There's a discussion thread for email attestations here[1]. Those would support local builds.
But to take a step back: if you want attested builds because you think attestation is itself a gold star, then you're working from the wrong priors. Attestations do not imply that a package is secure any more than a hash does; what they are is a cryptographic signature over a set of claims, which allows for authenticated auditing of a project's state over time.
I think PyPI's documentation does a good job of conveying this nuance[2], and that much of the opprobrium of attestations comes from people either not understanding that nuance or imputing conspiracies into it.
[1]: https://github.com/pypi/warehouse/issues/18007
[2]: https://docs.pypi.org/attestations/security-model/#trustwort...
> what they are is a cryptographic signature over a set of claims, which allows for authenticated auditing of a project's state over time.
Which is great--but does not in any way require that the attestation can only be produced by working through one of a small set of recognized "forges". You could do this just as easily by, for example, letting me upload to my PyPI account a public key (the same as forges like Github do to allow SSH access), and then letting me sign builds that I upload using the corresponding private key. But that kind of workflow is not being supported. Why not?
> Which is great--but does not in any way require that the attestation can only be produced by working through one of a small set of recognized "forges"
That's true, there's some context elsewhere in these threads about how PyPI can enable email attestations. The short version is that PyPI wanted to make this work by default, which was trivial with Trusted Publishing (since it already provides a strong source of verifiable machine identity).
"Why not a public key?" is a good question, and the very short answer is that greenfield signing designs should not assume that all users are able to manage the secrecy of long-lived key materials, much less force them to make parameter decisions when (re)generating materials. This is the same mistake that the Web PKI made for decades, and has spent the last 15 years slowly untangling. The ideal setup is one where users demonstrate control over an identity, and then the signing scheme binds that identity to a short-lived signing key. That's how email attestations work.
> email attestations
From what I can gather from the github issue that was linked to, those would still require the email identity to be vouched for by a provider. (Though if whoever already is hosting my email could be a "provider", that would at least greatly expand the list of providers from the current small number of forges.) There doesn't seem to be any way for me to, for example, link a public key I generate myself to an email address that PyPI already has on file for me.
Have you considered that perhaps you are working from the wrong priors?
I believe your prior is that you expect people who read the PyPI page to understand what attestation means. I believe your prior is they will see a notice about "not from a trusted publisher" and not treat it like demerit or warning. I believe your prior is that seeing this message will get people to do more due diligence than they currently do, and that the due diligence will be relevant and appropriate.
Based on my experience with my users, I don't have the same confidence.
I don't understand what "authenticated auditing" means, so why should they?
What project state do people think is important to audit? My code repo is private, hosted on Sourcehut. My build system is private, done locally. The only thing I release is the pre-built binary package. There's very little state to examine, and I can't figure out why anyone cares.
I also have customers who buy a source code license. They have never asked for an audit of the project's state over time.
I read the "Security model and considerations" document. I found it opaque, no doubt because the entire topic is foreign to me, but it doesn't do a good job of explaining. Take the second paragraph:
"The most basic type of attestation (the type enabled by default in pypa/gh-action-pypi-publish) asserts that the project was published by an authorized publisher such as a particular CI provider in a particular code repository.".
I know pypa/gh-action-pypi-publish is some sort of GitHub thing. I don't use GH or third-party CI so that clarification does not help.
It doesn't describe what "authorized publisher" means, other than a generic example of "particular CI provider in a particular code repository". That phrase exists only once in the document. Is it different from a "Trusted Publisher"?
Why are the terms "authorized" and "Trusted" used, instead of something like "affiliated"? If someone is not a trusted publisher or an authorized publisher it's is too easily misinterpreted as "untrusted publisher" or "unauthorized publisher", which seems scary. If someone is not an affiliated publisher, "unaffiliated publisher" sounds less scary. (I'm not saying "affiliated" is the right word, only an example of a roughly appropriate word where the negation of it is not so scary.)
Then later, "It protects against modification of a project after it was built".
I think that's supposed to be "modification of a release after it was built"?
My use of "project" matches the one at https://docs.pypi.org/using-pypi/pypi-basics/ "A project is a collection of releases and files, and information about them. ... A "release" on PyPI is a specific version of a project." I want to modify the project with updated metadata as things change, and to make new releases.
Oh, and I can't find a description of what "build" means in that document. It's used as if everyone expects to know what it means, but a few years ago I learned that modern Python packaging uses "build" different than I do.
When I compile my Python/C extension I "build" it. When I make a wheel I "package" it.
I believe that modern packaging calls the whole thing "build"? Or just the latter step?
Incidentally, "python -m build --sdist" on my project does not work as a replacement for "python setup.py sdist" because my setup.py includes a code generation step to get from a clean repo to the Python/C extension files included in the distribution. I haven't figured out the modern way to handle that. I think it's because of the differences in philosophy of what "build" means, and what actions are allowed during different stages of the distribution process, which is why I think "build" needs a specific definition, just like "project" and "release" have specific definitions.
I mean, my actual prior here is that nobody should care or even think about this stuff. Authenticity and minimally-scoped credentials should be ambient properties of a system, not something that users even need to read docs for, much less enable. But if we're engaging with the premise that users are looking at this stuff at all, then I think it's facially reasonable to expect them to read the docs.
For context: attestations aren't something you even really enable. They just happen, by default, if you use Trusted Publishing from a forge like GitHub or GitLab (and hopefully, more in the future).
FWIW, your feedback on the docs is very helpful. It's genuinely useful to hear that the phrasing in it is imprecise, and I'll try and improve some of it this week. The main confusion that I think you're having (which is IMO reasonable) is that the doc was written to be theoretically splittable from the "Trusted Publishing" concept, i.e. so that "publishers" (principals who can publish) who aren't tied to a Trusted Publisher can attest to their published files.
> nobody should care or even think about this stuff.
Does that mean I, as someone who has projects on PyPI, shouldn't care if I am unable to provide any attestations because I don't want to have to go through one of the recognized forges?
> Authenticity and minimally-scoped credentials should be ambient properties of a system
But if the only way to get them is to go through one of the recognized forges, then they're not "ambient properties" of just PyPI alone, because there's no way for me to use them just with PyPI alone.
Okay, but if the information is on the project page then it's pretty likely that users will look at this stuff without reading the docs. My feeling was the doc was written for people "Publishing Projects to PyPI" and not for people "Using PyPI", quoting the relevant sections of the documentation.
Of course, in real life 99.9% of people aren't looking at the page at all, and either following a documentation step which says "install by doing XYZ" or transitively from some other project they install.
I'll compare "attestations aren't something you even really enable" with this from the email attestation proposal: "Another possibility here would be to have it be opt-in: maintainers can mark their already-verified emails as being eligible for attestations on PyPI, e.g. via a checkbox in the user settings." ;)
I also can't help but wonder who reads https://docs.pypi.org/publishing/publishing-to-pypi/ where it says "For instructions on how to package your Python project, please refer to the Python Packaging User Guide.", follows those steps including the one about using twine and TestPyPI, does all that, and then gets to "Publishing package distribution releases using GitHub Actions CI/CD workflows" and gives up, since twine works.
Or goes back to the pypi documentation and sees "To use an API token: Set your username to __token__" when I can't find anything like that at https://packaging.python.org/en/latest/guides/publishing-pac... , Those seem like describing two very different systems, speaking as someone with no experience with them at all, who learned to use twine because of the Python Packaging User Guide.