The issue is kinda more complex: cryptography is also a hard dependency of pip, the official Python package installer. And CPython itself seem to support PPC64 and s390x — which are Tier 2 targets for rust.

Hence, pip now depends on software that is not tested on some platforms officially supported by Python…

Sources: - https://doc.rust-lang.org/nightly/rustc/platform-support.htm... - https://buildbot.python.org/all/#/grid