curl --request POST \
  --url https://api.dfns.io/auth/credentials/code/init \
  --header 'Content-Type: application/json' \
  --data '
{
  "credentialKind": "Fido2",
  "code": "<string>"
}
'

{
  "kind": "Fido2",
  "user": {
    "id": "<string>",
    "displayName": "<string>",
    "name": "<string>"
  },
  "challengeIdentifier": "<string>",
  "challenge": "<string>",
  "authenticatorSelection": {
    "residentKey": "required",
    "requireResidentKey": true,
    "userVerification": "required",
    "authenticatorAttachment": "platform"
  },
  "attestation": "none",
  "pubKeyCredParams": [
    {
      "type": "public-key",
      "alg": 123
    }
  ],
  "excludeCredentials": [
    {
      "type": "public-key",
      "id": "cr-6uunn-bm6ja-f6rmod5kqrk5rbel"
    }
  ],
  "temporaryAuthenticationToken": "<string>",
  "rp": {
    "id": "<string>",
    "name": "<string>"
  }
}