<?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>EVP_RAND-HMAC-DRBG</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<link rev="made" href="mailto:root@localhost" />
</head>
<body>
<ul id="index">
<li><a href="#NAME">NAME</a></li>
<li><a href="#DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#Identity">Identity</a></li>
<li><a href="#Supported-parameters">Supported parameters</a></li>
</ul>
</li>
<li><a href="#NOTES">NOTES</a></li>
<li><a href="#EXAMPLES">EXAMPLES</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>
</ul>
<h1 id="NAME">NAME</h1>
<p>EVP_RAND-HMAC-DRBG - The HMAC DRBG EVP_RAND implementation</p>
<h1 id="DESCRIPTION">DESCRIPTION</h1>
<p>Support for the HMAC deterministic random bit generator through the <b>EVP_RAND</b> API.</p>
<h2 id="Identity">Identity</h2>
<p>"HMAC-DRBG" is the name for this implementation; it can be used with the EVP_RAND_fetch() function.</p>
<h2 id="Supported-parameters">Supported parameters</h2>
<p>The supported parameters are:</p>
<dl>
<dt id="state-OSSL_RAND_PARAM_STATE-integer">"state" (<b>OSSL_RAND_PARAM_STATE</b>) <integer></dt>
<dd>
</dd>
<dt id="strength-OSSL_RAND_PARAM_STRENGTH-unsigned-integer">"strength" (<b>OSSL_RAND_PARAM_STRENGTH</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="max_request-OSSL_RAND_PARAM_MAX_REQUEST-unsigned-integer">"max_request" (<b>OSSL_RAND_PARAM_MAX_REQUEST</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="reseed_requests-OSSL_DRBG_PARAM_RESEED_REQUESTS-unsigned-integer">"reseed_requests" (<b>OSSL_DRBG_PARAM_RESEED_REQUESTS</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="reseed_time_interval-OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL-integer">"reseed_time_interval" (<b>OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL</b>) <integer></dt>
<dd>
</dd>
<dt id="min_entropylen-OSSL_DRBG_PARAM_MIN_ENTROPYLEN-unsigned-integer">"min_entropylen" (<b>OSSL_DRBG_PARAM_MIN_ENTROPYLEN</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="max_entropylen-OSSL_DRBG_PARAM_MAX_ENTROPYLEN-unsigned-integer">"max_entropylen" (<b>OSSL_DRBG_PARAM_MAX_ENTROPYLEN</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="min_noncelen-OSSL_DRBG_PARAM_MIN_NONCELEN-unsigned-integer">"min_noncelen" (<b>OSSL_DRBG_PARAM_MIN_NONCELEN</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="max_noncelen-OSSL_DRBG_PARAM_MAX_NONCELEN-unsigned-integer">"max_noncelen" (<b>OSSL_DRBG_PARAM_MAX_NONCELEN</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="max_perslen-OSSL_DRBG_PARAM_MAX_PERSLEN-unsigned-integer">"max_perslen" (<b>OSSL_DRBG_PARAM_MAX_PERSLEN</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="max_adinlen-OSSL_DRBG_PARAM_MAX_ADINLEN-unsigned-integer">"max_adinlen" (<b>OSSL_DRBG_PARAM_MAX_ADINLEN</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="reseed_counter-OSSL_DRBG_PARAM_RESEED_COUNTER-unsigned-integer">"reseed_counter" (<b>OSSL_DRBG_PARAM_RESEED_COUNTER</b>) <unsigned integer></dt>
<dd>
</dd>
<dt id="properties-OSSL_DRBG_PARAM_PROPERTIES-UTF8-string">"properties" (<b>OSSL_DRBG_PARAM_PROPERTIES</b>) <UTF8 string></dt>
<dd>
</dd>
<dt id="mac-OSSL_DRBG_PARAM_MAC-UTF8-string">"mac" (<b>OSSL_DRBG_PARAM_MAC</b>) <UTF8 string></dt>
<dd>
</dd>
<dt id="digest-OSSL_DRBG_PARAM_DIGEST-UTF8-string">"digest" (<b>OSSL_DRBG_PARAM_DIGEST</b>) <UTF8 string></dt>
<dd>
<p>These parameters work as described in <a href="../man3/EVP_RAND.html">"PARAMETERS" in EVP_RAND(3)</a>.</p>
</dd>
<dt id="fips-indicator-OSSL_DRBG_PARAM_FIPS_APPROVED_INDICATOR-integer">"fips-indicator" (<b>OSSL_DRBG_PARAM_FIPS_APPROVED_INDICATOR</b>) <integer></dt>
<dd>
</dd>
<dt id="digest-check-OSSL_DRBG_PARAM_FIPS_DIGEST_CHECK-integer">"digest-check" (<b>OSSL_DRBG_PARAM_FIPS_DIGEST_CHECK</b>) <integer></dt>
<dd>
<p>These parameters work as described in <a href="../man7/provider-rand.html">"PARAMETERS" in provider-rand(7)</a>.</p>
</dd>
</dl>
<h1 id="NOTES">NOTES</h1>
<p>When using the FIPS provider, only these digests are permitted (as per <a href="https://csrc.nist.gov/CSRC/media/Projects/cryptographic-module-validation-program/documents/fips%20140-3/FIPS%20140-3%20IG.pdf">FIPS 140-3 IG D.R</a>):</p>
<dl>
<dt id="SHA-1">SHA-1</dt>
<dd>
</dd>
<dt id="SHA2-256">SHA2-256</dt>
<dd>
</dd>
<dt id="SHA2-512">SHA2-512</dt>
<dd>
</dd>
<dt id="SHA3-256">SHA3-256</dt>
<dd>
</dd>
<dt id="SHA3-512">SHA3-512</dt>
<dd>
</dd>
</dl>
<p>A context for HMAC DRBG can be obtained by calling:</p>
<pre><code> EVP_RAND *rand = EVP_RAND_fetch(NULL, "HMAC-DRBG", NULL);
EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand, NULL);</code></pre>
<h1 id="EXAMPLES">EXAMPLES</h1>
<pre><code> EVP_RAND *rand;
EVP_RAND_CTX *rctx;
unsigned char bytes[100];
OSSL_PARAM params[3], *p = params;
unsigned int strength = 128;
rand = EVP_RAND_fetch(NULL, "HMAC-DRBG", NULL);
rctx = EVP_RAND_CTX_new(rand, NULL);
EVP_RAND_free(rand);
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_MAC, SN_hmac, 0);
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_DIGEST, SN_sha256, 0);
*p = OSSL_PARAM_construct_end();
EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params);
EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0);
EVP_RAND_CTX_free(rctx);</code></pre>
<h1 id="CONFORMING-TO">CONFORMING TO</h1>
<p>NIST SP 800-90A and SP 800-90B</p>
<h1 id="SEE-ALSO">SEE ALSO</h1>
<p><a href="../man3/EVP_RAND.html">EVP_RAND(3)</a>, <a href="../man3/EVP_RAND.html">"PARAMETERS" in EVP_RAND(3)</a>, <a href="../man1/openssl-fipsinstall.html">openssl-fipsinstall(1)</a></p>
<h1 id="HISTORY">HISTORY</h1>
<p>OpenSSL 3.1.1 introduced the <b>-no_drbg_truncated_digests</b> option to fipsinstall which restricts the permitted digests when using the FIPS provider in a complaint manner. For details refer to <a href="https://csrc.nist.gov/CSRC/media/Projects/cryptographic-module-validation-program/documents/fips%20140-3/FIPS%20140-3%20IG.pdf">FIPS 140-3 IG D.R</a>).</p>
<h1 id="COPYRIGHT">COPYRIGHT</h1>
<p>Copyright 2020-2024 The OpenSSL Project Authors. All Rights Reserved.</p>
<p>Licensed under the Apache License 2.0 (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>