You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.
hashdecrypt was reported malicious
OSV:MAL-2024-5197 - Malicious code in hashdecrypt (PyPI)

hashdecrypt
1.0.0

This version was deleted from PyPI around 2024-02-23. Installing fails with:
$ pip3 install hashdecrypt==1.0.0 ERROR: Could not find a version that satisfies the requirement hashdecrypt==1.0.0
View other deleted versions of hashdecrypt

Install through StableBuild

You can install this package from StableBuild's PyPI snapshots from before the version was deleted:
pip3 install \ -i https://YOUR_API_KEY.pypimirror.stablebuild.com/2024-02-21/ \ hashdecrypt==1.0.0
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Or, download files manually

And install manually via pip:
hashdecrypt-1.0.0-py3-none-any.whl (1.9KB)
hashdecrypt-1.0.0.tar.gz (1.7KB)