[openpgp] encrypting textual data with sop [was: Re: text vs. binary in an OpenPGP "Signed Message" ]

[Daniel Kahn Gillmor <[e-mail]>]

Thanks for the response, Daniel--

I'm hoping the rest of this thread can ignore the additional complexity
of the encryption wrapping on the thread more generally, but i just
wanted to address this point.

On Sat 2025-02-22 14:52:52 +0000, Daniel Huigens wrote:
> Unfortunately they don't tell us much about GnuPG's behavior since the
> SOP layer doesn't seem to support inline-verify nor text signatures
> inside encrypted data, weirdly enough.

`sop encrypt` has an option `--as={text|binary}`, which should apply in
conjunction with `--sign-with=KEYS`.

https://www.ietf.org/archive/id/draft-dkg-openpgp-stateless-cli-13.html#section-5.4.3-7
says:

>>> If --as is set to binary, then --sign-with will sign as a binary
>>> document (OpenPGP signature type 0x00).
>>> 
>>> If --as is set to text, then --sign-with will sign as a canonical
>>> text document (OpenPGP signature type 0x01). In this case, if the
>>> input DATA is not valid UTF-8 (Section 11.7), sop encrypt fails with
>>> EXPECTED_TEXT.

So producing text signatures inside encrypted data should be supported
by any sop implementation.

   --dkg