openssl-prebuild/linux_amd64/share/doc/openssl/html/man7/EVP_KDF-PBKDF2.html
2020-03-02 16:50:34 +00:00

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<title>EVP_KDF-PBKDF2</title>
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<li><a href="#name">NAME</a></li>
<li><a href="#description">DESCRIPTION</a></li>
<ul>
<li><a href="#identity">Identity</a></li>
<li><a href="#supported_parameters">Supported parameters</a></li>
</ul>
<li><a href="#notes">NOTES</a></li>
<li><a href="#conforming_to">CONFORMING TO</a></li>
<li><a href="#see_also">SEE ALSO</a></li>
<li><a href="#history">HISTORY</a></li>
<li><a href="#copyright">COPYRIGHT</a></li>
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<h1><a name="name">NAME</a></h1>
<p>EVP_KDF-PBKDF2 - The PBKDF2 EVP_KDF implementation</p>
<p>
</p>
<hr />
<h1><a name="description">DESCRIPTION</a></h1>
<p>Support for computing the <strong>PBKDF2</strong> password-based KDF through the <strong>EVP_KDF</strong>
API.</p>
<p>The EVP_KDF-PBKDF2 algorithm implements the PBKDF2 password-based key
derivation function, as described in SP800-132; it derives a key from a password
using a salt and iteration count.</p>
<p>
</p>
<h2><a name="identity">Identity</a></h2>
<p>&quot;PBKDF2&quot; is the name for this implementation; it
can be used with the <code>EVP_KDF_fetch()</code> function.</p>
<p>
</p>
<h2><a name="supported_parameters">Supported parameters</a></h2>
<p>The supported parameters are:</p>
<dl>
<dt><strong><a name="pass_ossl_kdf_param_password_octet_string" class="item">&quot;pass&quot; (<strong>OSSL_KDF_PARAM_PASSWORD</strong>) &lt;octet string&gt;</a></strong></dt>
<dt><strong><a name="salt_ossl_kdf_param_salt_octet_string" class="item">&quot;salt&quot; (<strong>OSSL_KDF_PARAM_SALT</strong>) &lt;octet string&gt;</a></strong></dt>
<dt><strong><a name="iter_ossl_kdf_param_iter_unsigned_integer" class="item">&quot;iter&quot; (<strong>OSSL_KDF_PARAM_ITER</strong>) &lt;unsigned integer&gt;</a></strong></dt>
<dd>
<p>This parameter has a default value of 2048.</p>
</dd>
<dt><strong><a name="properties_ossl_kdf_param_properties_utf8_string" class="item">&quot;properties&quot; (<strong>OSSL_KDF_PARAM_PROPERTIES</strong>) &lt;UTF8 string&gt;</a></strong></dt>
<dt><strong><a name="digest_ossl_kdf_param_digest_utf8_string" class="item">&quot;digest&quot; (<strong>OSSL_KDF_PARAM_DIGEST</strong>) &lt;UTF8 string&gt;</a></strong></dt>
<dd>
<p>These parameters work as described in <em>EVP_KDF(3)/PARAMETERS</em>.</p>
</dd>
<dt><strong><a name="pkcs5_ossl_kdf_param_pkcs5_integer" class="item">&quot;pkcs5&quot; (<strong>OSSL_KDF_PARAM_PKCS5</strong>) &lt;integer&gt;</a></strong></dt>
<dd>
<p>This parameter can be used to enable or disable SP800-132 compliance checks.
Setting the mode to 0 enables the compliance checks.</p>
<p>The checks performed are:</p>
<dl>
<dt><strong><a name="the_iteration_count_is_at_least_1000" class="item">- the iteration count is at least 1000.</a></strong></dt>
<dt><strong><a name="the_salt_length_is_at_least_128_bits" class="item">- the salt length is at least 128 bits.</a></strong></dt>
<dt><strong><a name="the_derived_key_length_is_at_least_112_bits" class="item">- the derived key length is at least 112 bits.</a></strong></dt>
</dl>
<p>The default provider uses a default mode of 1 for backwards compatibility,
and the fips provider uses a default mode of 0.</p>
<p>The value string is expected to be a decimal number 0 or 1.</p>
</dd>
</dl>
<p>
</p>
<hr />
<h1><a name="notes">NOTES</a></h1>
<p>A typical application of this algorithm is to derive keying material for an
encryption algorithm from a password in the &quot;pass&quot;, a salt in &quot;salt&quot;,
and an iteration count.</p>
<p>Increasing the &quot;iter&quot; parameter slows down the algorithm which makes it
harder for an attacker to perform a brute force attack using a large number
of candidate passwords.</p>
<p>No assumption is made regarding the given password; it is simply treated as a
byte sequence.</p>
<p>
</p>
<hr />
<h1><a name="conforming_to">CONFORMING TO</a></h1>
<p>SP800-132</p>
<p>
</p>
<hr />
<h1><a name="see_also">SEE ALSO</a></h1>
<p><em>EVP_KDF(3)</em>,
<em>EVP_KDF_CTX_new(3)</em>,
<em>EVP_KDF_CTX_free(3)</em>,
<em>EVP_KDF_CTX_set_params(3)</em>,
<em>EVP_KDF_derive(3)</em>,
<em>EVP_KDF(3)/PARAMETERS</em></p>
<p>
</p>
<hr />
<h1><a name="history">HISTORY</a></h1>
<p>This functionality was added to OpenSSL 3.0.</p>
<p>
</p>
<hr />
<h1><a name="copyright">COPYRIGHT</a></h1>
<p>Copyright 2018-2019 The OpenSSL Project Authors. All Rights Reserved.</p>
<p>Licensed under the Apache License 2.0 (the &quot;License&quot;). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>
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