Class CRYPT

source code

object --+
         |
        CRYPT

example::

    INPUT(_type='text', _name='name', requires=CRYPT())

encodes the value on validation with a digest.

If no arguments are provided CRYPT uses the MD5 algorithm.
If the key argument is provided the HMAC+MD5 algorithm is used.
If the digest_alg is specified this is used to replace the
MD5 with, for example, SHA512. The digest_alg can be
the name of a hashlib algorithm as a string or the algorithm itself.

min_length is the minimal password length (default 4) - IS_STRONG for serious security
error_message is the message if password is too short

Notice that an empty password is accepted but invalid. It will not allow login back.
Stores junk as hashed password.

Specify an algorithm or by default we will use sha512.

Typical available algorithms:
  md5, sha1, sha224, sha256, sha384, sha512

If salt, it hashes a password with a salt.
If salt is True, this method will automatically generate one.
Either case it returns an encrypted password string in the following format:

  <algorithm>$<salt>$<hash>

Important: hashed password is returned as a LazyCrypt object and computed only if needed.
The LasyCrypt object also knows how to compare itself with an existing salted password

Supports standard algorithms

>>> for alg in ('md5','sha1','sha256','sha384','sha512'):
...     print str(CRYPT(digest_alg=alg,salt=True)('test')[0])
md5$...$...
sha1$...$...
sha256$...$...
sha384$...$...
sha512$...$...

The syntax is always alg$salt$hash

Supports for pbkdf2

>>> alg = 'pbkdf2(1000,20,sha512)'
>>> print str(CRYPT(digest_alg=alg,salt=True)('test')[0])
pbkdf2(1000,20,sha512)$...$...

An optional hmac_key can be specified and it is used as salt prefix

>>> a = str(CRYPT(digest_alg='md5',key='mykey',salt=True)('test')[0])
>>> print a
md5$...$...

Even if the algorithm changes the hash can still be validated

>>> CRYPT(digest_alg='sha1',key='mykey',salt=True)('test')[0] == a
True

If no salt is specified CRYPT can guess the algorithms from length:

>>> a = str(CRYPT(digest_alg='sha1',salt=False)('test')[0])
>>> a
'sha1$$a94a8fe5ccb19ba61c4c0873d391e987982fbbd3'
>>> CRYPT(digest_alg='sha1',salt=False)('test')[0] == a
True
>>> CRYPT(digest_alg='sha1',salt=False)('test')[0] == a[6:]
True
>>> CRYPT(digest_alg='md5',salt=False)('test')[0] == a
True
>>> CRYPT(digest_alg='md5',salt=False)('test')[0] == a[6:]
True