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# -*- coding: utf-8 -*-
# __init__.py
# Copyright (C) 2014 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Validation levels implementation for key managment.
See:
https://lists.riseup.net/www/arc/leap-discuss/2014-09/msg00000.html
"""
from datetime import datetime
from enum import Enum
ValidationLevel = Enum(
"Weak_Chain",
"Provider_Trust",
"Provider_Endorsement",
"Third_Party_Endorsement",
"Third_Party_Consensus",
"Historically_Auditing",
"Known_Key",
"Fingerprint")
def toValidationLevel(value):
"""
Convert a string representation of a validation level into
C{ValidationLevel}
:param value: validation level
:type value: str
:rtype: ValidationLevel
:raises ValueError: if C{value} is not a validation level
"""
for level in ValidationLevel:
if value == str(level):
return level
raise ValueError("Not valid validation level: %s" % (value,))
def can_upgrade(new_key, old_key):
"""
:type new_key: EncryptionKey
:type old_key: EncryptionKey
:rtype: bool
"""
# XXX not succesfully used and strict high validation level (#6211)
# XXX implement key signature checking (#6120)
# First contact
if old_key is None:
return True
if new_key.address != old_key.address:
# XXX how do we map multiple IDs? (#6212)
return False
# An update of the same key
if new_key.fingerprint == old_key.fingerprint:
# XXX wich one is newer? is that a downgrade attack? (#6210)
return True
# Manually verified fingerprint
if new_key.validation == ValidationLevel.Fingerprint:
return True
# Expired key and higher validation level
if old_key.expiry_date:
old_expiry_date = datetime.fromtimestamp(int(old_key.expiry_date))
if (old_expiry_date < datetime.now() and
new_key.validation >= old_key.validation):
return True
# No expiration date and higher validation level
elif new_key.validation >= old_key.validation:
return True
return False
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