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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">base64</span></code> — Base16, Base32, Base64, Base85 Data Encodings</a><ul>
<li><a class="reference internal" href="#rfc-4648-encodings">RFC 4648 Encodings</a></li>
<li><a class="reference internal" href="#base85-encodings">Base85 Encodings</a></li>
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  <section id="module-base64">
<span id="base64-base16-base32-base64-base85-data-encodings"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">base64</span></code> — Base16, Base32, Base64, Base85 Data Encodings<a class="headerlink" href="#module-base64" title="Link to this heading">¶</a></h1>
<p><strong>Source code:</strong> <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/main/Lib/base64.py">Lib/base64.py</a></p>
<hr class="docutils" id="index-0" />
<p>This module provides functions for encoding binary data to printable
ASCII characters and decoding such encodings back to binary data.
This includes the <a class="reference internal" href="#base64-rfc-4648"><span class="std std-ref">encodings specified in</span></a>
<span class="target" id="index-1"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a> (Base64, Base32 and Base16)
and the non-standard <a class="reference internal" href="#base64-base-85"><span class="std std-ref">Base85 encodings</span></a>.</p>
<p>There are two interfaces provided by this module.  The modern interface
supports encoding <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like objects</span></a> to ASCII
<a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>, and decoding <span class="xref std std-term">bytes-like objects</span> or
strings containing ASCII to <code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code>.  Both base-64 alphabets
defined in <span class="target" id="index-2"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a> (normal, and URL- and filesystem-safe) are supported.</p>
<p>The <a class="reference internal" href="#base64-legacy"><span class="std std-ref">legacy interface</span></a> does not support decoding from strings, but it does
provide functions for encoding and decoding to and from <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file objects</span></a>.  It only supports the Base64 standard alphabet, and it adds
newlines every 76 characters as per <span class="target" id="index-3"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc2045.html"><strong>RFC 2045</strong></a>.  Note that if you are looking
for <span class="target" id="index-4"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc2045.html"><strong>RFC 2045</strong></a> support you probably want to be looking at the <a class="reference internal" href="email.html#module-email" title="email: Package supporting the parsing, manipulating, and generating email messages."><code class="xref py py-mod docutils literal notranslate"><span class="pre">email</span></code></a>
package instead.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.3: </span>ASCII-only Unicode strings are now accepted by the decoding functions of
the modern interface.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.4: </span>Any <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like objects</span></a> are now accepted by all
encoding and decoding functions in this module.  Ascii85/Base85 support added.</p>
</div>
<section id="rfc-4648-encodings">
<span id="base64-rfc-4648"></span><h2>RFC 4648 Encodings<a class="headerlink" href="#rfc-4648-encodings" title="Link to this heading">¶</a></h2>
<p>The <span class="target" id="index-5"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a> encodings are suitable for encoding binary data so that it can be
safely sent by email, used as parts of URLs, or included as part of an HTTP
POST request.</p>
<dl class="py function">
<dt class="sig sig-object py" id="base64.b64encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b64encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">altchars</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">wrapcol</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b64encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em> using Base64 and return the encoded
<a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p>Optional <em>altchars</em> must be a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> of length 2 which
specifies an alternative alphabet for the <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">/</span></code> characters.
This allows an application to e.g. generate URL or filesystem safe Base64
strings.  The default is <code class="docutils literal notranslate"><span class="pre">None</span></code>, for which the standard Base64 alphabet is used.</p>
<p>If <em>wrapcol</em> is non-zero, insert a newline (<code class="docutils literal notranslate"><span class="pre">b'\n'</span></code>) character
after at most every <em>wrapcol</em> characters.
If <em>wrapcol</em> is zero (default), do not insert any newlines.</p>
<p>May assert or raise a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if the length of <em>altchars</em> is not 2.  Raises a
<a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TypeError</span></code></a> if <em>altchars</em> is not a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.15: </span>Added the <em>wrapcol</em> parameter.</p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b64decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b64decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">altchars</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">validate</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b64decode" title="Link to this definition">¶</a></dt>
<dt class="sig sig-object py">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b64decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">altchars</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">validate</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">True</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">ignorechars</span></span></em><span class="sig-paren">)</span></dt>
<dd><p>Decode the Base64 encoded <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string
<em>s</em> and return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p>Optional <em>altchars</em> must be a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string
of length 2 which specifies the alternative alphabet used instead of the
<code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">/</span></code> characters.</p>
<p>A <a class="reference internal" href="binascii.html#binascii.Error" title="binascii.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">binascii.Error</span></code></a> exception is raised
if <em>s</em> is incorrectly padded.</p>
<p>If <em>ignorechars</em> is specified, it should be a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a>
containing characters to ignore from the input when <em>validate</em> is true.
If <em>ignorechars</em> contains the pad character <code class="docutils literal notranslate"><span class="pre">'='</span></code>,  the pad characters
presented before the end of the encoded data and the excess pad characters
will be ignored.
The default value of <em>validate</em> is <code class="docutils literal notranslate"><span class="pre">True</span></code> if <em>ignorechars</em> is specified,
<code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise.</p>
<p>If <em>validate</em> is false, characters that are neither
in the normal base-64 alphabet nor (if <em>ignorechars</em> is not specified)
the alternative alphabet are
discarded prior to the padding check, but the <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">/</span></code> characters
keep their meaning if they are not in <em>altchars</em> (they will be discarded
in future Python versions).</p>
<p>If <em>validate</em> is true, these non-alphabet characters in the input
result in a <a class="reference internal" href="binascii.html#binascii.Error" title="binascii.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">binascii.Error</span></code></a>.</p>
<p>For more information about the strict base64 check, see <a class="reference internal" href="binascii.html#binascii.a2b_base64" title="binascii.a2b_base64"><code class="xref py py-func docutils literal notranslate"><span class="pre">binascii.a2b_base64()</span></code></a></p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.15: </span>Added the <em>ignorechars</em> parameter.</p>
</div>
<div class="deprecated">
<p><span class="versionmodified deprecated">Deprecated since version 3.15: </span>Accepting the <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">/</span></code> characters with an alternative alphabet
is now deprecated.</p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.standard_b64encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">standard_b64encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.standard_b64encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em> using the standard Base64 alphabet
and return the encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.standard_b64decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">standard_b64decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.standard_b64decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>s</em> using the standard
Base64 alphabet and return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.urlsafe_b64encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">urlsafe_b64encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.urlsafe_b64encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em> using the
URL- and filesystem-safe alphabet, which
substitutes <code class="docutils literal notranslate"><span class="pre">-</span></code> instead of <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">_</span></code> instead of <code class="docutils literal notranslate"><span class="pre">/</span></code> in the
standard Base64 alphabet, and return the encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.  The result
can still contain <code class="docutils literal notranslate"><span class="pre">=</span></code>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.urlsafe_b64decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">urlsafe_b64decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.urlsafe_b64decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>s</em>
using the URL- and filesystem-safe
alphabet, which substitutes <code class="docutils literal notranslate"><span class="pre">-</span></code> instead of <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">_</span></code> instead of
<code class="docutils literal notranslate"><span class="pre">/</span></code> in the standard Base64 alphabet, and return the decoded
<a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<div class="deprecated">
<p><span class="versionmodified deprecated">Deprecated since version 3.15: </span>Accepting the <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">/</span></code> characters is now deprecated.</p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b32encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b32encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b32encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em> using Base32 and return the
encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b32decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b32decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">casefold</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">map01</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b32decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode the Base32 encoded <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>s</em> and
return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p>Optional <em>casefold</em> is a flag specifying
whether a lowercase alphabet is acceptable as input.  For security purposes,
the default is <code class="docutils literal notranslate"><span class="pre">False</span></code>.</p>
<p><span class="target" id="index-6"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a> allows for optional mapping of the digit 0 (zero) to the letter O
(oh), and for optional mapping of the digit 1 (one) to either the letter I (eye)
or letter L (el).  The optional argument <em>map01</em> when not <code class="docutils literal notranslate"><span class="pre">None</span></code>, specifies
which letter the digit 1 should be mapped to (when <em>map01</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, the
digit 0 is always mapped to the letter O).  For security purposes the default is
<code class="docutils literal notranslate"><span class="pre">None</span></code>, so that 0 and 1 are not allowed in the input.</p>
<p>A <a class="reference internal" href="binascii.html#binascii.Error" title="binascii.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">binascii.Error</span></code></a> is raised if <em>s</em> is
incorrectly padded or if there are non-alphabet characters present in the
input.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b32hexencode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b32hexencode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b32hexencode" title="Link to this definition">¶</a></dt>
<dd><p>Similar to <a class="reference internal" href="#base64.b32encode" title="base64.b32encode"><code class="xref py py-func docutils literal notranslate"><span class="pre">b32encode()</span></code></a> but uses the Extended Hex Alphabet, as defined in
<span class="target" id="index-7"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a>.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.10.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b32hexdecode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b32hexdecode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">casefold</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b32hexdecode" title="Link to this definition">¶</a></dt>
<dd><p>Similar to <a class="reference internal" href="#base64.b32decode" title="base64.b32decode"><code class="xref py py-func docutils literal notranslate"><span class="pre">b32decode()</span></code></a> but uses the Extended Hex Alphabet, as defined in
<span class="target" id="index-8"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a>.</p>
<p>This version does not allow the digit 0 (zero) to the letter O (oh) and digit
1 (one) to either the letter I (eye) or letter L (el) mappings, all these
characters are included in the Extended Hex Alphabet and are not
interchangeable.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.10.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b16encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b16encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b16encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em> using Base16 and return the
encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b16decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b16decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">casefold</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b16decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode the Base16 encoded <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>s</em> and
return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p>Optional <em>casefold</em> is a flag specifying whether a
lowercase alphabet is acceptable as input.  For security purposes, the default
is <code class="docutils literal notranslate"><span class="pre">False</span></code>.</p>
<p>A <a class="reference internal" href="binascii.html#binascii.Error" title="binascii.Error"><code class="xref py py-exc docutils literal notranslate"><span class="pre">binascii.Error</span></code></a> is raised if <em>s</em> is
incorrectly padded or if there are non-alphabet characters present in the
input.</p>
</dd></dl>

</section>
<section id="base85-encodings">
<span id="base64-base-85"></span><h2>Base85 Encodings<a class="headerlink" href="#base85-encodings" title="Link to this heading">¶</a></h2>
<p>Base85 encoding is not formally specified but rather a de facto standard,
thus different systems perform the encoding differently.</p>
<p>The <a class="reference internal" href="#base64.a85encode" title="base64.a85encode"><code class="xref py py-func docutils literal notranslate"><span class="pre">a85encode()</span></code></a> and <a class="reference internal" href="#base64.b85encode" title="base64.b85encode"><code class="xref py py-func docutils literal notranslate"><span class="pre">b85encode()</span></code></a> functions in this module are two implementations of
the de facto standard. You should call the function with the Base85
implementation used by the software you intend to work with.</p>
<p>The two functions present in this module differ in how they handle the following:</p>
<ul class="simple">
<li><p>Whether to include enclosing <code class="docutils literal notranslate"><span class="pre">&lt;~</span></code> and <code class="docutils literal notranslate"><span class="pre">~&gt;</span></code> markers</p></li>
<li><p>Whether to include newline characters</p></li>
<li><p>The set of ASCII characters used for encoding</p></li>
<li><p>Handling of null bytes</p></li>
</ul>
<p>Refer to the documentation of the individual functions for more information.</p>
<dl class="py function">
<dt class="sig sig-object py" id="base64.a85encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">a85encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">b</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">foldspaces</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">wrapcol</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">pad</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">adobe</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.a85encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>b</em> using Ascii85 and return the
encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p><em>foldspaces</em> is an optional flag that uses the special short sequence ‘y’
instead of 4 consecutive spaces (ASCII 0x20) as supported by ‘btoa’. This
feature is not supported by the “standard” Ascii85 encoding.</p>
<p>If <em>wrapcol</em> is non-zero, insert a newline (<code class="docutils literal notranslate"><span class="pre">b'\n'</span></code>) character
after at most every <em>wrapcol</em> characters.
If <em>wrapcol</em> is zero (default), do not insert any newlines.</p>
<p>If <em>pad</em> is true, the input is padded with <code class="docutils literal notranslate"><span class="pre">b'\0'</span></code> so its length is a
multiple of 4 bytes before encoding.
Note that the <code class="docutils literal notranslate"><span class="pre">btoa</span></code> implementation always pads.</p>
<p><em>adobe</em> controls whether the encoded byte sequence is framed with <code class="docutils literal notranslate"><span class="pre">&lt;~</span></code>
and <code class="docutils literal notranslate"><span class="pre">~&gt;</span></code>, which is used by the Adobe implementation.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.4.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.a85decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">a85decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">b</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">foldspaces</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">adobe</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ignorechars</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">b'</span> <span class="pre">\t\n\r\x0b'</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.a85decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode the Ascii85 encoded <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>b</em> and
return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p><em>foldspaces</em> is a flag that specifies whether the ‘y’ short sequence
should be accepted as shorthand for 4 consecutive spaces (ASCII 0x20).
This feature is not supported by the “standard” Ascii85 encoding.</p>
<p><em>adobe</em> controls whether the input sequence is in Adobe Ascii85 format
(i.e. is framed with &lt;~ and ~&gt;).</p>
<p><em>ignorechars</em> should be a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> containing characters
to ignore from the input.
This should only contain whitespace characters, and by
default contains all whitespace characters in ASCII.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.4.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b85encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b85encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">b</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">pad</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b85encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>b</em> using base85 (as used in e.g.
git-style binary diffs) and return the encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<p>If <em>pad</em> is true, the input is padded with <code class="docutils literal notranslate"><span class="pre">b'\0'</span></code> so its length is a
multiple of 4 bytes before encoding.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.4.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.b85decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">b85decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">b</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.b85decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode the base85-encoded <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>b</em> and
return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.  Padding is implicitly removed, if
necessary.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.4.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.z85encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">z85encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">pad</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.z85encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em> using Z85 (as used in ZeroMQ)
and return the encoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.  See <a class="reference external" href="https://rfc.zeromq.org/spec/32/">Z85  specification</a> for more information.</p>
<p>If <em>pad</em> is true, the input is padded with <code class="docutils literal notranslate"><span class="pre">b'\0'</span></code> so its length is a
multiple of 4 bytes before encoding.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.13.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.15: </span>The <em>pad</em> parameter was added.</p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.z85decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">z85decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.z85decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode the Z85-encoded <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> or ASCII string <em>s</em> and
return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.  See <a class="reference external" href="https://rfc.zeromq.org/spec/32/">Z85  specification</a> for more information.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.13.</span></p>
</div>
</dd></dl>

</section>
<section id="legacy-interface">
<span id="base64-legacy"></span><h2>Legacy Interface<a class="headerlink" href="#legacy-interface" title="Link to this heading">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="base64.decode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">decode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">input</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">output</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.decode" title="Link to this definition">¶</a></dt>
<dd><p>Decode the contents of the binary <em>input</em> file and write the resulting binary
data to the <em>output</em> file. <em>input</em> and <em>output</em> must be <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file objects</span></a>. <em>input</em> will be read until <code class="docutils literal notranslate"><span class="pre">input.readline()</span></code> returns an
empty bytes object.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.decodebytes">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">decodebytes</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.decodebytes" title="Link to this definition">¶</a></dt>
<dd><p>Decode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em>, which must contain one or more
lines of base64 encoded data, and return the decoded <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a>.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.1.</span></p>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.encode">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">encode</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">input</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">output</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.encode" title="Link to this definition">¶</a></dt>
<dd><p>Encode the contents of the binary <em>input</em> file and write the resulting base64
encoded data to the <em>output</em> file. <em>input</em> and <em>output</em> must be <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file
objects</span></a>. <em>input</em> will be read until <code class="docutils literal notranslate"><span class="pre">input.read()</span></code> returns
an empty bytes object. <code class="xref py py-func docutils literal notranslate"><span class="pre">encode()</span></code> inserts a newline character (<code class="docutils literal notranslate"><span class="pre">b'\n'</span></code>)
after every 76 bytes of the output, as well as ensuring that the output
always ends with a newline, as per <span class="target" id="index-9"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc2045.html"><strong>RFC 2045</strong></a> (MIME).</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="base64.encodebytes">
<span class="sig-prename descclassname"><span class="pre">base64.</span></span><span class="sig-name descname"><span class="pre">encodebytes</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#base64.encodebytes" title="Link to this definition">¶</a></dt>
<dd><p>Encode the <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> <em>s</em>, which can contain arbitrary binary
data, and return <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> containing the base64-encoded data, with newlines
(<code class="docutils literal notranslate"><span class="pre">b'\n'</span></code>) inserted after every 76 bytes of output, and ensuring that
there is a trailing newline, as per <span class="target" id="index-10"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc2045.html"><strong>RFC 2045</strong></a> (MIME).</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.1.</span></p>
</div>
</dd></dl>

<p>An example usage of the module:</p>
<div class="doctest highlight-default notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="kn">import</span><span class="w"> </span><span class="nn">base64</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">encoded</span> <span class="o">=</span> <span class="n">base64</span><span class="o">.</span><span class="n">b64encode</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;data to be encoded&#39;</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">encoded</span>
<span class="go">b&#39;ZGF0YSB0byBiZSBlbmNvZGVk&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">data</span> <span class="o">=</span> <span class="n">base64</span><span class="o">.</span><span class="n">b64decode</span><span class="p">(</span><span class="n">encoded</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">data</span>
<span class="go">b&#39;data to be encoded&#39;</span>
</pre></div>
</div>
</section>
<section id="security-considerations">
<span id="base64-security"></span><h2>Security Considerations<a class="headerlink" href="#security-considerations" title="Link to this heading">¶</a></h2>
<p>A new security considerations section was added to <span class="target" id="index-11"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc4648.html"><strong>RFC 4648</strong></a> (section 12); it’s
recommended to review the security section for any code deployed to production.</p>
<div class="admonition seealso">
<p class="admonition-title">See also</p>
<dl class="simple">
<dt>Module <a class="reference internal" href="binascii.html#module-binascii" title="binascii: Tools for converting between binary and various ASCII-encoded binary representations."><code class="xref py py-mod docutils literal notranslate"><span class="pre">binascii</span></code></a></dt><dd><p>Support module containing ASCII-to-binary and binary-to-ASCII conversions.</p>
</dd>
<dt><span class="target" id="index-12"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc1521.html"><strong>RFC 1521</strong></a> - MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies</dt><dd><p>Section 5.2, “Base64 Content-Transfer-Encoding,” provides the definition of the
base64 encoding.</p>
</dd>
</dl>
</div>
</section>
</section>


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