Tool for generating sha256 initializiation with fixed midstate from BIP340 tagged hash #1653

1. 
   theStack commented at 6:12 pm on February 8, 2025: contributor

   New secp256k1 modules often take use of BIP340 tagged hashes, with corresponding functions to initialize _sha256 objects with a fixed midstate for efficiency reasons. Right now there seems to be no standard way to create these functions, presumably every contributor does this in a slightly different way (I guess all ways involve cluttering the code with printf statements though). I was wondering if it’s worth it to provide a small tool for that, which could also be useful for reviewing.

   Proof-of-concept (not involving the build system yet): https://github.com/theStack/secp256k1/commit/009cac68a3bb571901636809183778bc70caf260

2. real-or-random added the label meta/development on Feb 24, 2025
3. 
   real-or-random commented at 2:45 pm on February 24, 2025: contributor

   Last time I needed this, I used this Python library: https://github.com/cloudtools/sha256. I believe that’s a bit simpler than maintaining a C program (with build system integration, etc.)

   Of course, we could also add a small Python snippet that prints a BIP340 midstate explicitly.

Contributors
theStack real-or-random

Labels
meta/development