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# License?
"""A U1DB implementation for using Object Stores as its persistence layer."""
import os
import string
import random
import cStringIO
import hmac
from backends import sqlcipher
from soledad.util import GPGWrapper
class Soledad(object):
# paths
PREFIX = os.environ['HOME'] + '/.config/leap/soledad'
SECRET_PATH = PREFIX + '/secret.gpg'
GNUPG_HOME = PREFIX + '/gnupg'
U1DB_PATH = PREFIX + '/soledad.u1db'
# other configs
SECRET_LENGTH = 50
def __init__(self, user_email, gpghome=None):
self._user_email = user_email
if not os.path.isdir(self.PREFIX):
os.makedirs(self.PREFIX)
if not gpghome:
gpghome = self.GNUPG_HOME
self._gpg = GPGWrapper(gpghome=gpghome)
# load OpenPGP keypair
if not self._has_openpgp_keypair():
self._gen_openpgp_keypair()
self._load_openpgp_keypair()
# load secret
if not self._has_secret():
self._gen_secret()
self._load_secret()
# instantiate u1db
# TODO: verify if secret for sqlcipher should be the same as the one
# for symmetric encryption.
self._db = sqlcipher.open(self.U1DB_PATH, True, self._secret)
#-------------------------------------------------------------------------
# Symmetric secret management
#-------------------------------------------------------------------------
def _has_secret(self):
"""
Verify if secret for symmetric encryption exists on local encrypted file.
"""
# TODO: verify if file is a GPG-encrypted file and if we have the
# corresponding private key for decryption.
if os.path.isfile(self.SECRET_PATH):
return True
return False
def _load_secret(self):
"""
Load secret for symmetric encryption from local encrypted file.
"""
try:
with open(self.SECRET_PATH) as f:
self._secret = str(self._gpg.decrypt(f.read()))
except IOError as e:
raise IOError('Failed to open secret file %s.' % self.SECRET_PATH)
def _gen_secret(self):
"""
Generate a secret for symmetric encryption and store in a local encrypted file.
"""
self._secret = ''.join(random.choice(string.ascii_uppercase + string.digits) for x in range(self.SECRET_LENGTH))
ciphertext = self._gpg.encrypt(self._secret, self._fingerprint, self._fingerprint)
f = open(self.SECRET_PATH, 'w')
f.write(str(ciphertext))
f.close()
#-------------------------------------------------------------------------
# OpenPGP keypair management
#-------------------------------------------------------------------------
def _has_openpgp_keypair(self):
"""
Verify if there exists an OpenPGP keypair for this user.
"""
# TODO: verify if we have the corresponding private key.
try:
self._gpg.find_key(self._user_email)
return True
except LookupError:
return False
def _gen_openpgp_keypair(self):
"""
Generate and OpenPGP keypair for this user.
"""
params = self._gpg.gen_key_input(
key_type='RSA',
key_length=4096,
name_real=self._user_email,
name_email=self._user_email,
name_comment='Generated by LEAP Soledad.')
self._gpg.gen_key(params)
def _load_openpgp_keypair(self):
"""
Find fingerprint for this user's OpenPGP keypair.
"""
self._fingerprint = self._gpg.find_key(self._user_email)['fingerprint']
def publish_pubkey(self, keyserver):
pass
#-------------------------------------------------------------------------
# Data encryption/decryption
#-------------------------------------------------------------------------
def encrypt(self, data, sign=None, passphrase=None, symmetric=False):
"""
Encrypt data.
"""
return str(self._gpg.encrypt(data, self._fingerprint, sign=sign,
passphrase=passphrase, symmetric=symmetric))
def encrypt_symmetric(self, doc_id, data, sign=None):
"""
Encrypt data using symmetric secret.
"""
h = hmac.new(self._secret, doc_id).hexdigest()
return self.encrypt(data, sign=sign, passphrase=h, symmetric=True)
def decrypt(self, data, passphrase=None, symmetric=False):
"""
Decrypt data.
"""
return str(self._gpg.decrypt(data, passphrase=passphrase))
def decrypt_symmetric(self, doc_id, data):
"""
Decrypt data using symmetric secret.
"""
h = hmac.new(self._secret, doc_id).hexdigest()
return self.decrypt(data, passphrase=h)
#-------------------------------------------------------------------------
# Document storage/retrieval and sync
#-------------------------------------------------------------------------
def put(self, doc_id, data):
"""
Store a document in the local encrypted database.
"""
pass
def get(self, doc_id):
"""
Retrieve a document from the local encrypted database.
"""
pass
def sync(self):
"""
Synchronize the local encrypted database with LEAP server.
"""
pass
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