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
|
.. index:: windows; nt hash
==================================================================
:class:`passlib.hash.nthash` - Windows' NT-HASH
==================================================================
.. versionadded:: 1.6
.. warning::
This scheme is very weak, the :mod:`~passlib.utils.md4` digest
it is based on has been severely compromised for many years.
It should be used for compatibility with existing systems;
**do not use** in new code.
.. currentmodule:: passlib.hash
This class implements the NT-HASH algorithm, used by Microsoft Windows NT
and successors to store user account passwords, supplanting
the much weaker :doc:`lmhash <passlib.hash.lmhash>` algorithm.
This class can be used directly as follows::
>>> from passlib.hash import nthash
>>> # encrypt password
>>> h = nthash.encrypt("password")
>>> h
'8846f7eaee8fb117ad06bdd830b7586c'
>>> # verify password
>>> nthash.verify("password", h)
True
>>> nthash.verify("secret", h)
False
.. seealso:: the generic :ref:`PasswordHash usage examples <password-hash-examples>`
Interface
=========
.. autoclass:: nthash()
Format & Algorithm
==================
A nthash consists of 32 hexidecimal digits, which encode the digest.
An example hash (of ``password``) is ``8846f7eaee8fb117ad06bdd830b7586c``.
The digest is calculated by encoding the secret using ``UTF-16-LE``,
taking the :mod:`~passlib.utils.md4` digest, and then encoding
that as hexidecimal.
FreeBSD Variant
===============
For cross-compatibility, FreeBSD's :func:`!crypt` supports storing
NTHASH digests in a manner compatible with the :ref:`modular-crypt-format`,
to enable administrators to store user passwords in a manner compatible with
the SMB/CIFS protocol. This is accomplished by assigning NTHASH digests the
identifier ``$3$``, and prepending the identifier to the normal (lowercase)
NTHASH digest. An example digest (of ``password``) is
``$3$$8846f7eaee8fb117ad06bdd830b7586c`` (note the doubled ``$$``).
.. data:: bsd_nthash
This object supports FreeBSD's representation of NTHASH
(which is compatible with the :ref:`modular-crypt-format`),
and follows the :ref:`password-hash-api`.
It has no salt and a single fixed round.
The :meth:`~passlib.ifc.PasswordHash.encrypt` and :meth:`~passlib.ifc.PasswordHash.genconfig` methods accept no optional keywords.
.. versionchanged:: 1.6
This hash was named ``nthash`` under previous releases of Passlib.
Security Issues
===============
This algorithm should be considered *completely* broken:
* It has no salt.
* The MD4 message digest has been severely compromised by collision and
preimage attacks.
* Brute-force and pre-computed attacks exist targeting MD4 hashes in general,
and the encoding used by NTHASH in particular.
|
