Token encryption cannot replace TLS. See #64

[ioggstream]

This PR

• token encryption can't replace TLS unless similar requirements are implemented (integrity, privacy, authenticity) ;
• suggest using TLS along the way, even when using TLS terminators;
• MUST does not define here a specific requirement

Note

Some mitigation measure express strict requirements (e.g. MUST NIT store in insecure cookies). IMHO that's ok, but in this case it's more than mitigation, since an implementation that does not respect these is non conformant.

[tlodderstedt]

I agree that token encryption is not a replacement for TLS. Encryption should be used to prevent any party along the way from AS to RS to inspect the data in the token, including the client.
Similar, signatures protect the integrity and authenticity of self-contained tokens along the way, especially at the client.
Lack of TLS protection from datacenter edge to RS could cause only problems with sender constrained access tokens bound to a TLS certificate. I think the suitable solution would be to use DPoP instead of Client TLS authentication in such cases.