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passlib.hash.nthash - Windows' NT-HASH

Danger

This algorithm is dangerously insecure by modern standards. It is trivially broken, and should not be used if at all possible. For new code, see the list of recommended hashes.

This class implements the NT-HASH algorithm, used by Microsoft Windows NT and successors to store user account passwords, supplanting the much weaker lmhash algorithm. This class can be used directly as follows:

from passlib.hash import nthash

# hash password
h = nthash.hash("password")
print(h)
# > '8846f7eaee8fb117ad06bdd830b7586c'

# verify password
print(nthash.verify("password", h))
# > True
print(nthash.verify("secret", h))
# > False

Tip

See the generic PasswordHash usage examples.

Interface

nthash 

nthash(checksum=None, use_defaults=False, **kwds)

This class implements the NT Password hash, and follows the :ref:password-hash-api.

It has no salt and a single fixed round.

The :meth:~passlib.ifc.PasswordHash.hash and :meth:~passlib.ifc.PasswordHash.genconfig methods accept no optional keywords.

Note that while this class outputs lower-case hexadecimal digests, it will accept upper-case digests as well.

encrypt classmethod 

encrypt(*args, **kwds)

Legacy alias for :meth:hash.

.. deprecated:: 1.7 This method was renamed to :meth:!hash in version 1.7. This alias will be removed in version 2.0, and should only be used for compatibility with Passlib 1.3 - 1.6.

parsehash classmethod 

parsehash(hash, checksum=True, sanitize=False)

[experimental method] parse hash into dictionary of settings.

this essentially acts as the inverse of :meth:hash: for most cases, if hash = cls.hash(secret, **opts), then cls.parsehash(hash) will return a dict matching the original options (with the extra keyword checksum).

this method may not work correctly for all hashes, and may not be available on some few. its interface may change in future releases, if it's kept around at all.

Parameters:

  • hash –

    hash to parse

  • checksum –

    include checksum keyword? (defaults to True)

  • sanitize –

    mask data for sensitive fields? (defaults to False)

bitsize classmethod 

bitsize(**kwds)

[experimental method] return info about bitsizes of hash

raw classmethod 

raw(secret)

encode password using MD4-based NTHASH algorithm

Parameters:

  • secret –

    secret as unicode or utf-8 encoded bytes

Returns:

  • –

    returns string of raw bytes

Format & Algorithm

A nthash consists of 32 hexadecimal 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 MD4 digest, and then encoding that as hexadecimal.

FreeBSD Variant

For cross-compatibility, FreeBSD's crypt supports storing NTHASH digests in a manner compatible with the 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$$8846f7eaee8fb117ad06bdd830b7586c (note the doubled $$).

bsd_nthash

This object supports FreeBSD's representation of NTHASH (which is compatible with the modular-crypt-format), and follows the password-hash-api.

It has no salt and a single fixed round.

The hash() and genconfig() methods accept no optional keywords.

Warning

Changed in 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.