nim-groth16/groth16/dynamic/README.md

"Semi-dynamic" Groth16 proofs

This is loosely based on the Dynark paper:

• "Dynark: Making Groth16 Dynamic" by Tianyu Zhang, Yupeng Ouyang and Yupeng Zhang

See also this write-up (mostly following the paper).

Here some details are different from the paper though, and our implementation is noticeably more efficient in practice.

Different versions

We provide several slightly different versions with different tradeoffs

• dynamic/v1: This is a version mostly following the Dynark paper
  • TODO: sparse convolution algorithm
• dyanmic/v2: This introduces some of our optimizations:
  • the projection term updates become essentially free
  • micro-optim: concatenate all the pi_C MSMs into one
• dyanmic/v3:
  • we reorder the circuit so that the changes are in a subgroup
  • so cross-terms becomes O(D*log(D), and also just 1 MSM instead of 2
  • so the updates now are essentially optimal
  • TODO: half of the very slow group FFTs (during the slow preprocessing step) also becomes O(D*log), so that's essenitally a 2x speedup