RustCrypto / RustCrypto/traits

elliptic-curve: Use a single `Point` type instead of `AffinePoint` and `ProjectivePoint`

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elliptic-curve
Dominant language
Rust
Stars
755
Forks
256
Avg merge
1h 27m
Merged PRs (30d)
2

Description

As discussed in https://github.com/dalek-cryptography/curve25519-dalek/pull/746#issuecomment-2909894366. AffinePoint and ProjectivePoint weakly map to some elliptic curve implementations. Some implementations don't use the projective variant of their points (thinking of montgomery curves) and some only use the projective or another variant of point. For example, ed25519 uses points in $\mathbb{P}^1 \times \mathbb{P}^1$ space.

We might be able to construct a better abstraction for elliptic-curves by only using a single Point associated type. I am writing this here to stir up thoughts & opinions around this idea.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the linked discussion and locating the existing AffinePoint and ProjectivePoint traits or types in the repository. The issue does not identify files, tests, or a settled target design, so done would require agreeing on a replacement abstraction and updating the affected cryptographic traits and tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
cryptography
Issue type
Refactor
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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