1 

     2 :mod:`md5` --- MD5 message digest algorithm

     3 ===========================================

     4 

     5 .. module:: md5

     6    :synopsis: RSA's MD5 message digest algorithm.

     7    :deprecated:

     8 

     9 

    10 .. deprecated:: 2.5

    11    Use the :mod:`hashlib` module instead.

    12 

    13 .. index::

    14    single: message digest, MD5

    15    single: checksum; MD5

    16 

    17 This module implements the interface to RSA's MD5 message digest  algorithm (see

    18 also Internet :rfc:`1321`).  Its use is quite straightforward: use :func:`new`

    19 to create an md5 object. You can now feed this object with arbitrary strings

    20 using the :meth:`update` method, and at any point you can ask it for the

    21 :dfn:`digest` (a strong kind of 128-bit checksum, a.k.a. "fingerprint") of the

    22 concatenation of the strings fed to it so far using the :meth:`digest` method.

    23 

    24 For example, to obtain the digest of the string ``'Nobody inspects the spammish

    25 repetition'``:

    26 

    27    >>> import md5

    28    >>> m = md5.new()

    29    >>> m.update("Nobody inspects")

    30    >>> m.update(" the spammish repetition")

    31    >>> m.digest()

    32    '\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'

    33 

    34 More condensed:

    35 

    36    >>> md5.new("Nobody inspects the spammish repetition").digest()

    37    '\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'

    38 

    39 The following values are provided as constants in the module and as attributes

    40 of the md5 objects returned by :func:`new`:

    41 

    42 

    43 .. data:: digest_size

    44 

    45    The size of the resulting digest in bytes.  This is always ``16``.

    46 

    47 The md5 module provides the following functions:

    48 

    49 

    50 .. function:: new([arg])

    51 

    52    Return a new md5 object.  If *arg* is present, the method call ``update(arg)``

    53    is made.

    54 

    55 

    56 .. function:: md5([arg])

    57 

    58    For backward compatibility reasons, this is an alternative name for the

    59    :func:`new` function.

    60 

    61 An md5 object has the following methods:

    62 

    63 

    64 .. method:: md5.update(arg)

    65 

    66    Update the md5 object with the string *arg*.  Repeated calls are equivalent to a

    67    single call with the concatenation of all the arguments: ``m.update(a);

    68    m.update(b)`` is equivalent to ``m.update(a+b)``.

    69 

    70 

    71 .. method:: md5.digest()

    72 

    73    Return the digest of the strings passed to the :meth:`update` method so far.

    74    This is a 16-byte string which may contain non-ASCII characters, including null

    75    bytes.

    76 

    77 

    78 .. method:: md5.hexdigest()

    79 

    80    Like :meth:`digest` except the digest is returned as a string of length 32,

    81    containing only hexadecimal digits.  This may  be used to exchange the value

    82    safely in email or other non-binary environments.

    83 

    84 

    85 .. method:: md5.copy()

    86 

    87    Return a copy ("clone") of the md5 object.  This can be used to efficiently

    88    compute the digests of strings that share a common initial substring.

    89 

    90 

    91 .. seealso::

    92 

    93    Module :mod:`sha`

    94       Similar module implementing the Secure Hash Algorithm (SHA).  The SHA algorithm

    95       is considered a more secure hash.

    96