Refactor EC key padding length lookup into shared cryptoECC helper; add BN-254 support

[ljoy913]

PR #25’s leading-zero padding logic introduced four duplicated curve-length tables in ECDH/ECDSA, and all four omitted BN-254. This change consolidates curve element-length resolution into a single shared source and makes lookups case-insensitive to avoid drift and mismatches.

• Shared curve element-length source in cryptoECC

  • Added curveElementLengths in src/cryptoECC.js with the full supported set, including "BN-254": 32.
  • Added/exported cryptoECC.curveElementLength(curveName) to normalize via toUpperCase() and return the fixed element byte length.

• Replaced duplicated partLen tables (4 call sites)

  • src/ecdh.js
    • generateKey
    • importKey (p.format === "jwk")
  • src/ecdsa.js
    • generateKey
    • importKey (p.format === "jwk")
  • Each now reads from cryptoECC.curveElementLength(...) instead of inline object literals.

• Targeted BN-254 coverage updates in existing ECC tests

  • Added BN-254 key-generation test cases in test/Test.Ecdh.js and test/Test.Ecdsa.js.
  • Updated test key-length checks to use cryptoECC.curveElementLength(...) directly instead of duplicated ecdhKeyLengths / ecdsaKeyLengths tables.

• Rebuilt distribution bundle

  • Regenerated dist/msrcrypto.js and dist/msrcrypto.min.js so the published bundle includes the fix.

Example of the lookup change:

// before
var partLen = {
    "P-256": 32, "P-384": 48, "P-521": 66,
    "NUMSP256D1": 32, "NUMSP256T1": 32,
    "NUMSP384D1": 48, "NUMSP384T1": 48,
    "NUMSP512D1": 64, "NUMSP512T1": 64
}[p.algorithm.namedCurve];

// after
var partLen = cryptoECC.curveElementLength(p.algorithm.namedCurve);

[Copilot]

Pull request overview

This PR centralizes ECC curve element byte-length resolution into cryptoECC to eliminate duplicated per-curve tables in ECDH/ECDSA padding logic, and extends that shared lookup to include BN-254 (32-byte elements). It also updates the QUnit ECDH/ECDSA tests to cover BN-254 and to reference the shared helper, and regenerates the distribution bundle accordingly.

Changes:

• Added cryptoECC.curveElementLength(curveName) (case-insensitive) and a shared curveElementLengths table including "BN-254": 32.
• Updated ECDH/ECDSA generateKey and JWK importKey padding logic to use cryptoECC.curveElementLength(...) instead of inline tables.
• Added BN-254 generateKey coverage in ECDH/ECDSA tests and removed duplicated test-side curve-length tables.

Reviewed changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/cryptoECC.js	Introduces shared curve element-length lookup (including BN-254) and exports it from cryptoECC.
src/ecdh.js	Replaces inline curve-length table with cryptoECC.curveElementLength(...) for key padding in generate/import (JWK).
src/ecdsa.js	Replaces inline curve-length table with cryptoECC.curveElementLength(...) for key padding in generate/import (JWK).
test/Test.Ecdh.js	Adds BN-254 generateKey test and switches length assertions to the shared helper.
test/Test.Ecdsa.js	Adds BN-254 generateKey test and switches length assertions to the shared helper.
dist/msrcrypto.js	Regenerated bundle reflecting the shared helper + call-site updates.

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