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Diffstat (limited to 'src/leap/common/keymanager/keys.py')
| -rw-r--r-- | src/leap/common/keymanager/keys.py | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/src/leap/common/keymanager/keys.py b/src/leap/common/keymanager/keys.py new file mode 100644 index 0000000..2e6bfe9 --- /dev/null +++ b/src/leap/common/keymanager/keys.py @@ -0,0 +1,230 @@ +# -*- coding: utf-8 -*- +# keys.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/>. + + +""" +Abstact key type and encryption scheme representations. +""" + + +try: + import simplejson as json +except ImportError: + import json # noqa +import re + + +from hashlib import sha256 +from abc import ABCMeta, abstractmethod +from leap.common.check import leap_assert + + +# +# Key handling utilities +# + +def is_address(address): + """ + Return whether the given C{address} is in the form user@provider. + + @param address: The address to be tested. + @type address: str + @return: Whether C{address} is in the form user@provider. + @rtype: bool + """ + return bool(re.match('[\w.-]+@[\w.-]+', address)) + + +def build_key_from_dict(kClass, address, kdict): + """ + Build an C{kClass} key bound to C{address} based on info in C{kdict}. + + @param address: The address bound to the key. + @type address: str + @param kdict: Dictionary with key data. + @type kdict: dict + @return: An instance of the key. + @rtype: C{kClass} + """ + leap_assert(address == kdict['address'], 'Wrong address in key data.') + return kClass( + address, + key_id=kdict['key_id'], + fingerprint=kdict['fingerprint'], + key_data=kdict['key_data'], + private=kdict['private'], + length=kdict['length'], + expiry_date=kdict['expiry_date'], + first_seen_at=kdict['first_seen_at'], + last_audited_at=kdict['last_audited_at'], + validation=kdict['validation'], # TODO: verify for validation. + ) + + +def keymanager_doc_id(ktype, address, private=False): + """ + Return the document id for the document containing a key for + C{address}. + + @param address: The type of the key. + @type address: KeyType + @param address: The address bound to the key. + @type address: str + @param private: Whether the key is private or not. + @type private: bool + @return: The document id for the document that stores a key bound to + C{address}. + @rtype: str + """ + leap_assert(is_address(address), "Wrong address format: %s" % address) + ktype = str(ktype) + visibility = 'private' if private else 'public' + return sha256('keymanager-'+address+'-'+ktype+'-'+visibility).hexdigest() + + +# +# Abstraction for encryption keys +# + +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, private=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.private = private + 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 + + def get_json(self): + """ + Return a JSON string describing this key. + + @return: The JSON string describing this key. + @rtype: str + """ + return json.dumps({ + 'address': self.address, + 'type': str(self.__class__), + 'key_id': self.key_id, + 'fingerprint': self.fingerprint, + 'key_data': self.key_data, + 'private': self.private, + 'length': self.length, + 'expiry_date': self.expiry_date, + 'validation': self.validation, + 'first_seen_at': self.first_seen_at, + 'last_audited_at': self.last_audited_at, + 'tags': ['keymanager-key'], + }) + + +# +# Encryption schemes +# + +class EncryptionScheme(object): + """ + Abstract class for Encryption Schemes. + + A wrapper for a certain encryption schemes should know how to get and put + keys in local storage using Soledad, how to generate new keys and how to + find out about possibly encrypted content. + """ + + __metaclass__ = ABCMeta + + def __init__(self, soledad): + """ + Initialize this Encryption Scheme. + + @param soledad: A Soledad instance for local storage of keys. + @type soledad: leap.soledad.Soledad + """ + self._soledad = soledad + + @abstractmethod + def get_key(self, address, private=False): + """ + Get key from local storage. + + @param address: The address bound to the key. + @type address: str + @param private: Look for a private key instead of a public one? + @type private: bool + + @return: The key bound to C{address}. + @rtype: EncryptionKey + @raise KeyNotFound: If the key was not found on local storage. + """ + pass + + @abstractmethod + def put_key(self, key): + """ + Put a key in local storage. + + @param key: The key to be stored. + @type key: EncryptionKey + """ + pass + + @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 + """ + pass + + @abstractmethod + def delete_key(self, key): + """ + Remove C{key} from storage. + + @param key: The key to be removed. + @type key: EncryptionKey + """ + pass |