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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>14.3. md5 — MD5 message digest algorithm — Python v2.6.6 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '2.6.6', COLLAPSE_MODINDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python v2.6.6 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="top" title="Python v2.6.6 documentation" href="../index.html" /> <link rel="up" title="14. 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Cryptographic Services</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="module-md5"> <h1>14.3. <tt class="xref docutils literal"><span class="pre">md5</span></tt> — MD5 message digest algorithm<a class="headerlink" href="#module-md5" title="Permalink to this headline">¶</a></h1> <p class="deprecated"> <span class="versionmodified">Deprecated since version 2.5: </span>Use the <a title="Secure hash and message digest algorithms." class="reference external" href="hashlib.html#module-hashlib"><tt class="xref docutils literal"><span class="pre">hashlib</span></tt></a> module instead.</p> <p id="index-430">This module implements the interface to RSA’s MD5 message digest algorithm (see also Internet <span class="target" id="index-431"></span><a class="reference external" href="http://tools.ietf.org/html/rfc1321.html"><strong>RFC 1321</strong></a>). Its use is quite straightforward: use <a title="md5.new" class="reference internal" href="#md5.new"><tt class="xref docutils literal"><span class="pre">new()</span></tt></a> to create an md5 object. You can now feed this object with arbitrary strings using the <tt class="xref docutils literal"><span class="pre">update()</span></tt> method, and at any point you can ask it for the <em>digest</em> (a strong kind of 128-bit checksum, a.k.a. “fingerprint”) of the concatenation of the strings fed to it so far using the <tt class="xref docutils literal"><span class="pre">digest()</span></tt> method.</p> <p>For example, to obtain the digest of the string <tt class="docutils literal"><span class="pre">'Nobody</span> <span class="pre">inspects</span> <span class="pre">the</span> <span class="pre">spammish</span> <span class="pre">repetition'</span></tt>:</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">md5</span> <span class="gp">>>> </span><span class="n">m</span> <span class="o">=</span> <span class="n">md5</span><span class="o">.</span><span class="n">new</span><span class="p">()</span> <span class="gp">>>> </span><span class="n">m</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="s">"Nobody inspects"</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">m</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="s">" the spammish repetition"</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">m</span><span class="o">.</span><span class="n">digest</span><span class="p">()</span> <span class="go">'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'</span> </pre></div> </div> <p>More condensed:</p> <div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="n">md5</span><span class="o">.</span><span class="n">new</span><span class="p">(</span><span class="s">"Nobody inspects the spammish repetition"</span><span class="p">)</span><span class="o">.</span><span class="n">digest</span><span class="p">()</span> <span class="go">'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'</span> </pre></div> </div> <p>The following values are provided as constants in the module and as attributes of the md5 objects returned by <a title="md5.new" class="reference internal" href="#md5.new"><tt class="xref docutils literal"><span class="pre">new()</span></tt></a>:</p> <dl class="data"> <dt id="md5.digest_size"> <tt class="descclassname">md5.</tt><tt class="descname">digest_size</tt><a class="headerlink" href="#md5.digest_size" title="Permalink to this definition">¶</a></dt> <dd>The size of the resulting digest in bytes. This is always <tt class="docutils literal"><span class="pre">16</span></tt>.</dd></dl> <p>The md5 module provides the following functions:</p> <dl class="function"> <dt id="md5.new"> <tt class="descclassname">md5.</tt><tt class="descname">new</tt><big>(</big><span class="optional">[</span><em>arg</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#md5.new" title="Permalink to this definition">¶</a></dt> <dd>Return a new md5 object. If <em>arg</em> is present, the method call <tt class="docutils literal"><span class="pre">update(arg)</span></tt> is made.</dd></dl> <dl class="function"> <dt id="md5.md5"> <tt class="descclassname">md5.</tt><tt class="descname">md5</tt><big>(</big><span class="optional">[</span><em>arg</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#md5.md5" title="Permalink to this definition">¶</a></dt> <dd>For backward compatibility reasons, this is an alternative name for the <a title="md5.new" class="reference internal" href="#md5.new"><tt class="xref docutils literal"><span class="pre">new()</span></tt></a> function.</dd></dl> <p>An md5 object has the following methods:</p> <dl class="method"> <dt id="md5.md5.update"> <tt class="descclassname">md5.</tt><tt class="descname">update</tt><big>(</big><em>arg</em><big>)</big><a class="headerlink" href="#md5.md5.update" title="Permalink to this definition">¶</a></dt> <dd>Update the md5 object with the string <em>arg</em>. Repeated calls are equivalent to a single call with the concatenation of all the arguments: <tt class="docutils literal"><span class="pre">m.update(a);</span> <span class="pre">m.update(b)</span></tt> is equivalent to <tt class="docutils literal"><span class="pre">m.update(a+b)</span></tt>.</dd></dl> <dl class="method"> <dt id="md5.md5.digest"> <tt class="descclassname">md5.</tt><tt class="descname">digest</tt><big>(</big><big>)</big><a class="headerlink" href="#md5.md5.digest" title="Permalink to this definition">¶</a></dt> <dd>Return the digest of the strings passed to the <a title="md5.md5.update" class="reference internal" href="#md5.md5.update"><tt class="xref docutils literal"><span class="pre">update()</span></tt></a> method so far. This is a 16-byte string which may contain non-ASCII characters, including null bytes.</dd></dl> <dl class="method"> <dt id="md5.md5.hexdigest"> <tt class="descclassname">md5.</tt><tt class="descname">hexdigest</tt><big>(</big><big>)</big><a class="headerlink" href="#md5.md5.hexdigest" title="Permalink to this definition">¶</a></dt> <dd>Like <a title="md5.md5.digest" class="reference internal" href="#md5.md5.digest"><tt class="xref docutils literal"><span class="pre">digest()</span></tt></a> 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.</dd></dl> <dl class="method"> <dt id="md5.md5.copy"> <tt class="descclassname">md5.</tt><tt class="descname">copy</tt><big>(</big><big>)</big><a class="headerlink" href="#md5.md5.copy" title="Permalink to this definition">¶</a></dt> <dd>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.</dd></dl> <div class="admonition-see-also admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <dt>Module <a title="NIST's secure hash algorithm, SHA. (deprecated)" class="reference external" href="sha.html#module-sha"><tt class="xref docutils literal"><span class="pre">sha</span></tt></a></dt> <dd>Similar module implementing the Secure Hash Algorithm (SHA). 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