ios – Is there a technique to decode a ES256 encoded JWT with a root certificates however with no public key or a non-public key?

I am receiving JWT from Apple for In-App-Purchases and want to confirm them once I decode them.

I am utilizing ruby (with ruby on rails) so I do:

JWT.decode(params[:signedPayload], nil, true, { algorithm: 'ES256', root_certificates: root_certificates })

I get the foundation certificates from https://www.apple.com/certificateauthority

• Apple Inc. Root
• Apple Laptop, Inc. Root
• Apple Root CA – G2 Root
• Apple Root CA – G3 Root

And the payload is base64 encoded JWT, however decoded it seems one thing like:

{
  "notificationType": "DID_CHANGE_RENEWAL_PREF",
  "subtype": "UPGRADE",
  "notificationUUID": "386fe04a-7caf-40b1-91ca-a4e29f2d135f",
  "information": {
    "bundleId": "com.socializusapp",
    "bundleVersion": "73",
    "surroundings": "Sandbox",
    "signedTransactionInfo": "eyJhbGciOiJFUzI1NiIsIng1Y...",
    "signedRenewalInfo": "eyJhbGciOiJFUzI1NiIsIng1Yy..."
  },
  "model": "2.0",
  "alg": "HS256"
}

How can I confirm the payload is right? I attempted one other non-public key I take advantage of for apple register however would not work

Possibly I need not confirm and I can simply decode the signed fields? However then how do I decode them?