Source Code for Module Anomos.Crypto._PeerCert

 1  # This program is free software: you can redistribute it and/or modify 
 2  # it under the terms of the GNU General Public License as published by 
 3  # the Free Software Foundation, either version 3 of the License, or 
 4  # (at your option) any later version. 
 5  # 
 6  # This program is distributed in the hope that it will be useful, 
 7  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 8  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 9  # GNU General Public License for more details. 
10  # 
11  # You should have received a copy of the GNU General Public License 
12  # along with this program.  If not, see <http://www.gnu.org/licenses/>. 
13   
14  import hashlib 
15   
16  from M2Crypto import RSA, X509 
17   
18  from Anomos import tobinary 
19  from Anomos.Crypto import global_randfile 
20  import Anomos.Crypto 
21   
22 -class PeerCert: 
23 -    def __init__(self, certObj): 
24          self.hash_alg = 'sha256' 
25          self.fingerprint = certObj.get_fingerprint(self.hash_alg) 
26          self.pubkey = certObj.get_pubkey().get_rsa() 
27          # The following prevents a nasty segfault in M2Crypto 
28          # versions < .19 
29          # TODO: Ban M2Cryto versions < 0.19 and remove this 
30          if not isinstance(self.pubkey, RSA.RSA_pub): 
31              self.pubkey = RSA.new_pub_key((self.pubkey.e, self.pubkey.n)) 
32   
33 -    def cmp(self, certObj): 
34          return self.fingerprint == certObj.get_fingerprint(self.hash_alg) 
35   
36 -    def encrypt(self, data, rmsglen=None): 
37          """ 
38          @type data: string 
39          @return: ciphertext of data, format: {RSA encrypted session key}[Checksum(sessionkey, info, content)][msg length][content][padding] 
40          @rtype: string 
41          """ 
42          sessionkey = Anomos.Crypto.AESKey() 
43          # Encrypt the session key which we'll use to bulk encrypt the rest of the data 
44          esk = self.pubkey.public_encrypt(sessionkey.key+sessionkey.iv, RSA.pkcs1_oaep_padding) 
45          if rmsglen: 
46              bmsglen = tobinary(rmsglen) 
47          else: 
48              rmsglen = len(data) 
49              bmsglen = tobinary(len(data)) 
50          checksum = hashlib.sha1(sessionkey.key + bmsglen + data[:rmsglen]).digest() 
51          content = checksum + bmsglen + data 
52          padlen = 32-(len(content)%32) 
53          padding = Anomos.Crypto.get_rand(padlen) 
54          ciphertext = sessionkey.encrypt(content+padding) 
55          return esk + ciphertext 
56