SOSS Fusion 2024

PyPI is the official package index for the Python programming language, and one of the largest OSS package indices, serving over 1.2 billion downloads of over 500,000 unique packages each day to millions of Python developers and hundreds of millions of downstream users. As the cornerstone of a massive and diverse language ecosystem, changes to PyPI's security posture (and security features offered) represent a significant operational challenge, one shared by indices of similar size and criticality (such as NPM, RubyGems, and Crates). This talk is about one such change in PyPI's security posture: the creation and (ongoing) implementation of PEP 740, or "Index support for digital attestations." This talk will go through the details of PEP 740, how it relates to (and integrates with) standards like Sigstore, in-toto, and SLSA, and how PyPI (and Python packaging more broadly) is using PEP 740 to "bootstrap" strong, maintainer digital provenance for Python packages on top of PyPI's pre-existing support for Trusted Publishing, without the traditional downsides of key and identity management, complex signing ceremonies, and so forth.