wycheproof-ecdh-wrong-curve

ECDH: Wrong curve

The public key and private key use distinct curves. Implementations are expected to reject such parameters.

REJECT

Your service should reject this one.

Stated as the outcome to assert against, so a suite compares with this rather than hardcoding a result and getting it backwards.

Computing an ECDH key exchange with public and private keys can in the worst case lead to an invalid curve attack. Hence, it is important that ECDH implementations check the input parameters. The severity of such bugs is typically smaller if an implementation ensures that the point is on the curve and that the ECDH computation is performed on the curve of the private key. Some of the test vectors with modified public key contain shared ECDH secrets, that were computed over the curve of the private key. Demonstrated by 345 test vectors across 20 vector documents in Project Wycheproof.

Provenance

Kind
vulnerabilityA published weakness exists for this. Failing it is a known exploit path.
Source
wycheproof
Clause
SEC 1 §3.3
CVE
none
Weakness
none

Test keys only. Nothing here is a statement about any particular service: the expected outcome above is what an application ought to do, not evidence that yours does.

Reference

URL or embedded key?

Your app needs the public key to check a token. It can fetch it from a URL at runtime, or carry it as a file. Both are normal. The trade is always the same one: who controls rotation.

Fetch from the URLEmbed the key
RotationAutomatic on next fetchNeeds a redeploy
NetworkDepends on the URLNone
TrustWhatever the endpoint servesPinned to one key
SuitsA signer that rotates keysOffline, air-gapped, or pinned

Use the URL when the signer rotates its keys, which is what every identity provider does. That is why it became the norm, and it is usually a one-line config change.

Embed the key when you cannot make a network call while checking a token, or when you want your app pinned to one key so a compromised endpoint could not introduce another. Export the PEM from the Keysets tab.

One catch worth knowing: Spring Boot's public-key-location only loads RSA keys. An ES256 or EdDSA key needs a custom decoder, or the URL.