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GeezerVison is showing github.com — python-doc-tw.github.io/library/crypt.html at master · python-doc-tw/python-doc-tw.github.io Expand file tree/ Copy pathcrypt.htmlMore file actions 343 lines (312 loc) · 21.8 KB / Copy pathcrypt.htmlFile metadata and controls343 lines (312 loc) · 21.8 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 <!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" lang="zh_TW"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>36.5. crypt — Function to check Unix passwords — Python 3.7.0 說明文件</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/translations.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="在 Python 3.7.0 說明文件 中搜尋" href="../_static/opensearch.xml"/> <link rel="author" title="關於這些文件" href="../about.html" /> <link rel="index" title="索引" href="../genindex.html" /> <link rel="search" title="搜尋" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="36.6. termios — POSIX style tty control" href="termios.html" /> <link rel="prev" title="36.4. grp — The group database" href="grp.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/library/crypt.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> <script type="text/javascript" src="../_static/switchers.js"></script> </head><body> <div class="related" role="navigation" aria-label="related navigation"> <h3>瀏覽</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" accesskey="I">索引</a></li> <li class="right" > <a href="../py-modindex.html" title="Python 模組索引" >模組</a> |</li> <li class="right" > <a href="termios.html" title="36.6. termios — POSIX style tty control" accesskey="N">下一頁</a> |</li> <li class="right" > <a href="grp.html" title="36.4. grp — The group database" accesskey="P">上一頁</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <span class="language_switcher_placeholder">zh_TW</span> <span class="version_switcher_placeholder">3.7.0</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >Python 標準函式庫 (Standard Library)</a> »</li> <li class="nav-item nav-item-2"><a href="unix.html" accesskey="U">36. Unix Specific Services</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-crypt"> <span id="crypt-function-to-check-unix-passwords"></span><h1>36.5. <a class="reference internal" href="#module-crypt" title="crypt: The crypt() function used to check Unix passwords. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">crypt</span></code></a> — Function to check Unix passwords<a class="headerlink" href="#module-crypt" title="本標題的永久連結">¶</a></h1> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Lib/crypt.py">Lib/crypt.py</a></p> <hr class="docutils" id="index-0" /> <p>This module implements an interface to the <em class="manpage">crypt(3)</em> routine, which is a one-way hash function based upon a modified DES algorithm; see the Unix man page for further details. Possible uses include storing hashed passwords so you can check passwords without storing the actual password, or attempting to crack Unix passwords with a dictionary.</p> <p id="index-1">Notice that the behavior of this module depends on the actual implementation of the <em class="manpage">crypt(3)</em> routine in the running system. Therefore, any extensions available on the current implementation will also be available on this module.</p> <div class="section" id="hashing-methods"> <h2>36.5.1. Hashing Methods<a class="headerlink" href="#hashing-methods" title="本標題的永久連結">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified">3.3 版新加入.</span></p> </div> <p>The <a class="reference internal" href="#module-crypt" title="crypt: The crypt() function used to check Unix passwords. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">crypt</span></code></a> module defines the list of hashing methods (not all methods are available on all platforms):</p> <dl class="data"> <dt id="crypt.METHOD_SHA512"> <code class="descclassname">crypt.</code><code class="descname">METHOD_SHA512</code><a class="headerlink" href="#crypt.METHOD_SHA512" title="本定義的永久連結">¶</a></dt> <dd><p>A Modular Crypt Format method with 16 character salt and 86 character hash based on the SHA-512 hash function. This is the strongest method.</p> </dd></dl> <dl class="data"> <dt id="crypt.METHOD_SHA256"> <code class="descclassname">crypt.</code><code class="descname">METHOD_SHA256</code><a class="headerlink" href="#crypt.METHOD_SHA256" title="本定義的永久連結">¶</a></dt> <dd><p>Another Modular Crypt Format method with 16 character salt and 43 character hash based on the SHA-256 hash function.</p> </dd></dl> <dl class="data"> <dt id="crypt.METHOD_BLOWFISH"> <code class="descclassname">crypt.</code><code class="descname">METHOD_BLOWFISH</code><a class="headerlink" href="#crypt.METHOD_BLOWFISH" title="本定義的永久連結">¶</a></dt> <dd><p>Another Modular Crypt Format method with 22 character salt and 31 character hash based on the Blowfish cipher.</p> <div class="versionadded"> <p><span class="versionmodified">3.7 版新加入.</span></p> </div> </dd></dl> <dl class="data"> <dt id="crypt.METHOD_MD5"> <code class="descclassname">crypt.</code><code class="descname">METHOD_MD5</code><a class="headerlink" href="#crypt.METHOD_MD5" title="本定義的永久連結">¶</a></dt> <dd><p>Another Modular Crypt Format method with 8 character salt and 22 character hash based on the MD5 hash function.</p> </dd></dl> <dl class="data"> <dt id="crypt.METHOD_CRYPT"> <code class="descclassname">crypt.</code><code class="descname">METHOD_CRYPT</code><a class="headerlink" href="#crypt.METHOD_CRYPT" title="本定義的永久連結">¶</a></dt> <dd><p>The traditional method with a 2 character salt and 13 characters of hash. This is the weakest method.</p> </dd></dl> </div> <div class="section" id="module-attributes"> <h2>36.5.2. Module Attributes<a class="headerlink" href="#module-attributes" title="本標題的永久連結">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified">3.3 版新加入.</span></p> </div> <dl class="attribute"> <dt id="crypt.methods"> <code class="descclassname">crypt.</code><code class="descname">methods</code><a class="headerlink" href="#crypt.methods" title="本定義的永久連結">¶</a></dt> <dd><p>A list of available password hashing algorithms, as <code class="docutils literal notranslate"><span class="pre">crypt.METHOD_*</span></code> objects. This list is sorted from strongest to weakest.</p> </dd></dl> </div> <div class="section" id="module-functions"> <h2>36.5.3. Module Functions<a class="headerlink" href="#module-functions" title="本標題的永久連結">¶</a></h2> <p>The <a class="reference internal" href="#module-crypt" title="crypt: The crypt() function used to check Unix passwords. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">crypt</span></code></a> module defines the following functions:</p> <dl class="function"> <dt id="crypt.crypt"> <code class="descclassname">crypt.</code><code class="descname">crypt</code><span class="sig-paren">(</span><em>word</em>, <em>salt=None</em><span class="sig-paren">)</span><a class="headerlink" href="#crypt.crypt" title="本定義的永久連結">¶</a></dt> <dd><p><em>word</em> will usually be a user’s password as typed at a prompt or in a graphical interface. The optional <em>salt</em> is either a string as returned from <a class="reference internal" href="#crypt.mksalt" title="crypt.mksalt"><code class="xref py py-func docutils literal notranslate"><span class="pre">mksalt()</span></code></a>, one of the <code class="docutils literal notranslate"><span class="pre">crypt.METHOD_*</span></code> values (though not all may be available on all platforms), or a full encrypted password including salt, as returned by this function. If <em>salt</em> is not provided, the strongest method will be used (as returned by <a class="reference internal" href="#crypt.methods" title="crypt.methods"><code class="xref py py-func docutils literal notranslate"><span class="pre">methods()</span></code></a>.</p> <p>Checking a password is usually done by passing the plain-text password as <em>word</em> and the full results of a previous <a class="reference internal" href="#module-crypt" title="crypt: The crypt() function used to check Unix passwords. (Unix)"><code class="xref py py-func docutils literal notranslate"><span class="pre">crypt()</span></code></a> call, which should be the same as the results of this call.</p> <p><em>salt</em> (either a random 2 or 16 character string, possibly prefixed with <code class="docutils literal notranslate"><span class="pre">$digit$</span></code> to indicate the method) which will be used to perturb the encryption algorithm. The characters in <em>salt</em> must be in the set <code class="docutils literal notranslate"><span class="pre">[./a-zA-Z0-9]</span></code>, with the exception of Modular Crypt Format which prefixes a <code class="docutils literal notranslate"><span class="pre">$digit$</span></code>.</p> <p>Returns the hashed password as a string, which will be composed of characters from the same alphabet as the salt.</p> <p id="index-2">Since a few <em class="manpage">crypt(3)</em> extensions allow different values, with different sizes in the <em>salt</em>, it is recommended to use the full crypted password as salt when checking for a password.</p> <div class="versionchanged"> <p><span class="versionmodified">3.3 版更變: </span>Accept <code class="docutils literal notranslate"><span class="pre">crypt.METHOD_*</span></code> values in addition to strings for <em>salt</em>.</p> </div> </dd></dl> <dl class="function"> <dt id="crypt.mksalt"> <code class="descclassname">crypt.</code><code class="descname">mksalt</code><span class="sig-paren">(</span><em>method=None</em>, <em>*</em>, <em>rounds=None</em><span class="sig-paren">)</span><a class="headerlink" href="#crypt.mksalt" title="本定義的永久連結">¶</a></dt> <dd><p>Return a randomly generated salt of the specified method. If no <em>method</em> is given, the strongest method available as returned by <a class="reference internal" href="#crypt.methods" title="crypt.methods"><code class="xref py py-func docutils literal notranslate"><span class="pre">methods()</span></code></a> is used.</p> <p>The return value is a string suitable for passing as the <em>salt</em> argument to <a class="reference internal" href="#module-crypt" title="crypt: The crypt() function used to check Unix passwords. (Unix)"><code class="xref py py-func docutils literal notranslate"><span class="pre">crypt()</span></code></a>.</p> <p><em>rounds</em> specifies the number of rounds for <code class="docutils literal notranslate"><span class="pre">METHOD_SHA256</span></code>, <code class="docutils literal notranslate"><span class="pre">METHOD_SHA512</span></code> and <code class="docutils literal notranslate"><span class="pre">METHOD_BLOWFISH</span></code>. For <code class="docutils literal notranslate"><span class="pre">METHOD_SHA256</span></code> and <code class="docutils literal notranslate"><span class="pre">METHOD_SHA512</span></code> it must be an integer between <code class="docutils literal notranslate"><span class="pre">1000</span></code> and <code class="docutils literal notranslate"><span class="pre">999_999_999</span></code>, the default is <code class="docutils literal notranslate"><span class="pre">5000</span></code>. For <code class="docutils literal notranslate"><span class="pre">METHOD_BLOWFISH</span></code> it must be a power of two between <code class="docutils literal notranslate"><span class="pre">16</span></code> (2<sup>4</sup>) and <code class="docutils literal notranslate"><span class="pre">2_147_483_648</span></code> (2<sup>31</sup>), the default is <code class="docutils literal notranslate"><span class="pre">4096</span></code> (2<sup>12</sup>).</p> <div class="versionadded"> <p><span class="versionmodified">3.3 版新加入.</span></p> </div> <div class="versionchanged"> <p><span class="versionmodified">3.7 版更變: </span>Added the <em>rounds</em> parameter.</p> </div> </dd></dl> </div> <div class="section" id="examples"> <h2>36.5.4. Examples<a class="headerlink" href="#examples" title="本標題的永久連結">¶</a></h2> <p>A simple example illustrating typical use (a constant-time comparison operation is needed to limit exposure to timing attacks. <a class="reference internal" href="hmac.html#hmac.compare_digest" title="hmac.compare_digest"><code class="xref py py-func docutils literal notranslate"><span class="pre">hmac.compare_digest()</span></code></a> is suitable for this purpose):</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">pwd</span> <span class="kn">import</span> <span class="nn">crypt</span> <span class="kn">import</span> <span class="nn">getpass</span> <span class="kn">from</span> <span class="nn">hmac</span> <span class="k">import</span> <span class="n">compare_digest</span> <span class="k">as</span> <span class="n">compare_hash</span> <span class="k">def</span> <span class="nf">login</span><span class="p">():</span> <span class="n">username</span> <span class="o">=</span> <span class="nb">input</span><span class="p">(</span><span class="s1">'Python login: '</span><span class="p">)</span> <span class="n">cryptedpasswd</span> <span class="o">=</span> <span class="n">pwd</span><span class="o">.</span><span class="n">getpwnam</span><span class="p">(</span><span class="n">username</span><span class="p">)[</span><span class="mi">1</span><span class="p">]</span> <span class="k">if</span> <span class="n">cryptedpasswd</span><span class="p">:</span> <span class="k">if</span> <span class="n">cryptedpasswd</span> <span class="o">==</span> <span class="s1">'x'</span> <span class="ow">or</span> <span class="n">cryptedpasswd</span> <span class="o">==</span> <span class="s1">'*'</span><span class="p">:</span> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s1">'no support for shadow passwords'</span><span class="p">)</span> <span class="n">cleartext</span> <span class="o">=</span> <span class="n">getpass</span><span class="o">.</span><span class="n">getpass</span><span class="p">()</span> <span class="k">return</span> <span class="n">compare_hash</span><span class="p">(</span><span class="n">crypt</span><span class="o">.</span><span class="n">crypt</span><span class="p">(</span><span class="n">cleartext</span><span class="p">,</span> <span class="n">cryptedpasswd</span><span class="p">),</span> <span class="n">cryptedpasswd</span><span class="p">)</span> <span class="k">else</span><span class="p">:</span> <span class="k">return</span> <span class="kc">True</span> </pre></div> </div> <p>To generate a hash of a password using the strongest available method and check it against the original:</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">crypt</span> <span class="kn">from</span> <span class="nn">hmac</span> <span class="k">import</span> <span class="n">compare_digest</span> <span class="k">as</span> <span class="n">compare_hash</span> <span class="n">hashed</span> <span class="o">=</span> <span class="n">crypt</span><span class="o">.</span><span class="n">crypt</span><span class="p">(</span><span class="n">plaintext</span><span class="p">)</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">compare_hash</span><span class="p">(</span><span class="n">hashed</span><span class="p">,</span> <span class="n">crypt</span><span class="o">.</span><span class="n">crypt</span><span class="p">(</span><span class="n">plaintext</span><span class="p">,</span> <span class="n">hashed</span><span class="p">)):</span> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"hashed version doesn't validate against original"</span><span class="p">)</span> </pre></div> </div> </div> </div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">目錄</a></h3> <ul> <li><a class="reference internal" href="#">36.5. <code class="docutils literal notranslate"><span class="pre">crypt</span></code> — Function to check Unix passwords</a><ul> <li><a class="reference internal" href="#hashing-methods">36.5.1. Hashing Methods</a></li> <li><a class="reference internal" href="#module-attributes">36.5.2. Module Attributes</a></li> <li><a class="reference internal" href="#module-functions">36.5.3. Module Functions</a></li> <li><a class="reference internal" href="#examples">36.5.4. Examples</a></li> </ul> </li> </ul> <h4>上個主題</h4> <p class="topless"><a href="grp.html" title="上一章">36.4. <code class="docutils literal notranslate"><span class="pre">grp</span></code> — The group database</a></p> <h4>下個主題</h4> <p class="topless"><a href="termios.html" title="下一章">36.6. <code class="docutils literal notranslate"><span class="pre">termios</span></code> — POSIX style tty control</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.7/Doc/library/crypt.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="related navigation"> <h3>瀏覽</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >索引</a></li> <li class="right" > <a href="../py-modindex.html" title="Python 模組索引" >模組</a> |</li> <li class="right" > <a href="termios.html" title="36.6. termios — POSIX style tty control" >下一頁</a> |</li> <li class="right" > <a href="grp.html" title="36.4. grp — The group database" >上一頁</a> |</li> <li><img src="../_static/py.png" alt="" style="vertical-align: middle; margin-top: -1px"/></li> <li><a href="https://www.python.org/">Python</a> »</li> <li> <span class="language_switcher_placeholder">zh_TW</span> <span class="version_switcher_placeholder">3.7.0</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >Python 標準函式庫 (Standard Library)</a> »</li> <li class="nav-item nav-item-2"><a href="unix.html" >36. 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