1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
# -*- coding: utf-8 -*-
# crypto.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/>.
"""
Cryptographic utilities for Soledad.
"""
from binascii import b2a_base64
from hashlib import sha256
from leap.common.keymanager import openpgp
class NoSymmetricSecret(Exception):
"""
Raised when trying to get a hashed passphrase.
"""
class SoledadCrypto(object):
"""
General cryptographic functionality.
"""
def __init__(self, soledad):
"""
Initialize the crypto object.
@param soledad: A Soledad instance for key lookup.
@type soledad: leap.soledad.Soledad
"""
self._soledad = soledad
self._pgp = openpgp.OpenPGPScheme(self._soledad)
self._symkey = None
def encrypt_asym(self, data, key):
"""
Encrypt data.
@param data: the data to be encrypted
@type data: str
@param key: the key to be used for encryption
@type key: str
@return: the encrypted data
@rtype: str
"""
return openpgp.encrypt_asym(data, key)
def encrypt_sym(self, data, passphrase):
"""
Encrypt C{data} using a {password}.
@param data: the data to be encrypted
@type data: str
@param passphrase: the passphrase to use for encryption
@type passphrase: str
@return: the encrypted data
@rtype: str
"""
return openpgp.encrypt_sym(data, passphrase)
def decrypt_asym(self, data):
"""
Decrypt data.
@param data: the data to be decrypted
@type data: str
@param passphrase: the passphrase to be used for decryption
@type passphrase: str
@return: the decrypted data
@rtype: str
"""
key = self._pgp.get_key(self._soledad.address, private=True)
return openpgp.decrypt_asym(data, key)
def decrypt_sym(self, data, passphrase):
"""
Decrypt data using symmetric secret.
@param data: the data to be decrypted
@type data: str
@param passphrase: the passphrase to use for decryption
@type passphrase: str
@return: the decrypted data
@rtype: str
"""
return openpgp.decrypt_sym(data, passphrase)
def is_encrypted(self, data):
"""
Test whether some chunk of data is a cyphertext.
@param data: the data to be tested
@type data: str
@return: whether the data is a cyphertext
@rtype: bool
"""
return openpgp.is_encrypted(data)
def is_encrypted_sym(self, data):
"""
Test whether some chunk of data was encrypted with a symmetric key.
@return: whether data is encrypted to a symmetric key
@rtype: bool
"""
return openpgp.is_encrypted_sym(data)
def is_encrypted_asym(self, data):
"""
Test whether some chunk of data was encrypted to an OpenPGP private
key.
@return: whether data is encrypted to an OpenPGP private key
@rtype: bool
"""
return openpgp.is_encrypted_asym(data)
def passphrase_hash(self, suffix):
"""
Generate a passphrase for symmetric encryption.
The password is derived from the secret for symmetric encryption and
a C{suffix} that is appended to the secret prior to hashing.
@param suffix: Will be appended to the symmetric key before hashing.
@type suffix: str
@return: the passphrase
@rtype: str
@raise NoSymmetricSecret: if no symmetric secret was supplied.
"""
if self._symkey is None:
raise NoSymmetricSecret()
return b2a_base64(
sha256('%s%s' % (self._symkey, suffix)).digest())[:-1]
#
# symkey setters/getters
#
def _get_symkey(self):
return self._symkey
def _set_symkey(self, symkey):
self._symkey = symkey
symkey = property(_get_symkey, _set_symkey,
doc='The key used for symmetric encryption')
|
