern threats and vulnerabilities. If we look at TLS versions, then TLS 1.2 and 1.3 are recent versions that are adopted by major browser authorities. TLS 1.2 supports advanced encryption like ECC and AEAD cipher blocks while TLS 1.3 adds features of TLS 1.2 as well provides downgrade attack prevention.

SSL and TLS are handshake protocols. They are part of a server/client architecture that involves requests and responses to negotiate a connection between two computers. Here is an illustration of a TLS 1.3 handshake:

ssl2buy-tls12-13

SSL and TLS use digital signatures generated by Certificate Authorities to enable a trust relationship between users and providers. Once the connection is established, it becomes possible to securely transmit sensitive information, such as might be passed between a bank and its customers. The standard TCP port used for Hypertext Transfer Protocol over SSL/TLS (HTTPS) is port 443.

SSH vs SSL/TLS – Differences Between both Security Protocols

SSH and SSL/TLS generally have different purposes. SSH is often used by network administrators for tasks that a normal internet user would never have to deal with. SSL/TLS, on the other hand, is used by the average internet user all the time. Any time someone uses a website with a URL that starts with HTTPS, he is on a site with SSL/TLS.

SSH
(Secure Shell)
SSL/TLS
(Secure Socket Layer/Transport Socket Layer)
SSH runs on port 22 SSL runs on port 443
SSH is for securely executing commands on a server. SSL is used for securely communicating personal information.
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 working based on network tunnels. SSL is working based on digital certificates.
SSH is a remote protocol SSL is a security protocol
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 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
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.

Similarities Between SSH and SSL/TLS

It’s understandable that someone might get SSH and SSL confused, since both are three-digit abbreviations that start with the same letter. But there are other similarities. First, these are both (and all three) protocols that are used in secure connections. Both use encryption to protect data that passes between two network devices.

The purpose of both types of protocols is to create a reliable connection. Without these two mechanisms, we would not have the security necessary to conduct business on the internet that we have today.

Conclusion

While there are other applications for these protocols, the basic differences are clear. SSH is generally a tool for technicians, and SSL/TLS is a mechanism for securing websites that is transparent to the user. Of course, these two are not mutually exclusive. SSH may use SSL/TLS as part of its secure solution. There are a variety of possible implementations for these versatile protocols. They are necessary these days with all the online threats that we face. It’s another reminder that we all need to be careful and vigilant when using online resources.