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# -*- coding: utf-8 -*-
# __init__.py
# Copyright (C) 2013 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/>.
"""
Key Manager is a Nicknym agent for LEAP client.
"""
try:
import simplejson as json
except ImportError:
import json # noqa
from abc import ABCMeta, abstractmethod
from u1db.errors import HTTPError
#
# Key types
#
class EncryptionKey(object):
"""
Abstract class for encryption keys.
A key is "validated" if the nicknym agent has bound the user address to a
public key. Nicknym supports three different levels of key validation:
* Level 3 - path trusted: A path of cryptographic signatures can be traced
from a trusted key to the key under evaluation. By default, only the
provider key from the user's provider is a "trusted key".
* level 2 - provider signed: The key has been signed by a provider key for
the same domain, but the provider key is not validated using a trust
path (i.e. it is only registered)
* level 1 - registered: The key has been encountered and saved, it has no
signatures (that are meaningful to the nicknym agent).
"""
__metaclass__ = ABCMeta
def __init__(self, address, key_id=None, fingerprint=None,
key_data=None, length=None, expiry_date=None,
validation=None, first_seen_at=None,
last_audited_at=None):
self.address = address
self.key_id = key_id
self.fingerprint = fingerprint
self.key_data = key_data
self.length = length
self.expiry_date = expiry_date
self.validation = validation
self.first_seen_at = first_seen_at
self.last_audited_at = last_audited_at
@abstractmethod
def get_json(self):
"""
Return a JSON string describing this key.
@return: The JSON string describing this key.
@rtype: str
"""
#
# Key wrappers
#
class KeyTypeWrapper(object):
"""
Abstract class for Key Type Wrappers.
A wrapper for a certain key type should know how to get and put keys in
local storage using Soledad and also how to generate new keys.
"""
__metaclass__ = ABCMeta
@abstractmethod
def get_key(self, address):
"""
Get key from local storage.
@param address: The address bound to the key.
@type address: str
@return: The key bound to C{address}.
@rtype: EncryptionKey
@raise KeyNotFound: If the key was not found on local storage.
"""
@abstractmethod
def put_key(self, key):
"""
Put a key in local storage.
@param key: The key to be stored.
@type key: EncryptionKey
"""
@abstractmethod
def gen_key(self, address):
"""
Generate a new key.
@param address: The address bound to the key.
@type address: str
@return: The key bound to C{address}.
@rtype: EncryptionKey
"""
#
# Key manager
#
class KeyNotFound(Exception):
"""
Raised when key was no found on keyserver.
"""
class KeyManager(object):
def __init__(self, address, url):
"""
Initialize a Key Manager for user's C{address} with provider's
nickserver reachable in C{url}.
@param address: The address of the user of this Key Manager.
@type address: str
@param url: The URL of the key manager.
@type url: str
"""
self.address = address
self.url = url
def send_key(self, ktype, send_private=False, password=None):
"""
Send user's key of type C{ktype} to provider.
Public key bound to user's is sent to provider, which will sign it and
replace any prior keys for the same address in its database.
If C{send_private} is True, then the private key is encrypted with
C{password} and sent to server in the same request, together with a
hash string of user's address and password. The encrypted private key
will be saved in the server in a way it is publicly retrievable
through the hash string.
@param address: The address bound to the key.
@type address: str
@param ktype: The type of the key.
@type ktype: KeyType
@raise httplib.HTTPException:
"""
def get_key(self, address, ktype):
"""
Return a key of type C{ktype} bound to C{address}.
First, search for the key in local storage. If it is not available,
then try to fetch from nickserver.
@param address: The address bound to the key.
@type address: str
@param ktype: The type of the key.
@type ktype: KeyType
@return: A key of type C{ktype} bound to C{address}.
@rtype: EncryptionKey
@raise KeyNotFound: If the key was not found both locally and in
keyserver.
"""
try:
return wrapper_map[ktype].get_key(address)
except KeyNotFound:
key = filter(lambda k: isinstance(k, ktype),
self._fetch_keys(address))
if key is None
raise KeyNotFound()
wrapper_map[ktype].put_key(key)
return key
def _fetch_keys(self, address):
"""
Fetch keys bound to C{address} from nickserver.
@param address: The address bound to the keys.
@type address: str
@return: A list of keys bound to C{address}.
@rtype: list of EncryptionKey
@raise KeyNotFound: If the key was not found on nickserver.
@raise httplib.HTTPException:
"""
def refresh_keys(self):
"""
Update the user's db of validated keys to see if there are changes.
"""
def gen_key(self, ktype):
"""
Generate a key of type C{ktype} bound to the user's address.
@param ktype: The type of the key.
@type ktype: KeyType
@return: The generated key.
@rtype: EncryptionKey
"""
return wrapper_map[ktype].gen_key(self.address)
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