14.3. "md5" — MD5 message digest algorithm
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2.5 版後已棄用: Use the "hashlib" module instead.

This module implements the interface to RSA’s MD5 message digest
algorithm (see also Internet **RFC 1321**).  Its use is quite
straightforward: use "new()" to create an md5 object. You can now feed
this object with arbitrary strings using the "update()" method, and at
any point you can ask it for the *digest* (a strong kind of 128-bit
checksum, a.k.a. 「fingerprint」) of the concatenation of the strings
fed to it so far using the "digest()" method.

For example, to obtain the digest of the string "'Nobody inspects the
spammish repetition'":

>>> import md5
>>> m = md5.new()
>>> m.update("Nobody inspects")
>>> m.update(" the spammish repetition")
>>> m.digest()
'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'

More condensed:

>>> md5.new("Nobody inspects the spammish repetition").digest()
'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'

The following values are provided as constants in the module and as
attributes of the md5 objects returned by "new()":

md5.digest_size

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

The md5 module provides the following functions:

md5.new([arg])

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

md5.md5([arg])

   For backward compatibility reasons, this is an alternative name for
   the "new()" function.

An md5 object has the following methods:

md5.update(arg)

   Update the md5 object with the string *arg*.  Repeated calls are
   equivalent to a single call with the concatenation of all the
   arguments: "m.update(a); m.update(b)" is equivalent to
   "m.update(a+b)".

md5.digest()

   Return the digest of the strings passed to the "update()" method so
   far. This is a 16-byte string which may contain non-ASCII
   characters, including null bytes.

md5.hexdigest()

   Like "digest()" except the digest is returned as a string of length
   32, containing only hexadecimal digits.  This may  be used to
   exchange the value safely in email or other non-binary
   environments.

md5.copy()

   Return a copy (「clone」) of the md5 object.  This can be used to
   efficiently compute the digests of strings that share a common
   initial substring.

也參考:

  Module "sha"
     Similar module implementing the Secure Hash Algorithm (SHA).  The
     SHA algorithm is considered a more secure hash.
