Thu 22 Oct 2020

A Visual Guide to Regular Expression

It’s a common task in NLP to either check a text against a pattern or extract parts from the text that matches a certain pattern. A regular expression or “regex” is a powerful tool to achieve this.

While powerful, regex can feel daunting as it comes with a lot of features and sub-parts that you need to remember.

In this post, I will illustrate the various concepts underlying regex. The goal is to help you build a good mental model of how a regex pattern works.

Source: A Visual Guide to Regular Expression, an article by Amit Chaudhary.

SSH & SSL — Step-siblings or Rivals?

People often wonder whether SSH uses SSL/TLS for traffic encryption. The short answer is NO, even though both protocols have much in common, under the hood SSH has its own transport protocol, independent from SSL.

  • Both of them were created to secure and encrypt traffic between clients and servers (SSL for website traffic, SSH for remote control over host)
  • They both start with asymmetric encryption in order to negotiate static key for the rest of the session using symmetric encryption (SSH uses proprietary key exchange protocol, SSL/TLS uses PKI infrastructure)

Also keep in mind that both were developed almost in parallel somewhere in 1995 (SSL1.0 was first though) so they couldn’t actually use each other’s implementation at the time.

However, instead of comparing both protocols, I would like to dedicate most of this post to the attempt to combine both protocols in order to achieve the most secure, scalable and easy-to-use mass scale SSH control over multiple Linux servers.

Source: SSH & SSL — Step-siblings or Rivals?, an article by Artiom Levinton.