Nov, 2018 : SHA1 vs SHA2 vs SHA256 – What’s the difference?

📅 November 12, 2018 - One of the most common topics that we field questions on is the Secure Hash Algorithm, sometimes known as SHA1, SHA2, SHA256. Obviously, the different numbers at the end mean something, but there are also misperceptions about what they’re used for, what hashing is and how it all plays into PKI and TLS.

Let’s start with some basic concepts about hashing and how it interacts with other functions of TLS.

What is a hashing algorithm?
Hashing is an algorithmic function that maps data of any size to a fixed length output. Sometimes people call this one-way encryption but that’s not completely accurate. When you hash something, it creates a hash value, which is the fixed length output we just mentioned. No two different pieces of data can ever produce the same hash value. In fact, even the tiniest tweak to a piece of data will result in different hash values.