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<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
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<modulesynopsis metafile="mod_session_crypto.xml.meta">

<name>mod_session_crypto</name>
<description>Session encryption support</description>
<status>Experimental</status>
<sourcefile>mod_session_crypto.c</sourcefile>
<identifier>session_crypto_module</identifier>
<compatibility>Available in Apache 2.3 and later</compatibility>

<summary>
    <note type="warning"><title>Warning</title>
      <p>The session modules make use of HTTP cookies, and as such can fall
      victim to Cross Site Scripting attacks, or expose potentially private
      information to clients. Please ensure that the relevant risks have
      been taken into account before enabling the session functionality on
      your server.</p>
    </note>

    <p>This submodule of <module>mod_session</module> provides support for the
    encryption of user sessions before being written to a local database, or
    written to a remote browser via an HTTP cookie.</p>
    
    <p>This can help provide privacy to user sessions where the contents of
    the session should be kept private from the user, or where protection is
    needed against the effects of cross site scripting attacks.</p>
    
    <p>For more details on the session interface, see the documentation for
    the <module>mod_session</module> module.</p>
    
</summary>
<seealso><module>mod_session</module></seealso>
<seealso><module>mod_session_cookie</module></seealso>
<seealso><module>mod_session_dbd</module></seealso>

    <section id="basicusage"><title>Basic Usage</title>
    
      <p>To create a simple encrypted session and store it in a cookie called
      <var>session</var>, configure the session as follows:</p>
      
      <example><title>Browser based encrypted session</title>
        Session On<br />
        SessionCookieName session path=/<br />
        SessionCryptoPassphrase secret
      </example>
      
      <p>The session will be encrypted with the given key. Different servers can
      be configured to share sessions by ensuring the same encryption key is used
      on each server.</p>
      
      <p>If the encryption key is changed, sessions will be invalidated
      automatically.</p>
      
      <p>For documentation on how the session can be used to store username
      and password details, see the <module>mod_auth_form</module> module.</p>

    </section>

<directivesynopsis>
<name>SessionCryptoDriver</name>
<description>The crypto driver to be used to encrypt the session</description>
<syntax>SessionCryptoDriver <var>name</var> <var>[param[=value]]</var></syntax>
<default>none</default>
<contextlist><context>server config</context>
</contextlist>
<compatibility>Available in Apache 2.3.0 and later</compatibility>

<usage>
    <p>The <directive>SessionCryptoDriver</directive> directive specifies the name of
    the crypto driver to be used for encryption. If not specified, the driver defaults
    to the recommended driver compiled into APR-util.</p>

    <p>The <var>NSS</var> crypto driver requires some parameters for configuration,
    which are specified as parameters with optional values after the driver name.</p>

    <example><title>NSS without a certificate database</title>
      SessionCryptoDriver nss
    </example>

    <example><title>NSS with certificate database</title>
      SessionCryptoDriver nss dir=certs
    </example>

    <example><title>NSS with certificate database and parameters</title>
      SessionCryptoDriver nss dir=certs key3=key3.db cert7=cert7.db secmod=secmod
    </example>

    <p>The <var>NSS</var> crypto driver might have already been configured by another
    part of the server, for example from <module>mod_nss</module> or
    <module>mod_ldap</module>. If found to have already been configured,
    a warning will be logged, and the existing configuration will have taken affect.
    To avoid this warning, use the noinit parameter as follows.</p>

    <example><title>NSS with certificate database</title>
      SessionCryptoDriver nss noinit
    </example>

    <p>To prevent confusion, ensure that all modules requiring NSS are configured with
    identical parameters.</p>

</usage>
</directivesynopsis>

<directivesynopsis>
<name>SessionCryptoPassphrase</name>
<description>The key used to encrypt the session</description>
<syntax>SessionCryptoPassphrase <var>secret</var></syntax>
<default>none</default>
<contextlist><context>server config</context>
<context>virtual host</context>
<context>directory</context>
<context>.htaccess</context>
</contextlist>
<compatibility>Available in Apache 2.3.0 and later</compatibility>

<usage>
    <p>The <directive>SessionCryptoPassphrase</directive> directive specifies the key
    to be used to enable symmetrical encryption on the contents of the session before
    writing the session, or decrypting the contents of the session after reading the
    session.</p>

    <p>Keys are more secure when they are long, and consist of truly random characters.
    Changing the key on a server has the effect of invalidating all existing sessions.</p>

    <p>The cipher can be set to <var>3des192</var> or <var>aes256</var> using the
    <var>cipher</var> parameter as per the example below. If not set, the cipher defaults
    to <var>aes256</var>.</p>
    
    <example><title>Cipher</title>
      SessionCryptoPassphrase secret cipher=aes256
    </example>

    <p>The <var>openssl</var> crypto driver supports an optional parameter to specify
    the engine to be used for encryption.</p>

    <example><title>OpenSSL with engine support</title>
      SessionCryptoPassphrase secret engine=name
    </example>

</usage>
</directivesynopsis>

</modulesynopsis>
