python-u1dbcipher

Python bindings for libu1db, with support for SQLCipher.

This is done for the Soledad (Synchronization Of Locally Encrypted Data Among Devices) component of the LEAP project.

A previous attempt at this same goal is pysqlcipher, but the python u1db implementation is severely limited in performance when it comes to sync several hundreds of documents.

Right now this is an experimental package with a couple of trivial modifications to the original u1db code:

• extending a little bit the cython bindings that can be found in the test folder from the ubuntu u1db reference implementation written in python
• patching libu1db to initialize SQLCipher with the needed crypto pragmas.

Install

Build patched u1db library:

cython u1dbcipher/_u1db.pyc
cmake .
make u1db

Build c extension:

python setup.py build

Install python package:

python setup.py install

Using the database interface

Inserting and retrieving documents

Note that you have to give an extra argument to the open function for the encryption key:

import u1dbcipher as u1db
db = u1db.open("/tmp/test.db", "sekret")
doc = db.create_doc({'theanswer': 42})
print "document id: %s" % doc.doc_id
print "document revision: %s" % doc.rev

doc2 = db.get_doc(doc.doc_id)
print (doc == doc2)

You can visually check that the database file is encrypted:

hexdump -C /tmp/test.db | head                                                                

00000000  00 04 6b b3 3a 7f af 4e  1b 37 b7 c2 40 90 18 37  |..k.:..N.7..@..7|
00000010  2a 4d 8c e3 1b cd 60 7c  cf 84 c1 57 ef cb 54 91  |*M....`|...W..T.|
00000020  5a 48 27 0d 36 42 85 90  82 a8 a4 20 3d ec 2f e4  |ZH'.6B..... =./.|
00000030  92 ac 64 f3 d4 c5 fb c7  96 ef 84 21 91 61 a8 f1  |..d........!.a..|
00000040  23 70 d3 00 3b fd f3 f7  29 1f 8d 86 e5 9a 03 e9  |#p..;...).......|
00000050  23 8e 85 60 59 c5 f2 e5  b4 75 60 ec 4c a1 bc 5c  |#..`Y....u`.L..\|
00000060  dc 93 6f 84 ed 78 34 4b  bb 79 2d bd 67 d5 32 82  |..o..x4K.y-.g.2.|
00000070  eb 4f ec b3 75 07 fb 52  16 b6 0f 27 0a e2 89 4c  |.O..u..R...'...L|
00000080  35 6d c0 00 23 63 3b 96  83 83 6f e1 19 fd 0f 44  |5m..#c;...o....D|
00000090  b1 69 82 ab 12 de 5d 4a  60 2a 9d f2 31 58 60 b3  |.i....]J`*..1X`.|

Dependencies

if python-cjson is avaiable, it will be used instead of builtin json module.