> On Feb 19, 2016, at 2:18 PM, Paul Wouters <paul@xxxxxxxxx> wrote: > > I do not understand how the process of a plaintext email that goes > through this document's advice, and leaves as either still plaintext > or encrypted, could be construed as a "cryptographic downgrade". RFC7435 has not been read attentively, or perhaps is viewed as heresy: https://tools.ietf.org/html/rfc7435#section-1.2 "Opportunistic Security" (OS) is defined as the use of cleartext as the baseline communication security policy, with encryption and authentication negotiated and applied to the communication when available. Cleartext, not comprehensive protection, is the default baseline. An OS protocol is not falling back from comprehensive protection when that protection is not supported by all peers; rather, OS protocols aim to use the maximum protection that is available. -- Viktor.