Ritual-
Tampering with share 2 changes one bit. Verification fails for exactly that index, and reconstruction over a quorum containing it returns a different secret - which is why the commitment exists.
Below threshold, nothing is learned
Three different hypothesised secrets, each extended with the same two observed shares, produce polynomials that agree with both observations and disagree about every further coordinate. A holder of two shares cannot choose between them.
Reproduce
python -m pytest -q # 14 tests
python -m sharelock.demo runs/demo.json # records this page
python -m bench.bench # timings in the report
# typeset the paper
pdflatex docs/report.tex && pdflatex docs/report.tex
The report is committed in LaTeX (docs/report.tex) with a prebuilt PDF (docs/report.pdf) for reviewers without a TeX installation. Security claims are stated as theorems with proofs, not as benchmarks.