Repository navigation
Reuse field inversions in Shamir recovery and division - #2558
Open
carstenartur wants to merge 1 commit into
Open
carstenartur wants to merge 1 commit into
carstenartur wants to merge 1 commit into
Conversation
Accumulate interpolation numerator and denominator products before inverting, and reuse an inverse within each share row during division. Keep the original paths for Polynomial subclasses and small inputs. Add scaling and overridden-division regression coverage. Identified with the Sandbox mathematics cleanup: https://github.com/carstenartur/sandbox AI-assisted preparation and review.
There was a problem hiding this comment.
🟢 Approval recommended
No active review issues block the change to reduce repeated finite-field inversions.
No open issues 🎉
What changed in this PR
This PR reduces repeated finite-field inversions in Shamir secret recovery and share division while preserving the existing API and fallback behavior for Polynomial subclasses and small inputs.
Changes:
- Combine interpolation products to use one inversion per recovery coefficient.
- Reuse one inverse per eligible share row during division.
- Add scaling and overridden-division regression tests to the threshold suite.
| File | Description |
|---|---|
core/src/test/java/org/bouncycastle/crypto/threshold/test/ShamirSecretSplitterTest.java |
Tests recovery after scaling shares and dividing them back. |
core/src/test/java/org/bouncycastle/crypto/threshold/test/AllTests.java |
Registers the new subclass regression tests. |
core/src/test/java/org/bouncycastle/crypto/threshold/ShamirSplitSecretTest.java |
Verifies recovery and division preserve overridden division behavior. |
core/src/main/java/org/bouncycastle/crypto/threshold/ShamirSplitSecret.java |
Reuses inversions in recovery and division, retaining fallback paths. |
Review effort: Balanced
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Reduce repeated field inversions in ShamirSplitSecret.getSecret() and divide(), preserving the existing API.
Verification at upstream e40316b:
The full Gradle/core suite, Checkstyle and JMH were not run for this submission. Counts above refer to field inversions, not a measured runtime speedup.
Identified by the Sandbox mathematics cleanup:
https://github.com/carstenartur/sandbox
Sandbox qualification:
https://github.com/carstenartur/sandbox/actions/runs/42453057191/job/128646172609
Generated source was adapted for naming, comments and formatting while preserving its guards, masks, fallback paths and per-row schedule. ChatGPT assisted with preparation, regression tests and review.