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\section{\module{md5} --- MD5 message digest algorithm} \declaremodule{builtin}{md5} \modulesynopsis{RSA's MD5 message digest algorithm.} \deprecated{2.5}{Use the \refmodule{hashlib} module instead.} 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} The md5 module provides the following functions: \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}