doc: clarify x509.checkIssued only checks metadata

PR-URL: #58457
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>

Author: panva

doc/api/crypto.md

@@ -2647,7 +2647,23 @@ added: v15.6.0
 * `otherCert` {X509Certificate}
 * Returns: {boolean}
 
-Checks whether this certificate was issued by the given `otherCert`.
+Checks whether this certificate was potentially issued by the given `otherCert`
+by comparing the certificate metadata.
+
+This is useful for pruning a list of possible issuer certificates which have been
+selected using a more rudimentary filtering routine, i.e. just based on subject
+and issuer names.
+
+Finally, to verify that this certificate's signature was produced by a private key
+corresponding to `otherCert`'s public key use [`x509.verify(publicKey)`][]
+with `otherCert`'s public key represented as a [`KeyObject`][]
+like so
+
+```js
+if (!x509.verify(otherCert.publicKey)) {
+  throw new Error('otherCert did not issue x509');
+}
+```
 
 ### `x509.checkPrivateKey(privateKey)`
 
@@ -6187,6 +6203,7 @@ See the [list of SSL OP Flags][] for details.
 [`verify.update()`]: #verifyupdatedata-inputencoding
 [`verify.verify()`]: #verifyverifyobject-signature-signatureencoding
 [`x509.fingerprint256`]: #x509fingerprint256
+[`x509.verify(publicKey)`]: #x509verifypublickey
 [caveats when using strings as inputs to cryptographic APIs]: #using-strings-as-inputs-to-cryptographic-apis
 [certificate object]: tls.md#certificate-object
 [encoding]: buffer.md#buffers-and-character-encodings