If you have done some DevOps works before, you must be familiar with the tool
ssh-keygen. When a new key is generated, it will display a simple square ASCII art image called "random art image" (see following sample FYI). What's the purpose of it?
Generating public/private rsa key pair.
The key fingerprint is:
05:1e:1e:c1:ac:b9:d1:1c:6a:60:ce:0f:77:6c:78:47 you@i
The key's randomart image is:
+--[ RSA 2048]----+
| o=. |
| o o++E |
| + . Ooo. |
| + O B.. |
| = *S. |
| o |
| |
| |
| |
+-----------------+People usually memorize images and patterns faster and firmlier than plain texts. And it's also useless to memorize the entire string because the goal is validation rather than memorization (who will recite their private key?). Therefore, converting them to pattern assists people in validating keys faster becasue a subtle alteration will cause a totally different pattern. That's why random art images present.
This technique is from a paper titled Hash Visualization: a New Technique to improve Real-World Security published in 2000.