randomart.py

A script to present BLAKE2b hashes as small ASCII-art pictures, similarly to OpenSSH's randomart.

This allows easier verification by humans but may not be as secure as a bytewise comparison of the digest!

See the paper [Hash Visualization: a New Technique to improve Real-World Security¹][^1] for more information on the concept of random art.

The paper [The drunken bishop: An analysis of the OpenSSH fingerprint visualization algorithm²][^2] analyses the OpenSSH implementation in more detail.

It should be explicitly noted that my algorithm is similar but not identical to the "drunken bishop" walk of the OpenSSH implementation. The implementation at hand:

• flips sides at the borders, which turns the field into a torus
• moves in all possible directions with distance 1, not only diagonally
• does not mark start (S) and end (E) and uses a different character palette

I have not performed any similar analysis[²][^2] but would expect my implementation to perform no worse.

installation

Install the latest version with pip directly from GitHub:

pip install git+https://github.com/ansemjo/randomart

Or from PyPI:

pip install randomart

usage

The script expects a file in the first positional argument or otherwise simply reads from standard input. It is thus best suitable for usage in a pipe:

echo 'Hello, World!' | randomart.py

There are two flags to control the output:

• --ascii use only ASCII characters for the box frame
• --hash - print the computed digest before the randomart picture

Otherwise use randomart.py --help for usage help.

as a library

If you want to use your own hash you can import from random_art.randomart:

from random_art.randomart import draw, drunkenwalk
...

# generate your hash digest
digest = ...

# generate randomart, HASHNAME must be 10 characters
art = draw(drunkenwalk(digest), HASHNAME)
print(art)

[^1]:

http://www.ece.cmu.edu/~adrian/projects/validation/validation.pdf "Perrig A. and Song D., 1999, International Workshop on Cryptographic Techniques and E-Commerce (CrypTEC '99)"

[^2]:

http://www.dirk-loss.de/sshvis/drunken_bishop.pdf "Dirk Loss, Tobias Limmer, Alexander von Gernler, 2009"