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<!-- This manual is last updated 4 March 2015 for version
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Copyright (C) 2001-2015 Nikos Mavrogiannopoulos
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<title>GnuTLS 3.5.3: Hardware security modules and abstract key types</title>
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<a name="Hardware-security-modules-and-abstract-key-types"></a>
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<p>
Next: <a href="How-to-use-GnuTLS-in-applications.html#How-to-use-GnuTLS-in-applications" accesskey="n" rel="next">How to use GnuTLS in applications</a>, Previous: <a href="Authentication-methods.html#Authentication-methods" accesskey="p" rel="prev">Authentication methods</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Function-and-Data-Index.html#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Abstract-keys-types-and-Hardware-security-modules"></a>
<h2 class="chapter">5 Abstract keys types and Hardware security modules</h2>
<p>In several cases storing the long term cryptographic keys in a hard disk or
even in memory poses a significant risk. Once the system they are stored
is compromised the keys must be replaced as the secrecy of future sessions
is no longer guaranteed. Moreover, past sessions that were not protected by a
perfect forward secrecy offering ciphersuite are also to be assumed compromised.
</p>
<p>If such threats need to be addressed, then it may be wise storing the keys in a security
module such as a smart card, an HSM or the TPM chip. Those modules ensure the
protection of the cryptographic keys by only allowing operations on them and
preventing their extraction. The purpose of the abstract key API is to provide
an API that will allow the handle of keys in memory and files, as well as keys
stored in such modules.
</p>
<p>In GnuTLS the approach is to handle all keys transparently by the high level API, e.g.,
the API that loads a key or certificate from a file.
The high-level API will accept URIs in addition to files that specify keys on an HSM or in TPM,
and a callback function will be used to obtain any required keys. The URI format is defined in
[<em>PKCS11URI</em>].
</p>
<p>More information on the API is provided in the next sections. Examples of a URI of a certificate
stored in an HSM, as well as a key stored in the TPM chip are shown below. To discover the URIs
of the objects the <code>p11tool</code> (see <a href="p11tool-Invocation.html#p11tool-Invocation">p11tool Invocation</a>).
</p><div class="example">
<pre class="example">pkcs11:token=Nikos;serial=307521161601031;model=PKCS%2315; \
manufacturer=EnterSafe;object=test1;type=cert
</pre></div>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">• <a href="Abstract-key-types.html#Abstract-key-types" accesskey="1">Abstract key types</a>:</td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">• <a href="Application_002dspecific-keys.html#Application_002dspecific-keys" accesskey="2">Application-specific keys</a>:</td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">• <a href="Smart-cards-and-HSMs.html#Smart-cards-and-HSMs" accesskey="3">Smart cards and HSMs</a>:</td><td> </td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">• <a href="Trusted-Platform-Module.html#Trusted-Platform-Module" accesskey="4">Trusted Platform Module</a>:</td><td> </td><td align="left" valign="top">
</td></tr>
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Next: <a href="How-to-use-GnuTLS-in-applications.html#How-to-use-GnuTLS-in-applications" accesskey="n" rel="next">How to use GnuTLS in applications</a>, Previous: <a href="Authentication-methods.html#Authentication-methods" accesskey="p" rel="prev">Authentication methods</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Function-and-Data-Index.html#Function-and-Data-Index" title="Index" rel="index">Index</a>]</p>
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