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<?xml version="1.0" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>PKCS5_PBKDF2_HMAC</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <link rev="made" href="mailto:root@hsxx.drive.ne.jp" /> </head> <body style="background-color: white"> <!-- INDEX BEGIN --> <div name="index"> <p><a name="__index__"></a></p> <ul> <li><a href="#name">NAME</a></li> <li><a href="#synopsis">SYNOPSIS</a></li> <li><a href="#description">DESCRIPTION</a></li> <li><a href="#notes">NOTES</a></li> <li><a href="#return_values">RETURN VALUES</a></li> <li><a href="#see_also">SEE ALSO</a></li> <li><a href="#copyright">COPYRIGHT</a></li> </ul> <hr name="index" /> </div> <!-- INDEX END --> <p> </p> <hr /> <h1><a name="name">NAME</a></h1> <p>PKCS5_PBKDF2_HMAC, PKCS5_PBKDF2_HMAC_SHA1 - password based derivation routines with salt and iteration count</p> <p> </p> <hr /> <h1><a name="synopsis">SYNOPSIS</a></h1> <pre> #include <openssl/evp.h></pre> <pre> int PKCS5_PBKDF2_HMAC(const char *pass, int passlen, const unsigned char *salt, int saltlen, int iter, const EVP_MD *digest, int keylen, unsigned char *out);</pre> <pre> int PKCS5_PBKDF2_HMAC_SHA1(const char *pass, int passlen, const unsigned char *salt, int saltlen, int iter, int keylen, unsigned char *out);</pre> <p> </p> <hr /> <h1><a name="description">DESCRIPTION</a></h1> <p>PKCS5_PBKDF2_HMAC() derives a key from a password using a salt and iteration count as specified in <a href="http://www.ietf.org/rfc/rfc2898.txt" class="rfc">RFC 2898</a>.</p> <p><strong>pass</strong> is the password used in the derivation of length <strong>passlen</strong>. <strong>pass</strong> is an optional parameter and can be NULL. If <strong>passlen</strong> is -1, then the function will calculate the length of <strong>pass</strong> using <code>strlen()</code>.</p> <p><strong>salt</strong> is the salt used in the derivation of length <strong>saltlen</strong>. If the <strong>salt</strong> is NULL, then <strong>saltlen</strong> must be 0. The function will not attempt to calculate the length of the <strong>salt</strong> because it is not assumed to be NULL terminated.</p> <p><strong>iter</strong> is the iteration count and its value should be greater than or equal to 1. <a href="http://www.ietf.org/rfc/rfc2898.txt" class="rfc">RFC 2898</a> suggests an iteration count of at least 1000. Any <strong>iter</strong> less than 1 is treated as a single iteration.</p> <p><strong>digest</strong> is the message digest function used in the derivation. Values include any of the EVP_* message digests. PKCS5_PBKDF2_HMAC_SHA1() calls PKCS5_PBKDF2_HMAC() with EVP_sha1().</p> <p>The derived key will be written to <strong>out</strong>. The size of the <strong>out</strong> buffer is specified via <strong>keylen</strong>.</p> <p> </p> <hr /> <h1><a name="notes">NOTES</a></h1> <p>A typical application of this function is to derive keying material for an encryption algorithm from a password in the <strong>pass</strong>, a salt in <strong>salt</strong>, and an iteration count.</p> <p>Increasing the <strong>iter</strong> 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>These functions make no assumption regarding the given password. It will simply be treated as a byte sequence.</p> <p> </p> <hr /> <h1><a name="return_values">RETURN VALUES</a></h1> <p>PKCS5_PBKDF2_HMAC() and PBKCS5_PBKDF2_HMAC_SHA1() return 1 on success or 0 on error.</p> <p> </p> <hr /> <h1><a name="see_also">SEE ALSO</a></h1> <p><em>evp(7)</em>, <em>RAND_bytes(3)</em>, <em>EVP_BytesToKey(3)</em>, <em>passphrase-encoding(7)</em></p> <p> </p> <hr /> <h1><a name="copyright">COPYRIGHT</a></h1> <p>Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved.</p> <p>Licensed under the OpenSSL license (the "License"). 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> </body> </html>