> Where does the user specify the cryptographic key to sign a package before uploading?
With Sigstore, they perform an OIDC flow against an identity provider: that results in a verifiable identity credential, which is then bound to a short-lived (~15m) signing key that produces the signatures. That signing key is simultaneously attested through a traditional X.509 PKI (it gets a certificate, that certificate is uploaded to an append-only transparency log, etc.).
So: in the normal flow, the user never directly specifies the cryptographic key -- the scheme ensures that they have a strong, ephemeral one generated for them on the spot (and only on their client device, in RAM). That key gets bound to their long-lived identity, so verifiers don't need to know which key they're verifying; they only need to determine whether they trust the identity itself (which can be an email address, a GitHub repository, etc.).
What command(s) do I pass to pip/twine/build_pyproject.toml to build, upload, and install a package with a key/cert that users should trust for e.g. psf/requests?
With Sigstore, they perform an OIDC flow against an identity provider: that results in a verifiable identity credential, which is then bound to a short-lived (~15m) signing key that produces the signatures. That signing key is simultaneously attested through a traditional X.509 PKI (it gets a certificate, that certificate is uploaded to an append-only transparency log, etc.).
So: in the normal flow, the user never directly specifies the cryptographic key -- the scheme ensures that they have a strong, ephemeral one generated for them on the spot (and only on their client device, in RAM). That key gets bound to their long-lived identity, so verifiers don't need to know which key they're verifying; they only need to determine whether they trust the identity itself (which can be an email address, a GitHub repository, etc.).