In its current implementation, a user is required to provide their cleartext PyPi password in their .pypirc configuration file for authenticated interactions with PyPi servers to succeed. For hopefully obvious reasons, this is sub-optimal from a security standpoint.

In some popular utilities (e.g. msmtp), the ability to provide a `passwordeval` field is made optional to the user. The value to this field is executed by the OS-dependent shell, and the return value is then used as the password.

For example, instead of this:

```
index-servers=
    pypi

[pypi]
username=jperras
password=mygreatpassword

```

we can instead have this:

```
index-servers=
    pypi

[pypi]
username=jperras
passwordeval="gpg --quiet --for-your-eyes-only --no-tty --decrypt ~/.pypipwd.gpg"
```