X.509 key set

[mentoc3000]

I am trying to use jose for Firebase JWT verification. The public keys are provided here and look like this:

{
  "063a7ca43c3c7603674eda4be97725b73d0dc01f": "-----BEGIN CERTIFICATE-----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\nWv1e7z+r9USe5nycawEH/1/98OfL6d7KD75QjXywZE8=\n-----END CERTIFICATE-----\n",
  "1af60c17e2d6f8ad534c400c5a16d676fad777e6": "-----BEGIN CERTIFICATE-----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\nNEAraaVQ4GbkIgjBJpwzJ0QgGeqDbIREXQX8HgOSiFw=\n-----END CERTIFICATE-----\n"
}

The Firebase documentation defines the algorithm: RS256. I have succeeded in verifying an example JWT by importing the hardcoded key using importX509 and passing the result and the JWT to jwtVerify.

Now I would like to use createRemoteJWKSet but I am struggling. From the documentation it looks like the expected format of the data from the URL, based on the example, is different from what I have. Is it possible to use createRemoteJWKSet with this source of keys?

[panva]

It has to be a JSON Web Key Set. Proprietary key formats are, well, proprietary and not interoperable.