mirror of https://github.com/python/cpython
92 lines
2.9 KiB
TeX
92 lines
2.9 KiB
TeX
\section{\module{md5} ---
|
|
MD5 message digest algorithm}
|
|
|
|
\declaremodule{builtin}{md5}
|
|
\modulesynopsis{RSA's MD5 message digest algorithm.}
|
|
|
|
|
|
This module implements the interface to RSA's MD5 message digest
|
|
\index{message digest, MD5}
|
|
algorithm (see also Internet \rfc{1321}). Its use is quite
|
|
straightforward:\ use \function{new()} to create an md5 object.
|
|
You can now feed this object with arbitrary strings using the
|
|
\method{update()} method, and at any point you can ask it for the
|
|
\dfn{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 \method{digest()} method.
|
|
\index{checksum!MD5}
|
|
|
|
For example, to obtain the digest of the string \code{'Nobody inspects
|
|
the spammish repetition'}:
|
|
|
|
\begin{verbatim}
|
|
>>> 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'
|
|
\end{verbatim}
|
|
|
|
More condensed:
|
|
|
|
\begin{verbatim}
|
|
>>> md5.new("Nobody inspects the spammish repetition").digest()
|
|
'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'
|
|
\end{verbatim}
|
|
|
|
The following values are provided as constants in the module and as
|
|
attributes of the md5 objects returned by \function{new()}:
|
|
|
|
\begin{datadesc}{digest_size}
|
|
The size of the resulting digest in bytes. This is always
|
|
\code{16}.
|
|
\end{datadesc}
|
|
|
|
md5 objects support the following methods:
|
|
|
|
\begin{funcdesc}{new}{\optional{arg}}
|
|
Return a new md5 object. If \var{arg} is present, the method call
|
|
\code{update(\var{arg})} is made.
|
|
\end{funcdesc}
|
|
|
|
\begin{funcdesc}{md5}{\optional{arg}}
|
|
For backward compatibility reasons, this is an alternative name for the
|
|
\function{new()} function.
|
|
\end{funcdesc}
|
|
|
|
An md5 object has the following methods:
|
|
|
|
\begin{methoddesc}[md5]{update}{arg}
|
|
Update the md5 object with the string \var{arg}. Repeated calls are
|
|
equivalent to a single call with the concatenation of all the
|
|
arguments: \code{m.update(a); m.update(b)} is equivalent to
|
|
\code{m.update(a+b)}.
|
|
\end{methoddesc}
|
|
|
|
\begin{methoddesc}[md5]{digest}{}
|
|
Return the digest of the strings passed to the \method{update()}
|
|
method so far. This is a 16-byte string which may contain
|
|
non-\ASCII{} characters, including null bytes.
|
|
\end{methoddesc}
|
|
|
|
\begin{methoddesc}[md5]{hexdigest}{}
|
|
Like \method{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.
|
|
\end{methoddesc}
|
|
|
|
\begin{methoddesc}[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.
|
|
\end{methoddesc}
|
|
|
|
|
|
\begin{seealso}
|
|
\seemodule{sha}{Similar module implementing the Secure Hash
|
|
Algorithm (SHA). The SHA algorithm is considered a
|
|
more secure hash.}
|
|
\end{seealso}
|