generateKeyPair return object with empty field

[giovanni9793]

I don't know if I'm doing something wrong, but the function generateKeyPair does not work for me, but it seems a problem with crypto because also the following code return the same object:

import generateKeyPair from 'crypto'
import { promisify } from 'util'

const keys = promisify(generateKeyPair.generateKeyPair)
        console.log(
          JSON.stringify(
            await keys('rsa', {
              modulusLength: 2048,
              publicExponent: 0x10001,
            }),
          ),
        )

output:

{"publicKey":{},"privateKey":{}}

The code was runned on a docker machine with node 14.

[panva]

That's expected.

> JSON.stringify(crypto.generateKeyPairSync('ed25519'))
'{"publicKey":{},"privateKey":{}}'
> console.log(crypto.generateKeyPairSync('ed25519').privateKey)
PrivateKeyObject { [Symbol(kKeyType)]: 'private' }

See KeyObject docs.

[giovanni9793]

EDIT, same behaviour also with await
>console.log((await crypto.generateKeyPairSync('ed25519')).privateKey)
[object Object]
>console.log(JSON.stringify((await crypto.generateKeyPairSync('ed25519')).privateKey))
{}

Is it expected? If yes, how can I know what is the key since also "fromKeyLike" print "{}"?

>console.log( 'Private: ',JSON.stringify(fromKeyLike(private_key)))
Private: {}

[panva]

Yes it is expected. You're stringifying the return of fromKeyLike which is a Promise, one that is resolved with a JWK object.

[giovanni9793]

Ok, thank you for the docs, so the code to use to show the private key that I have created with generateKeyPair is:

const { privateKey } = await generateKeyPair('RS256', {
          modulusLength: 2048,
        })

console.log(
  JSON.stringify(
    (privateKey as KeyObject).export({
      type: 'pkcs1',
      format: 'pem',
    }),
  ),
)

instead if I have a RSA key a could use crypto.createPrivateKey to obtain a KeyLike, so now that i have it I can use

id_token = await new SignJWT(baseJwt)
                  .setProtectedHeader({ alg: 'RS256' })
                  .sign(privateKey)