{
 "alg": "Ed25519",
 "key_id": "k1",
 "public_key_b64_raw": "Doce6wjV9P+E6Eigbf8fmSJtbcokJwjzSSrvLOkjVo4=",
 "canonical_url": "https://toolwork.org/.well-known/toolwork-signing-key.json",
 "signed_message": "`${x-toolwork-signed-at}\\n${response body}` (exact response body bytes)",
 "header": "x-toolwork-signature (base64), x-toolwork-signed-at, x-toolwork-key-id"
}