Node silently allows using dh and x25519 keys for signing / verification

[lucacasonato]

Version

v22.4.0

Platform

Linux pop-os 6.9.3-76060903-generic #202405300957171834820922.04~7817b67 SMP PREEMPT_DYNAMIC Mon J x86_64 x86_64 x86_64 GNU/Linux

Subsystem

crypto

What steps will reproduce the bug?

import crypto from 'node:crypto';

const { privateKey, publicKey } = crypto.generateKeyPairSync('x25519', {});

const sign = crypto.createSign('sha512');
sign.update('some data to sign');
sign.end();
const signature = sign.sign(privateKey);
console.log('Signature:', signature.toString('hex'));

const verify = crypto.createVerify('sha512');
verify.update('some data to sign');
verify.end();
console.log('Verify:', verify.verify(publicKey, signature));

Produces output like:

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

Node throws an error that x25519 keys can not be used for signing. Same should happen for dh keys.

What do you see instead?

Signature: 8603053600000000000000000000000000930436000000000000000000000000
Verify: false

(invalid output)

Additional information

No response

[avivkeller]

@nodejs/crypto PTAL