Original author here -- thanks to everyone for the feedback. Some time has passed since this was originally written and the remaining languages were never updated to improve the safety of the signature verifications.

The original reasoning behind this post was to provide a single reference for signature generation and verification in some common languages -- something I struggled to locate myself. Admittedly, I should've provided warnings about using simple and hardcoded keys in the examples, which were done that way for readability.

While there is still a lot of debate about the ability to perform true constant-time comparisons in many of these languages (https://bugs.python.org/issue15061, https://github.com/joyent/node/issues/8560) I agree that for those who would be otherwise using the unsafe string comparisons, the benefits certainly outweigh the slightly added complexity.

The updated gists are available in the post to anyone with comments or improvements.

Cheers!