[refactor] improve secrets generation and storage code

8 files changed, 440 insertions, 911 deletions

diff --git a/client/src/leap/soledad/client/_secrets/__init__.py b/client/src/leap/soledad/client/_secrets/__init__.py
new file mode 100644
index 00000000..f9da8423
--- /dev/null
+++ b/client/src/leap/soledad/client/_secrets/__init__.py
@@ -0,0 +1,132 @@
+# -*- coding: utf-8 -*-
+# _secrets/__init__.py
+# Copyright (C) 2016 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/>.
+
+import os
+
+from collections import namedtuple
+
+from leap.soledad.common.log import getLogger
+
+from leap.soledad.client._secrets.storage import SecretsStorage
+from leap.soledad.client._secrets.crypto import SecretsCrypto
+from leap.soledad.client._secrets.util import emit
+
+
+logger = getLogger(__name__)
+
+
+SecretLength = namedtuple('SecretLength', 'name length')
+
+
+class Secrets(object):
+
+    lengths = {
+        'remote': 512,
+        'salt': 64,
+        'local': 448,
+    }
+
+    def __init__(self, uuid, passphrase, url, local_path, creds, userid,
+                 shared_db=None):
+        self._passphrase = passphrase
+        self._secrets = {}
+        self._user_data = {'uuid': uuid, 'userid': userid}
+        self.crypto = SecretsCrypto(self.get_passphrase)
+        self.storage = SecretsStorage(
+            uuid, self.get_passphrase, url, local_path, creds, userid,
+            shared_db=shared_db)
+        self._bootstrap()
+
+    #
+    # bootstrap
+    #
+
+    def _bootstrap(self):
+        force_storage = False
+
+        # attempt to load secrets from local storage
+        encrypted = self.storage.load_local()
+
+        # if not found, attempt to load secrets from remote storage
+        if not encrypted:
+            encrypted = self.storage.load_remote()
+
+        if not encrypted:
+            # if not found, generate new secrets
+            secrets = self._generate()
+            encrypted = self.crypto.encrypt(secrets)
+            force_storage = True
+        else:
+            # decrypt secrets found either in local or remote storage
+            secrets = self.crypto.decrypt(encrypted)
+
+        self._secrets = secrets
+
+        if encrypted['version'] < self.crypto.VERSION or force_storage:
+            self.storage.save_local(encrypted)
+            self.storage.save_remote(encrypted)
+
+    #
+    # generation
+    #
+
+    @emit('creating')
+    def _generate(self):
+        logger.info("generating new set of secrets...")
+        secrets = {}
+        for name, length in self.lengths.iteritems():
+            secret = os.urandom(length)
+            secrets[name] = secret
+        logger.info("new set of secrets successfully generated")
+        return secrets
+
+    #
+    # crypto
+    #
+
+    def _encrypt(self):
+        # encrypt secrets
+        secrets = self._secrets
+        encrypted = self.crypto.encrypt(secrets)
+        # create the recovery document
+        data = {'secret': encrypted, 'version': 2}
+        return data
+
+    def get_passphrase(self):
+        return self._passphrase.encode('utf-8')
+
+    @property
+    def passphrase(self):
+        return self.get_passphrase()
+
+    def change_passphrase(self, new_passphrase):
+        self._passphrase = new_passphrase
+        encrypted = self.crypto.encrypt(self._secrets)
+        self.storage.save_local(encrypted)
+        self.storage.save_remote(encrypted)
+
+    @property
+    def remote(self):
+        return self._secrets.get('remote')
+
+    @property
+    def salt(self):
+        return self._secrets.get('salt')
+
+    @property
+    def local(self):
+        return self._secrets.get('local')
diff --git a/client/src/leap/soledad/client/_secrets/crypto.py b/client/src/leap/soledad/client/_secrets/crypto.py
new file mode 100644
index 00000000..76e80222
--- /dev/null
+++ b/client/src/leap/soledad/client/_secrets/crypto.py
@@ -0,0 +1,123 @@
+# -*- coding: utf-8 -*-
+# _secrets/crypto.py
+# Copyright (C) 2016 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/>.
+
+import binascii
+import json
+import os
+import scrypt
+
+from leap.soledad.common import soledad_assert
+from leap.soledad.common.log import getLogger
+
+from leap.soledad.client._crypto import encrypt_sym, decrypt_sym, ENC_METHOD
+from leap.soledad.client._secrets.util import SecretsError
+
+
+logger = getLogger(__name__)
+
+
+class SecretsCrypto(object):
+
+    VERSION = 2
+
+    def __init__(self, get_pass):
+        self._get_pass = get_pass
+
+    def _get_key(self, salt):
+        key = scrypt.hash(self._get_pass(), salt, buflen=32)
+        return key
+
+    #
+    # encryption
+    #
+
+    def encrypt(self, secrets):
+        encoded = {}
+        for name, value in secrets.iteritems():
+            encoded[name] = binascii.b2a_base64(value)
+        plaintext = json.dumps(encoded)
+        salt = os.urandom(64)  # TODO: get salt length from somewhere else
+        key = self._get_key(salt)
+        iv, ciphertext = encrypt_sym(plaintext, key,
+                                     method=ENC_METHOD.aes_256_gcm)
+        encrypted = {
+            'version': self.VERSION,
+            'kdf': 'scrypt',
+            'kdf_salt': binascii.b2a_base64(salt),
+            'kdf_length': len(key),
+            'cipher': 'aes_256_gcm',
+            'length': len(plaintext),
+            'iv': str(iv),
+            'secrets': binascii.b2a_base64(ciphertext),
+        }
+        return encrypted
+
+    #
+    # decryption
+    #
+
+    def decrypt(self, data):
+        version = data.get('version')
+        method = getattr(self, '_decrypt_v%d' % version)
+        try:
+            return method(data)
+        except Exception as e:
+            logger.error('error decrypting secrets: %r' % e)
+            raise SecretsError(e)
+
+    def _decrypt_v1(self, data):
+        secret_id = data['active_secret']
+        encrypted = data['storage_secrets'][secret_id]
+        soledad_assert(encrypted['cipher'] == 'aes256')
+
+        salt = binascii.a2b_base64(encrypted['kdf_salt'])
+        key = self._get_key(salt)
+        separator = ':'
+        iv, ciphertext = encrypted['secret'].split(separator, 1)
+        ciphertext = binascii.a2b_base64(ciphertext)
+        plaintext = self._decrypt(
+            key, iv, ciphertext, encrypted, ENC_METHOD.aes_256_ctr)
+        secrets = {
+            'remote': plaintext[0:512],
+            'salt': plaintext[512:576],
+            'local': plaintext[576:1024],
+        }
+        return secrets
+
+    def _decrypt_v2(self, encrypted):
+        soledad_assert(encrypted['cipher'] == 'aes_256_gcm')
+
+        salt = binascii.a2b_base64(encrypted['kdf_salt'])
+        key = self._get_key(salt)
+        iv = encrypted['iv']
+        ciphertext = binascii.a2b_base64(encrypted['secrets'])
+        plaintext = self._decrypt(
+            key, iv, ciphertext, encrypted, ENC_METHOD.aes_256_gcm)
+        encoded = json.loads(plaintext)
+        secrets = {}
+        for name, value in encoded.iteritems():
+            secrets[name] = binascii.a2b_base64(value)
+        return secrets
+
+    def _decrypt(self, key, iv, ciphertext, encrypted, method):
+        # assert some properties of the stored secret
+        soledad_assert(encrypted['kdf'] == 'scrypt')
+        soledad_assert(encrypted['kdf_length'] == len(key))
+        # decrypt
+        plaintext = decrypt_sym(ciphertext, key, iv, method)
+        soledad_assert(encrypted['length'] == len(plaintext))
+        return plaintext
diff --git a/client/src/leap/soledad/client/_secrets/storage.py b/client/src/leap/soledad/client/_secrets/storage.py
new file mode 100644
index 00000000..da3aa9d7
--- /dev/null
+++ b/client/src/leap/soledad/client/_secrets/storage.py
@@ -0,0 +1,124 @@
+# -*- coding: utf-8 -*-
+# _secrets/storage.py
+# Copyright (C) 2016 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/>.
+
+import json
+import urlparse
+
+from hashlib import sha256
+
+from leap.soledad.common import SHARED_DB_NAME
+from leap.soledad.common.log import getLogger
+
+from leap.soledad.common.document import SoledadDocument
+from leap.soledad.client.shared_db import SoledadSharedDatabase
+from leap.soledad.client._secrets.util import emit
+
+
+logger = getLogger(__name__)
+
+
+class SecretsStorage(object):
+
+    def __init__(self, uuid, get_pass, url, local_path, creds, userid,
+                 shared_db=None):
+        self._uuid = uuid
+        self._get_pass = get_pass
+        self._local_path = local_path
+        self._userid = userid
+
+        self._shared_db = shared_db or self._init_shared_db(url, creds)
+        self.__remote_doc = None
+
+    #
+    # properties
+    #
+
+    @property
+    def _user_data(self):
+        return {'uuid': self._uuid, 'userid': self._userid}
+
+    #
+    # local storage
+    #
+
+    def load_local(self):
+        logger.info("trying to load secrets from disk: %s" % self._local_path)
+        try:
+            with open(self._local_path, 'r') as f:
+                encrypted = json.loads(f.read())
+            logger.info("secrets loaded successfully from disk")
+            return encrypted
+        except IOError:
+            logger.warn("secrets not found in disk")
+        return None
+
+    def save_local(self, encrypted):
+        json_data = json.dumps(encrypted)
+        with open(self._local_path, 'w') as f:
+            f.write(json_data)
+
+    #
+    # remote storage
+    #
+
+    def _init_shared_db(self, url, creds):
+        url = urlparse.urljoin(url, SHARED_DB_NAME)
+        db = SoledadSharedDatabase.open_database(
+            url, self._uuid, creds=creds)
+        self._shared_db = db
+
+    def _remote_doc_id(self):
+        passphrase = self._get_pass()
+        text = '%s%s' % (passphrase, self._uuid)
+        digest = sha256(text).hexdigest()
+        return digest
+
+    @property
+    def _remote_doc(self):
+        if not self.__remote_doc and self._shared_db:
+            doc = self._get_remote_doc()
+            self.__remote_doc = doc
+        return self.__remote_doc
+
+    @emit('downloading')
+    def _get_remote_doc(self):
+        logger.info('trying to load secrets from server...')
+        doc = self._shared_db.get_doc(self._remote_doc_id())
+        if doc:
+            logger.info('secrets loaded successfully from server')
+        else:
+            logger.warn('secrets not found in server')
+        return doc
+
+    def load_remote(self):
+        doc = self._remote_doc
+        if not doc:
+            return None
+        encrypted = doc.content
+        return encrypted
+
+    @emit('uploading')
+    def save_remote(self, encrypted):
+        doc = self._remote_doc
+        if not doc:
+            doc = SoledadDocument(doc_id=self._remote_doc_id())
+        doc.content = encrypted
+        db = self._shared_db
+        if not db:
+            logger.warn('no shared db found')
+            return
+        db.put_doc(doc)
diff --git a/client/src/leap/soledad/client/_secrets/util.py b/client/src/leap/soledad/client/_secrets/util.py
new file mode 100644
index 00000000..f75b2bb6
--- /dev/null
+++ b/client/src/leap/soledad/client/_secrets/util.py
@@ -0,0 +1,46 @@
+# -*- coding:utf-8 -*-
+# _secrets/util.py
+# Copyright (C) 2016 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/>.
+
+
+from leap.soledad.client import events
+
+
+class SecretsError(Exception):
+    pass
+
+
+def emit(verb):
+    def _decorator(method):
+        def _decorated(self, *args, **kwargs):
+
+            # emit starting event
+            user_data = self._user_data
+            name = 'SOLEDAD_' + verb.upper() + '_KEYS'
+            event = getattr(events, name)
+            events.emit_async(event, user_data)
+
+            # run the method
+            result = method(self, *args, **kwargs)
+
+            # emit a finished event
+            name = 'SOLEDAD_DONE_' + verb.upper() + '_KEYS'
+            event = getattr(events, name)
+            events.emit_async(event, user_data)
+
+            return result
+        return _decorated
+    return _decorator
diff --git a/client/src/leap/soledad/client/api.py b/client/src/leap/soledad/client/api.py
index da6eec66..2e1d1cd3 100644
--- a/client/src/leap/soledad/client/api.py
+++ b/client/src/leap/soledad/client/api.py
@@ -45,7 +45,6 @@ from zope.interface import implements
 from leap.common.config import get_path_prefix
 from leap.common.plugins import collect_plugins
 
-from leap.soledad.common import SHARED_DB_NAME
 from leap.soledad.common import soledad_assert
 from leap.soledad.common import soledad_assert_type
 from leap.soledad.common.log import getLogger
@@ -57,8 +56,7 @@ from leap.soledad.client import adbapi
 from leap.soledad.client import events as soledad_events
 from leap.soledad.client import interfaces as soledad_interfaces
 from leap.soledad.client import sqlcipher
-from leap.soledad.client.secrets import SoledadSecrets
-from leap.soledad.client.shared_db import SoledadSharedDatabase
+from leap.soledad.client._secrets import Secrets
 from leap.soledad.client._crypto import SoledadCrypto
 
 logger = getLogger(__name__)
@@ -130,7 +128,7 @@ class Soledad(object):
 
     def __init__(self, uuid, passphrase, secrets_path, local_db_path,
                  server_url, cert_file, shared_db=None,
-                 auth_token=None, syncable=True):
+                 auth_token=None):
         """
         Initialize configuration, cryptographic keys and dbs.
 
@@ -185,8 +183,6 @@ class Soledad(object):
         self._secrets_path = None
         self._dbsyncer = None
 
-        self.shared_db = shared_db
-
         # configure SSL certificate
         global SOLEDAD_CERT
         SOLEDAD_CERT = cert_file
@@ -198,21 +194,15 @@ class Soledad(object):
 
         self._secrets_path = secrets_path
 
-        # Initialize shared recovery database
-        self.init_shared_db(server_url, uuid, self._creds, syncable=syncable)
-
-        # The following can raise BootstrapSequenceError, that will be
-        # propagated upwards.
-        self._init_secrets()
+        self._init_secrets(shared_db=shared_db)
 
-        self._crypto = SoledadCrypto(self._secrets.remote_storage_secret)
+        self._crypto = SoledadCrypto(self._secrets.remote)
 
         try:
             # initialize database access, trap any problems so we can shutdown
             # smoothly.
             self._init_u1db_sqlcipher_backend()
-            if syncable:
-                self._init_u1db_syncer()
+            self._init_u1db_syncer()
         except DatabaseAccessError:
             # oops! something went wrong with backend initialization. We
             # have to close any thread-related stuff we have already opened
@@ -255,14 +245,13 @@ class Soledad(object):
         for path in paths:
             create_path_if_not_exists(path)
 
-    def _init_secrets(self):
+    def _init_secrets(self, shared_db=None):
         """
         Initialize Soledad secrets.
         """
-        self._secrets = SoledadSecrets(
-            self.uuid, self._passphrase, self._secrets_path,
-            self.shared_db, userid=self.userid)
-        self._secrets.bootstrap()
+        self._secrets = Secrets(
+            self._uuid, self._passphrase, self._server_url, self._secrets_path,
+            self._creds, self.userid, shared_db=shared_db)
 
     def _init_u1db_sqlcipher_backend(self):
         """
@@ -279,7 +268,7 @@ class Soledad(object):
         """
         tohex = binascii.b2a_hex
         # sqlcipher only accepts the hex version
-        key = tohex(self._secrets.get_local_storage_key())
+        key = tohex(self._secrets.local)
 
         opts = sqlcipher.SQLCipherOptions(
             self._local_db_path, key,
@@ -659,21 +648,6 @@ class Soledad(object):
     # ISyncableStorage
     #
 
-    def set_syncable(self, syncable):
-        """
-        Toggle the syncable state for this database.
-
-        This can be used to start a database with offline state and switch it
-        online afterwards. Or the opposite: stop syncs when connection is lost.
-
-        :param syncable: new status for syncable.
-        :type syncable: bool
-        """
-        # TODO should check that we've got a token!
-        self.shared_db.syncable = syncable
-        if syncable and not self._dbsyncer:
-            self._init_u1db_syncer()
-
     def sync(self):
         """
         Synchronize documents with the server replica.
@@ -760,13 +734,6 @@ class Soledad(object):
         """
         return self.sync_lock.locked
 
-    @property
-    def syncable(self):
-        if self.shared_db:
-            return self.shared_db.syncable
-        else:
-            return False
-
     def _set_token(self, token):
         """
         Set the authentication token for remote database access.
@@ -803,58 +770,13 @@ class Soledad(object):
     # ISecretsStorage
     #
 
-    def init_shared_db(self, server_url, uuid, creds, syncable=True):
-        """
-        Initialize the shared database.
-
-        :param server_url: URL of the remote database.
-        :type server_url: str
-        :param uuid: The user's unique id.
-        :type uuid: str
-        :param creds: A tuple containing the authentication method and
-            credentials.
-        :type creds: tuple
-        :param syncable:
-            If syncable is False, the database will not attempt to sync against
-            a remote replica.
-        :type syncable: bool
-        """
-        # only case this is False is for testing purposes
-        if self.shared_db is None:
-            shared_db_url = urlparse.urljoin(server_url, SHARED_DB_NAME)
-            self.shared_db = SoledadSharedDatabase.open_database(
-                shared_db_url,
-                uuid,
-                creds=creds,
-                syncable=syncable)
-
-    @property
-    def storage_secret(self):
-        """
-        Return the secret used for local storage encryption.
-
-        :return: The secret used for local storage encryption.
-        :rtype: str
-        """
-        return self._secrets.storage_secret
-
-    @property
-    def remote_storage_secret(self):
-        """
-        Return the secret used for encryption of remotely stored data.
-
-        :return: The secret used for remote storage  encryption.
-        :rtype: str
-        """
-        return self._secrets.remote_storage_secret
-
     @property
     def secrets(self):
         """
         Return the secrets object.
 
         :return: The secrets object.
-        :rtype: SoledadSecrets
+        :rtype: Secrets
         """
         return self._secrets
 
diff --git a/client/src/leap/soledad/client/interfaces.py b/client/src/leap/soledad/client/interfaces.py
index 82927ff4..1be47df7 100644
--- a/client/src/leap/soledad/client/interfaces.py
+++ b/client/src/leap/soledad/client/interfaces.py
@@ -351,28 +351,12 @@ class ISecretsStorage(Interface):
     secrets_file_name = Attribute(
         "The name of the file where the storage secrets will be stored")
 
-    storage_secret = Attribute("")
-    remote_storage_secret = Attribute("")
-    shared_db = Attribute("The shared db object")
-
     # XXX this used internally from secrets, so it might be good to preserve
     # as a public boundary with other components.
 
     # We should also probably document its interface.
     secrets = Attribute("A SoledadSecrets object containing access to secrets")
 
-    def init_shared_db(self, server_url, uuid, creds):
-        """
-        Initialize the shared recovery database.
-
-        :param server_url:
-        :type server_url:
-        :param uuid:
-        :type uuid:
-        :param creds:
-        :type creds:
-        """
-
     def change_passphrase(self, new_passphrase):
         """
         Change the passphrase that encrypts the storage secret.
@@ -382,7 +366,3 @@ class ISecretsStorage(Interface):
 
         :raise NoStorageSecret: Raised if there's no storage secret available.
         """
-
-    # XXX not in use. Uncomment if we ever decide to allow
-    # multiple secrets.
-    # secret_id = Attribute("The id of the storage secret to be used")
diff --git a/client/src/leap/soledad/client/secrets.py b/client/src/leap/soledad/client/secrets.py
deleted file mode 100644
index 3fe98c64..00000000
--- a/client/src/leap/soledad/client/secrets.py
+++ /dev/null
@@ -1,794 +0,0 @@
-# -*- coding: utf-8 -*-
-# secrets.py
-# Copyright (C) 2014 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/>.
-
-
-"""
-Soledad secrets handling.
-"""
-
-
-import os
-import scrypt
-import binascii
-import errno
-import json
-
-from hashlib import sha256
-
-from leap.soledad.common import soledad_assert
-from leap.soledad.common import soledad_assert_type
-from leap.soledad.common import document
-from leap.soledad.common.log import getLogger
-from leap.soledad.client import events
-from leap.soledad.client import _crypto
-
-
-logger = getLogger(__name__)
-
-
-#
-# Exceptions
-#
-
-
-class SecretsException(Exception):
-
-    """
-    Generic exception type raised by this module.
-    """
-
-
-class NoStorageSecret(SecretsException):
-
-    """
-    Raised when trying to use a storage secret but none is available.
-    """
-    pass
-
-
-class PassphraseTooShort(SecretsException):
-
-    """
-    Raised when trying to change the passphrase but the provided passphrase is
-    too short.
-    """
-
-
-class BootstrapSequenceError(SecretsException):
-
-    """
-    Raised when an attempt to generate a secret and store it in a recovery
-    document on server failed.
-    """
-
-
-#
-# Secrets handler
-#
-
-
-class SoledadSecrets(object):
-
-    """
-    Soledad secrets handler.
-
-    The first C{self.REMOTE_STORAGE_SECRET_LENGTH} bytes of the storage
-    secret are used for remote storage encryption. We use the next
-    C{self.LOCAL_STORAGE_SECRET} bytes to derive a key for local storage.
-    From these bytes, the first C{self.SALT_LENGTH} bytes are used as the
-    salt and the rest as the password for the scrypt hashing.
-    """
-
-    LOCAL_STORAGE_SECRET_LENGTH = 512
-    """
-    The length, in bytes, of the secret used to derive a passphrase for the
-    SQLCipher database.
-    """
-
-    REMOTE_STORAGE_SECRET_LENGTH = 512
-    """
-    The length, in bytes, of the secret used to derive an encryption key for
-    remote storage.
-    """
-
-    SALT_LENGTH = 64
-    """
-    The length, in bytes, of the salt used to derive the key for the storage
-    secret encryption.
-    """
-
-    GEN_SECRET_LENGTH = LOCAL_STORAGE_SECRET_LENGTH \
-        + REMOTE_STORAGE_SECRET_LENGTH \
-        + SALT_LENGTH  # for sync db
-    """
-    The length, in bytes, of the secret to be generated. This includes local
-    and remote secrets, and the salt for deriving the sync db secret.
-    """
-
-    MINIMUM_PASSPHRASE_LENGTH = 6
-    """
-    The minimum length, in bytes, for a passphrase. The passphrase length is
-    only checked when the user changes her passphrase, not when she
-    instantiates Soledad.
-    """
-
-    SEPARATOR = ":"
-    """
-    A separator used for storing the encryption initial value prepended to the
-    ciphertext.
-    """
-
-    UUID_KEY = 'uuid'
-    STORAGE_SECRETS_KEY = 'storage_secrets'
-    ACTIVE_SECRET_KEY = 'active_secret'
-    SECRET_KEY = 'secret'
-    CIPHER_KEY = 'cipher'
-    LENGTH_KEY = 'length'
-    KDF_KEY = 'kdf'
-    KDF_SALT_KEY = 'kdf_salt'
-    KDF_LENGTH_KEY = 'kdf_length'
-    KDF_SCRYPT = 'scrypt'
-    CIPHER_AES256 = 'aes256'  # deprecated, AES-CTR
-    CIPHER_AES256_GCM = _crypto.ENC_METHOD.aes_256_gcm
-    RECOVERY_DOC_VERSION_KEY = 'version'
-    RECOVERY_DOC_VERSION = 1
-    """
-    Keys used to access storage secrets in recovery documents.
-    """
-
-    def __init__(self, uuid, passphrase, secrets_path, shared_db, userid=None):
-        """
-        Initialize the secrets manager.
-
-        :param uuid: User's unique id.
-        :type uuid: str
-        :param passphrase: The passphrase for locking and unlocking encryption
-                           secrets for local and remote storage.
-        :type passphrase: unicode
-        :param secrets_path: Path for storing encrypted key used for
-                             symmetric encryption.
-        :type secrets_path: str
-        :param shared_db: The shared database that stores user secrets.
-        :type shared_db: leap.soledad.client.shared_db.SoledadSharedDatabase
-        """
-        self._uuid = uuid
-        self._userid = userid
-        self._passphrase = passphrase
-        self._secrets_path = secrets_path
-        self._shared_db = shared_db
-        self._secrets = {}
-        self._secret_id = None
-
-    def bootstrap(self):
-        """
-        Bootstrap secrets.
-
-        Soledad secrets bootstrap is the following sequence of stages:
-
-        * stage 1 - local secret loading:
-            - if secrets exist locally, load them.
-        * stage 2 - remote secret loading:
-            - else, if secrets exist in server, download them.
-        * stage 3 - secret generation:
-            - else, generate a new secret and store in server.
-
-        This method decides which bootstrap stages have already been performed
-        and performs the missing ones in order.
-
-        :raise BootstrapSequenceError: Raised when the secret generation and
-            storage on server sequence has failed for some reason.
-        """
-        # STAGE 1 - verify if secrets exist locally
-        try:
-            logger.info("trying to load secrets from local storage...")
-            version = self._load_secrets_from_local_file()
-            # eventually migrate local and remote stored documents from old
-            # format version
-            if version < self.RECOVERY_DOC_VERSION:
-                self._store_secrets()
-                self._upload_crypto_secrets()
-            logger.info("found secrets in local storage")
-            return
-
-        except NoStorageSecret:
-            logger.info("could not find secrets in local storage")
-
-        # STAGE 2 - there are no secrets in local storage and this is the
-        #           first time we are running soledad with the specified
-        #           secrets_path. Try to fetch encrypted secrets from
-        #           server.
-        try:
-            logger.info('trying to fetch secrets from remote storage...')
-            version = self._download_crypto_secrets()
-            self._store_secrets()
-            # eventually migrate remote stored document from old format
-            # version
-            if version < self.RECOVERY_DOC_VERSION:
-                self._upload_crypto_secrets()
-            logger.info('found secrets in remote storage.')
-            return
-        except NoStorageSecret:
-            logger.info("could not find secrets in remote storage.")
-
-        # STAGE 3 - there are no secrets in server also, so we want to
-        #           generate the secrets and store them in the remote
-        #           db.
-        logger.info("generating secrets...")
-        self._gen_crypto_secrets()
-        logger.info("uploading secrets...")
-        self._upload_crypto_secrets()
-
-    def _has_secret(self):
-        """
-        Return whether there is a storage secret available for use or not.
-
-        :return: Whether there's a storage secret for symmetric encryption.
-        :rtype: bool
-        """
-        return self.storage_secret is not None
-
-    def _maybe_set_active_secret(self, active_secret):
-        """
-        If no secret_id is already set, choose the passed active secret, or
-        just choose first secret available if none.
-        """
-        if not self._secret_id:
-            if not active_secret:
-                active_secret = self._secrets.items()[0][0]
-            self.set_secret_id(active_secret)
-
-    def _load_secrets_from_local_file(self):
-        """
-        Load storage secrets from local file.
-
-        :return version: The version of the locally stored recovery document.
-
-        :raise NoStorageSecret: Raised if there are no secrets available in
-                                local storage.
-        """
-        # check if secrets file exists and we can read it
-        if not os.path.isfile(self._secrets_path):
-            raise NoStorageSecret
-
-        # read storage secrets from file
-        content = None
-        with open(self._secrets_path, 'r') as f:
-            content = json.loads(f.read())
-        _, active_secret, version = self._import_recovery_document(content)
-
-        self._maybe_set_active_secret(active_secret)
-
-        return version
-
-    def _download_crypto_secrets(self):
-        """
-        Download crypto secrets.
-
-        :return version: The version of the remotelly stored recovery document.
-
-        :raise NoStorageSecret: Raised if there are no secrets available in
-                                remote storage.
-        """
-        doc = None
-        if self._shared_db.syncable:
-            doc = self._get_secrets_from_shared_db()
-
-        if doc is None:
-            raise NoStorageSecret
-
-        _, active_secret, version = self._import_recovery_document(doc.content)
-        self._maybe_set_active_secret(active_secret)
-
-        return version
-
-    def _gen_crypto_secrets(self):
-        """
-        Generate the crypto secrets.
-        """
-        logger.info('no cryptographic secrets found, creating new secrets...')
-        secret_id = self._gen_secret()
-        self.set_secret_id(secret_id)
-
-    def _upload_crypto_secrets(self):
-        """
-        Send crypto secrets to shared db.
-
-        :raises BootstrapSequenceError: Raised when unable to store secrets in
-                                        shared database.
-        """
-        if self._shared_db.syncable:
-            try:
-                self._put_secrets_in_shared_db()
-            except Exception as ex:
-                # storing generated secret in shared db failed for
-                # some reason, so we erase the generated secret and
-                # raise.
-                try:
-                    os.unlink(self._secrets_path)
-                except OSError as e:
-                    if e.errno != errno.ENOENT:
-                        # no such file or directory
-                        logger.exception(e)
-                logger.exception(ex)
-                raise BootstrapSequenceError(
-                    'Could not store generated secret in the shared '
-                    'database, bailing out...')
-
-    #
-    # Shared DB related methods
-    #
-
-    def _shared_db_doc_id(self):
-        """
-        Calculate the doc_id of the document in the shared db that stores key
-        material.
-
-        :return: the hash
-        :rtype: str
-        """
-        return sha256(
-            '%s%s' %
-            (self._passphrase_as_string(), self._uuid)).hexdigest()
-
-    def _export_recovery_document(self, cipher=None):
-        """
-        Export the storage secrets.
-
-        Current format of recovery document has the following structure:
-
-            {
-                'storage_secrets': {
-                    '<storage_secret id>': {
-                        'cipher': 'aes256',
-                        'length': <secret length>,
-                        'secret': '<encrypted storage_secret>',
-                    },
-                },
-                'active_secret': '<secret_id>',
-                'version': '<recovery document format version>',
-            }
-
-        Note that multiple storage secrets might be stored in one recovery
-        document.
-
-        :param cipher: (Optional) The ciper to use. Defaults to AES256
-        :type cipher: str
-
-        :return: The recovery document.
-        :rtype: dict
-        """
-        # encrypt secrets
-        encrypted_secrets = {}
-        for secret_id in self._secrets:
-            encrypted_secrets[secret_id] = self._encrypt_storage_secret(
-                self._secrets[secret_id], doc_cipher=cipher)
-        # create the recovery document
-        data = {
-            self.STORAGE_SECRETS_KEY: encrypted_secrets,
-            self.ACTIVE_SECRET_KEY: self._secret_id,
-            self.RECOVERY_DOC_VERSION_KEY: self.RECOVERY_DOC_VERSION,
-        }
-        return data
-
-    def _import_recovery_document(self, data):
-        """
-        Import storage secrets for symmetric encryption from a recovery
-        document.
-
-        Note that this method does not store the imported data on disk. For
-        that, use C{self._store_secrets()}.
-
-        :param data: The recovery document.
-        :type data: dict
-
-        :return: A tuple containing the number of imported secrets, the
-                 secret_id of the last active secret, and the recovery
-                 document format version.
-        :rtype: (int, str, int)
-        """
-        soledad_assert(self.STORAGE_SECRETS_KEY in data)
-        version = data.get(self.RECOVERY_DOC_VERSION_KEY, 1)
-        meth = getattr(self, '_import_recovery_document_version_%d' % version)
-        secret_count, active_secret = meth(data)
-        return secret_count, active_secret, version
-
-    def _import_recovery_document_version_1(self, data):
-        """
-        Import storage secrets for symmetric encryption from a recovery
-        document with format version 1.
-
-        Version 1 of recovery document has the following structure:
-
-            {
-                'storage_secrets': {
-                    '<storage_secret id>': {
-                        'cipher': 'aes256',
-                        'length': <secret length>,
-                        'secret': '<encrypted storage_secret>',
-                    },
-                },
-                'active_secret': '<secret_id>',
-                'version': '<recovery document format version>',
-            }
-
-        :param data: The recovery document.
-        :type data: dict
-
-        :return: A tuple containing the number of imported secrets, the
-                 secret_id of the last active secret, and the recovery
-                 document format version.
-        :rtype: (int, str, int)
-        """
-        # include secrets in the secret pool.
-        secret_count = 0
-        secrets = data[self.STORAGE_SECRETS_KEY].items()
-        active_secret = None
-        # XXX remove check for existence of key (included for backwards
-        # compatibility)
-        if self.ACTIVE_SECRET_KEY in data:
-            active_secret = data[self.ACTIVE_SECRET_KEY]
-        for secret_id, encrypted_secret in secrets:
-            if secret_id not in self._secrets:
-                try:
-                    self._secrets[secret_id] = \
-                        self._decrypt_storage_secret_version_1(
-                            encrypted_secret)
-                    secret_count += 1
-                except SecretsException as e:
-                    logger.error("failed to decrypt storage secret: %s"
-                                 % str(e))
-                    raise e
-        return secret_count, active_secret
-
-    def _get_secrets_from_shared_db(self):
-        """
-        Retrieve the document with encrypted key material from the shared
-        database.
-
-        :return: a document with encrypted key material in its contents
-        :rtype: document.SoledadDocument
-        """
-        user_data = self._get_user_data()
-        events.emit_async(events.SOLEDAD_DOWNLOADING_KEYS, user_data)
-        db = self._shared_db
-        if not db:
-            logger.warn('no shared db found')
-            return
-        doc = db.get_doc(self._shared_db_doc_id())
-        user_data = {'userid': self._userid, 'uuid': self._uuid}
-        events.emit_async(events.SOLEDAD_DONE_DOWNLOADING_KEYS, user_data)
-        return doc
-
-    def _put_secrets_in_shared_db(self):
-        """
-        Assert local keys are the same as shared db's ones.
-
-        Try to fetch keys from shared recovery database. If they already exist
-        in the remote db, assert that that data is the same as local data.
-        Otherwise, upload keys to shared recovery database.
-        """
-        soledad_assert(
-            self._has_secret(),
-            'Tried to send keys to server but they don\'t exist in local '
-            'storage.')
-        # try to get secrets doc from server, otherwise create it
-        doc = self._get_secrets_from_shared_db()
-        if doc is None:
-            doc = document.SoledadDocument(
-                doc_id=self._shared_db_doc_id())
-        # fill doc with encrypted secrets
-        doc.content = self._export_recovery_document()
-        # upload secrets to server
-        user_data = self._get_user_data()
-        events.emit_async(events.SOLEDAD_UPLOADING_KEYS, user_data)
-        db = self._shared_db
-        if not db:
-            logger.warn('no shared db found')
-            return
-        db.put_doc(doc)
-        events.emit_async(events.SOLEDAD_DONE_UPLOADING_KEYS, user_data)
-
-    #
-    # Management of secret for symmetric encryption.
-    #
-
-    def _decrypt_storage_secret_version_1(self, encrypted_secret_dict):
-        """
-        Decrypt the storage secret.
-
-        Storage secret is encrypted before being stored. This method decrypts
-        and returns the decrypted storage secret.
-
-        Version 1 of storage secret format has the following structure:
-
-            '<storage_secret id>': {
-                'cipher': 'aes256',
-                'length': <secret length>,
-                'secret': '<encrypted storage_secret>',
-            },
-
-        :param encrypted_secret_dict: The encrypted storage secret.
-        :type encrypted_secret_dict:  dict
-
-        :return: The decrypted storage secret.
-        :rtype: str
-
-        :raise SecretsException: Raised in case the decryption of the storage
-                                 secret fails for some reason.
-        """
-        # calculate the encryption key
-        if encrypted_secret_dict[self.KDF_KEY] != self.KDF_SCRYPT:
-            raise SecretsException("Unknown KDF in stored secret.")
-        key = scrypt.hash(
-            self._passphrase_as_string(),
-            # the salt is stored base64 encoded
-            binascii.a2b_base64(
-                encrypted_secret_dict[self.KDF_SALT_KEY]),
-            buflen=32,  # we need a key with 256 bits (32 bytes).
-        )
-        if encrypted_secret_dict[self.KDF_LENGTH_KEY] != len(key):
-            raise SecretsException("Wrong length of decryption key.")
-        supported_ciphers = [self.CIPHER_AES256, self.CIPHER_AES256_GCM]
-        doc_cipher = encrypted_secret_dict[self.CIPHER_KEY]
-        if doc_cipher not in supported_ciphers:
-            raise SecretsException("Unknown cipher in stored secret.")
-        # recover the initial value and ciphertext
-        iv, ciphertext = encrypted_secret_dict[self.SECRET_KEY].split(
-            self.SEPARATOR, 1)
-        ciphertext = binascii.a2b_base64(ciphertext)
-        try:
-            decrypted_secret = _crypto.decrypt_sym(
-                ciphertext, key, iv, doc_cipher)
-        except Exception as e:
-            logger.error(e)
-            raise SecretsException("Unable to decrypt secret.")
-        if encrypted_secret_dict[self.LENGTH_KEY] != len(decrypted_secret):
-            raise SecretsException("Wrong length of decrypted secret.")
-        return decrypted_secret
-
-    def _encrypt_storage_secret(self, decrypted_secret, doc_cipher=None):
-        """
-        Encrypt the storage secret.
-
-        An encrypted secret has the following structure:
-
-            {
-                '<secret_id>': {
-                        'kdf': 'scrypt',
-                        'kdf_salt': '<b64 repr of salt>'
-                        'kdf_length': <key length>
-                        'cipher': 'aes256',
-                        'length': <secret length>,
-                        'secret': '<encrypted b64 repr of storage_secret>',
-                }
-            }
-
-        :param decrypted_secret: The decrypted storage secret.
-        :type decrypted_secret: str
-        :param cipher: (Optional) The ciper to use. Defaults to AES256
-        :type cipher: str
-
-        :return: The encrypted storage secret.
-        :rtype: dict
-        """
-        # generate random salt
-        salt = os.urandom(self.SALT_LENGTH)
-        # get a 256-bit key
-        key = scrypt.hash(self._passphrase_as_string(), salt, buflen=32)
-        doc_cipher = doc_cipher or self.CIPHER_AES256_GCM
-        iv, ciphertext = _crypto.encrypt_sym(decrypted_secret, key, doc_cipher)
-        ciphertext = binascii.b2a_base64(ciphertext)
-        encrypted_secret_dict = {
-            # leap.soledad.crypto submodule uses AES256 for symmetric
-            # encryption.
-            self.KDF_KEY: self.KDF_SCRYPT,
-            self.KDF_SALT_KEY: binascii.b2a_base64(salt),
-            self.KDF_LENGTH_KEY: len(key),
-            self.CIPHER_KEY: doc_cipher,
-            self.LENGTH_KEY: len(decrypted_secret),
-            self.SECRET_KEY: self.SEPARATOR.join([str(iv), ciphertext])
-        }
-        return encrypted_secret_dict
-
-    @property
-    def storage_secret(self):
-        """
-        Return the storage secret.
-
-        :return: The decrypted storage secret.
-        :rtype: str
-        """
-        return self._secrets.get(self._secret_id)
-
-    def set_secret_id(self, secret_id):
-        """
-        Define the id of the storage secret to be used.
-
-        This method will also replace the secret in the crypto object.
-
-        :param secret_id: The id of the storage secret to be used.
-        :type secret_id: str
-        """
-        self._secret_id = secret_id
-
-    def _gen_secret(self):
-        """
-        Generate a secret for symmetric encryption and store in a local
-        encrypted file.
-
-        This method emits the following events.signals:
-
-            * SOLEDAD_CREATING_KEYS
-            * SOLEDAD_DONE_CREATING_KEYS
-
-        :return: The id of the generated secret.
-        :rtype: str
-        """
-        user_data = self._get_user_data()
-        events.emit_async(events.SOLEDAD_CREATING_KEYS, user_data)
-        # generate random secret
-        secret = os.urandom(self.GEN_SECRET_LENGTH)
-        secret_id = sha256(secret).hexdigest()
-        self._secrets[secret_id] = secret
-        self._store_secrets()
-        events.emit_async(events.SOLEDAD_DONE_CREATING_KEYS, user_data)
-        return secret_id
-
-    def _store_secrets(self):
-        """
-        Store secrets in C{Soledad.STORAGE_SECRETS_FILE_PATH}.
-        """
-        with open(self._secrets_path, 'w') as f:
-            f.write(
-                json.dumps(
-                    self._export_recovery_document()))
-
-    def change_passphrase(self, new_passphrase):
-        """
-        Change the passphrase that encrypts the storage secret.
-
-        :param new_passphrase: The new passphrase.
-        :type new_passphrase: unicode
-
-        :raise NoStorageSecret: Raised if there's no storage secret available.
-        """
-        # TODO: maybe we want to add more checks to guarantee passphrase is
-        # reasonable?
-        soledad_assert_type(new_passphrase, unicode)
-        if len(new_passphrase) < self.MINIMUM_PASSPHRASE_LENGTH:
-            raise PassphraseTooShort(
-                'Passphrase must be at least %d characters long!' %
-                self.MINIMUM_PASSPHRASE_LENGTH)
-        # ensure there's a secret for which the passphrase will be changed.
-        if not self._has_secret():
-            raise NoStorageSecret()
-        self._passphrase = new_passphrase
-        self._store_secrets()
-        self._put_secrets_in_shared_db()
-
-    #
-    # Setters and getters
-    #
-
-    @property
-    def secret_id(self):
-        return self._secret_id
-
-    def _get_secrets_path(self):
-        return self._secrets_path
-
-    def _set_secrets_path(self, secrets_path):
-        self._secrets_path = secrets_path
-
-    secrets_path = property(
-        _get_secrets_path,
-        _set_secrets_path,
-        doc='The path for the file containing the encrypted symmetric secret.')
-
-    @property
-    def passphrase(self):
-        """
-        Return the passphrase for locking and unlocking encryption secrets for
-        local and remote storage.
-        """
-        return self._passphrase
-
-    def _passphrase_as_string(self):
-        return self._passphrase.encode('utf-8')
-
-    #
-    # remote storage secret
-    #
-
-    @property
-    def remote_storage_secret(self):
-        """
-        Return the secret for remote storage.
-        """
-        key_start = 0
-        key_end = self.REMOTE_STORAGE_SECRET_LENGTH
-        return self.storage_secret[key_start:key_end]
-
-    #
-    # local storage key
-    #
-
-    def _get_local_storage_secret(self):
-        """
-        Return the local storage secret.
-
-        :return: The local storage secret.
-        :rtype: str
-        """
-        secret_len = self.REMOTE_STORAGE_SECRET_LENGTH
-        lsecret_len = self.LOCAL_STORAGE_SECRET_LENGTH
-        pwd_start = secret_len + self.SALT_LENGTH
-        pwd_end = secret_len + lsecret_len
-        return self.storage_secret[pwd_start:pwd_end]
-
-    def _get_local_storage_salt(self):
-        """
-        Return the local storage salt.
-
-        :return: The local storage salt.
-        :rtype: str
-        """
-        salt_start = self.REMOTE_STORAGE_SECRET_LENGTH
-        salt_end = salt_start + self.SALT_LENGTH
-        return self.storage_secret[salt_start:salt_end]
-
-    def get_local_storage_key(self):
-        """
-        Return the local storage key derived from the local storage secret.
-
-        :return: The key for protecting the local database.
-        :rtype: str
-        """
-        return scrypt.hash(
-            password=self._get_local_storage_secret(),
-            salt=self._get_local_storage_salt(),
-            buflen=32,  # we need a key with 256 bits (32 bytes)
-        )
-
-    #
-    # sync db key
-    #
-
-    def _get_sync_db_salt(self):
-        """
-        Return the salt for sync db.
-        """
-        salt_start = self.LOCAL_STORAGE_SECRET_LENGTH \
-            + self.REMOTE_STORAGE_SECRET_LENGTH
-        salt_end = salt_start + self.SALT_LENGTH
-        return self.storage_secret[salt_start:salt_end]
-
-    def get_sync_db_key(self):
-        """
-        Return the key for protecting the sync database.
-
-        :return: The key for protecting the sync database.
-        :rtype: str
-        """
-        return scrypt.hash(
-            password=self._get_local_storage_secret(),
-            salt=self._get_sync_db_salt(),
-            buflen=32,  # we need a key with 256 bits (32 bytes)
-        )
-
-    def _get_user_data(self):
-        return {'uuid': self._uuid, 'userid': self._userid}
diff --git a/client/src/leap/soledad/client/shared_db.py b/client/src/leap/soledad/client/shared_db.py
index d43db045..52b226b9 100644
--- a/client/src/leap/soledad/client/shared_db.py
+++ b/client/src/leap/soledad/client/shared_db.py
@@ -17,7 +17,7 @@
 """
 A shared database for storing/retrieving encrypted key material.
 """
-from leap.soledad.common.l2db.remote import http_database
+from leap.soledad.common.l2db.remote.http_database import HTTPDatabase
 
 from leap.soledad.client.auth import TokenBasedAuth
 
@@ -47,7 +47,7 @@ class ImproperlyConfiguredError(Exception):
     """
 
 
-class SoledadSharedDatabase(http_database.HTTPDatabase, TokenBasedAuth):
+class SoledadSharedDatabase(HTTPDatabase, TokenBasedAuth):
     """
     This is a shared recovery database that enables users to store their
     encryption secrets in the server and retrieve them afterwards.
@@ -134,20 +134,16 @@ class SoledadSharedDatabase(http_database.HTTPDatabase, TokenBasedAuth):
         """
         raise Unauthorized("Can't delete shared database.")
 
-    def __init__(self, url, uuid, document_factory=None, creds=None):
+    def __init__(self, url, document_factory=None, creds=None):
         """
         Initialize database with auth token and encryption powers.
 
         :param url: URL of the remote database.
         :type url: str
-        :param uuid: The user's unique id.
-        :type uuid: str
         :param document_factory: A factory for U1BD documents.
         :type document_factory: u1db.Document
         :param creds: A tuple containing the authentication method and
             credentials.
         :type creds: tuple
         """
-        http_database.HTTPDatabase.__init__(self, url, document_factory,
-                                            creds)
-        self._uuid = uuid
+        HTTPDatabase.__init__(self, url, document_factory, creds)