sign: Implement attestation signing #94
Description
What would you like to be added:
Our signing library should implement signing of in-toto attestations
Why is this needed:
We need to build our own attestation signing code for three main reasons:
- Signing our provenance attestations during the release process
- Being able to attest of image promoter runs via a signed attestation
- Making sure we can produce general purpose code and tools that other projects in the kubernetes org (and elsewhere) can leverage to generate attestation and build attesting features into other projects.
/kind feature