Correct RS256 keypair keeps throwing: secretOrPrivateKey must be a symmetric key when using HS256

[roelvanhintum]

Describe the bug
While using a correct keypair (accoirding to https://jwt.io/ set to RS256) i keep getting the following error:
secretOrPrivateKey must be a symmetric key when using HS256

Generated the keys with the following commands:

openssl genrsa -out jwtRSA256-private.pem 2048
openssl rsa -in jwtRSA256-private.pem -pubout -outform PEM -out jwtRSA256-public.pem

Expected behavior
Normal login using saLTIre.

Provider logs

2023-12-07T15:14:57.393Z provider:main Receiving request at path: /lti/login
2023-12-07T15:14:57.393Z provider:main Receiving a login request from: https://saltire.lti.app/platform, clientId: saltire.lti.app
2023-12-07T15:14:57.396Z provider:main Redirecting to platform authentication endpoint
2023-12-07T15:14:57.396Z provider:main Target Link URI:  https://myurl.example/lti
2023-12-07T15:14:57.397Z provider:main Login request: 
2023-12-07T15:14:57.399Z provider:main {
  response_type: 'id_token',
  response_mode: 'form_post',
  id_token_signed_response_alg: 'RS256',
  scope: 'openid',
  client_id: 'saltire.lti.app',
  redirect_uri: 'https://myurl.example/lti',
  login_hint: '29123',
  nonce: 'dhbtgbyhs1s2h2fjm5vwn8ftf',
  prompt: 'none',
  state: 'e58b660afb9f0b4ef75aece82f50491e6fd6c14a8df083cdd1',
  lti_message_hint: 'My LTI message hint!',
  lti_deployment_id: 'cLWwj9cbmkSrCNsckEFBmA'
}
2023-12-07T15:14:57.842Z provider:main Receiving request at path: /lti/
2023-12-07T15:14:57.842Z provider:main Path does not match reserved endpoints
2023-12-07T15:14:57.842Z provider:main Cookies received: 
2023-12-07T15:14:57.842Z provider:main [Object: null prototype] {
  statee58b660afb9f0b4ef75aece82f50491e6fd6c14a8df083cdd1: 'https://saltire.lti.app/platform'
}
2023-12-07T15:14:57.842Z provider:main Received idtoken for validation
2023-12-07T15:14:57.842Z provider:auth Response state: e58b660afb9f0b4ef75aece82f50491e6fd6c14a8df083cdd1
2023-12-07T15:14:57.846Z provider:auth Attempting to validate iss claim
2023-12-07T15:14:57.846Z provider:auth Request Iss claim: https://saltire.lti.app/platform
2023-12-07T15:14:57.846Z provider:auth Response Iss claim: https://saltire.lti.app/platform
2023-12-07T15:14:57.846Z provider:auth Attempting to retrieve registered platform
2023-12-07T15:14:57.857Z provider:auth Retrieving key from jwk_set
2023-12-07T15:14:58.248Z provider:auth Converting JWK key to PEM key
2023-12-07T15:14:58.250Z provider:auth Attempting to verify JWT with the given key
2023-12-07T15:14:58.254Z provider:auth Token signature verified
2023-12-07T15:14:58.255Z provider:auth Initiating OIDC aditional validation steps
2023-12-07T15:14:58.255Z provider:auth Validating if aud (Audience) claim matches the value of the tool's clientId given by the platform
2023-12-07T15:14:58.255Z provider:auth Aud claim: saltire.lti.app
2023-12-07T15:14:58.255Z provider:auth Checking alg claim. Alg: RS256
2023-12-07T15:14:58.255Z provider:auth Max age parameter:  10
2023-12-07T15:14:58.255Z provider:auth Checking iat claim to prevent old tokens from being passed.
2023-12-07T15:14:58.255Z provider:auth Iat claim: 1701962097
2023-12-07T15:14:58.255Z provider:auth Exp claim: 1701962157
2023-12-07T15:14:58.255Z provider:auth Current_time: 1701962098.255
2023-12-07T15:14:58.255Z provider:auth Time passed: 1.255000114440918
2023-12-07T15:14:58.255Z provider:auth Validating nonce
2023-12-07T15:14:58.255Z provider:auth Nonce: dhbtgbyhs1s2h2fjm5vwn8ftf
2023-12-07T15:14:58.256Z provider:auth Tool's clientId: saltire.lti.app
2023-12-07T15:14:58.256Z provider:auth More than one aud listed, searching for azp claim
2023-12-07T15:14:58.260Z provider:auth Storing nonce
2023-12-07T15:14:58.272Z provider:auth Initiating LTI 1.3 core claims validation
2023-12-07T15:14:58.272Z provider:auth Checking Message type claim
2023-12-07T15:14:58.272Z provider:auth Checking Target Link Uri claim
2023-12-07T15:14:58.272Z provider:auth Checking Resource Link Id claim
2023-12-07T15:14:58.272Z provider:auth Checking LTI Version claim
2023-12-07T15:14:58.272Z provider:auth Checking Deployment Id claim
2023-12-07T15:14:58.272Z provider:auth Checking Sub claim
2023-12-07T15:14:58.272Z provider:auth Checking Roles claim
2023-12-07T15:14:58.274Z provider:auth Successfully validated token!
2023-12-07T15:14:58.289Z provider:main Generating ltik
2023-12-07T15:14:58.290Z provider:main Deleting state cookie and Database entry
2023-12-07T15:14:58.293Z provider:auth Error: secretOrPrivateKey must be a symmetric key when using HS256
    at module.exports [as sign] (/usr/src/app/node_modules/jsonwebtoken/sign.js:127:20)
    at sessionValidator (/usr/src/app/node_modules/ltijs/dist/Provider/Provider.js:425:33)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
2023-12-07T15:14:58.293Z provider:main Passing request to invalid token handler

Ltijs version

• Version 5.9.3

NodeJS version

• v21.1.0

Platform used

• https://saltire.lti.app/platform