Yes, informal standards, but that's exactly the problem. At my previous work, I've implemented something similar to Fernet in the past (though using AES-GCM rat

Yes, informal standards, but that's exactly the problem. At my previous work, I've implemented something similar to Fernet in the past (though using AES-GCM rather than AES-CBC+HMAC), and that's dead simple. But it's not standard. Every time I've suggested modifying our JWT implementation to use Ed25519, or using any NaCL implementation for encryption instead of the vulnerability-footgun framework better known as JCE, I get raised eyebrows. People want standards. Fernet is nice, but it should be pushed to an RFC level and offer more metadata besides a timestamp (not hard, just copy all the JWT claim names in stick a JSON into the ciphertext :)) It's also not useful when you do need asymmetric encryption/signature, and you can't just ignore these use cases, since people will keep JWT alive just for them.