[leifj]

Summary

Fixes the two certificates left unparsed by the ecparams Master List run (#36), both opt-in (nothing changes unless ecparams.Register is called):

1. Zero-padded curve constants. The curve constants A and B are compared as integers, so a leading 0x00 pad (49-byte A/B on P-384, UAE CSCA 02) still matches the known curve. Every value must still equal the known number exactly. The Verifier path re-derives the key on the table curve and handles the certificate (tested).
2. Non-DER cA BOOLEAN. A basicConstraints extension whose cA BOOLEAN is BER-style TRUE (any non-zero octet, e.g. 0x01 in CSCA-UKRAINE) is normalised to 0xFF for the stdlib parse only. Same-length patch of that one octet in a copy; the original extension value, Raw, RawTBSCertificate, Signature are restored, nothing is re-encoded in the result.

What stays rejected

• Unknown curves and any non-matching A/B/prime/order/cofactor/generator, with or without padding (tested on P-384 and brainpoolP384r1); padding on the base point.
• Malformed basicConstraints is never repaired: truncated, BOOLEAN of wrong length, non-BOOLEAN cA, trailing data, bad pathLen. The plugin never changes the stdlib verdict for these.
• Tampered variants of both real certificates (changed constants, cA, signature, TBS).

Tests

Hand-built padded-A/B certificates on all 7 curves (P-384 and a brainpool curve included) parse and verify; BER-boolean certificates (named curve, explicit params, with pathLen); both real CSCAs added to ecparams/testdata with provenance headers (sha256 checked in the test); fuzz seeds extended (fuzzed 30s, no findings). ecparams coverage 97.2%; golangci-lint/vet/gofmt clean.

Real numbers (BSI German Master List, 608 certificates)

Before: 606 parsable, 2 failing. After:

certificates: 608
stdlib parsable: 433; rejected: 175
parsable with extensions: 608; still failing: 0
explicit-parameter keys recovered, by curve: P-256=24; P-384=31; P-521=22; brainpoolP256r1=22; brainpoolP384r1=54; brainpoolP512r1=17
deliberately declined explicit-parameter certificates: {}
self-signed certificates verified: 386 of 386

Docs: ecparams package doc and README section updated.

Note for release: v0.7.1

Closes #36

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟡 Changes recommended

Some fuzz seeds cannot reach the intended parser path, and public documentation overstates the accepted padding behavior.

Review effort: Balanced
Findings: 1

Open (1)

• Limit documentation claim to A and B parameters · New

What changed in this PR

Adds opt-in support for padded EC constants and BER-style basicConstraints booleans.

Changes:

• Compares EC constants numerically.
• Normalizes non-DER cA booleans while preserving original bytes.
• Adds fixtures, tests, fuzz seeds, and documentation.

File	Description
README.md	Documents accepted encodings.
ecparams/​ecparams.go	Implements normalization and numeric comparison.
ecparams/​helpers_test.go	Extends certificate test builders.
ecparams/​padding_bool_test.go	Adds regression and tampering tests.
ecparams/​fuzz_test.go	Adds fuzz seeds.
ecparams/​testdata/​csca_are_padded_constants.pem	Adds UAE certificate fixture.
ecparams/​testdata/​csca_ukr_ber_boolean.pem	Adds Ukraine certificate fixture.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

Copilot review overview

🟢 Approval recommended

The implementation is narrowly scoped, preserves original signed data, and thoroughly tests valid and malformed cases.

Review effort: Balanced
Findings: None

Resolved since last review (1)

• Limit documentation claim to A and B parameters