zulip/zerver/lib/initial_password.py

from __future__ import absolute_import

from django.conf import settings

import hashlib
import base64

from typing import Optional
from six import text_type


def initial_password(email):
    # type: (text_type) -> Optional[text_type]
    """Given an email address, returns the initial password for that account, as
       created by populate_db."""

    if settings.INITIAL_PASSWORD_SALT is not None:
        encoded_key = (settings.INITIAL_PASSWORD_SALT + email).encode("utf-8")
        digest = hashlib.sha256(encoded_key).digest()
        return base64.b64encode(digest)[:16]
    else:
        # None as a password for a user tells Django to set an unusable password
        return None