Revision control
Copy as Markdown
Other Tools
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"[
<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd" >
%brandDTD;
]>
<head>
<title>Certificate Information and Decisions</title>
<link rel="stylesheet" href="helpFileLayout.css"
type="text/css"/>
</head>
<body>
<div class="boilerPlate">This document is provided for your information only.
It may help you take certain steps to protect the privacy and security of
your personal information on the Internet. This document does not, however,
address all online privacy and security issues, nor does it represent a
recommendation about what constitutes adequate privacy and security
protection on the Internet.</div>
<h1 id="certificate_information_and_decisions">Certificate Information and
Decisions</h1>
<p>This section describes how to use various windows displayed at different times by
Certificate Manager. The additional information given here appears when you click
the Help button in one of those windows.</p>
<div class="contentsBox">In this section:
<ul>
<li><a href="#certificate_viewer">Certificate Viewer</a></li>
<li><a href="#choose_security_device">Choose Security Device</a></li>
<li><a href="#encryption_key_copy">Encryption Key Copy</a></li>
<li><a href="#certificate_backup">Certificate Backup</a></li>
<li><a href="#user_identification_request">User Identification Request</a></li>
<li><a href="#new_certificate_authority">New Certificate Authority</a></li>
<li><a href="#website_certificates">Website Certificates</a></li>
</ul>
</div>
<h2 id="certificate_viewer">Certificate Viewer</h2>
<p>The Certificate Viewer displays information about a certificate you selected
in one of the Certificate Manager tabs. The General tab summarizes
information about who issued the certificate, its verification status, what
the certificate can be used for, and so on. The Details tab provides complete
details on the certificate's contents.</p>
<p>If you are not currently viewing the Certificate Viewer, follow these
steps:</p>
<ol>
<li>Open the <span class="mac">&brandShortName;</span>
<span class="noMac">Edit</span> menu and choose Preferences.</li>
<li>Under the Privacy & Security category, click Certificates. (If no
subcategories are visible, double-click Privacy & Security to expand
the list.)</li>
<li>Click Manage Certificates.</li>
<li>Click the tab for the type of certificate whose details you want to
view.</li>
<li>Select the certificate whose details you want to view.</li>
<li>Click View.</li>
</ol>
<div class="contentsBox">In this section:
<ul>
<li><a href="#general_tab">General Tab</a></li>
<li><a href="#details_tab">Details Tab</a></li>
</ul>
</div>
<h3 id="general_tab">General Tab</h3>
<p>When you first open the Certificate Viewer, the General tab displays several
kinds of information about the selected certificate:</p>
<ul>
<li><strong>This certificate has been verified for the following
uses</strong>: See
<a href="glossary.xhtml#certificate_verification">certificate verification</a>
for a discussion of how the Certificate Manager verifies certificates. Uses
can include any of the following:
<ul>
<li><strong>SSL Client Certificate</strong>: Certificate used to identify
you to websites.</li>
<li><strong>SSL Server Certificate</strong>: Certificate used to identify
a website server to browsers.</li>
<li><strong>Email Signer Certificate</strong>: Certificate used to
identify you for the purposes of digitally signing email messages.</li>
<li><strong>Email Recipient Certificate</strong>: Certificate used to
identify someone else, for example so you can send that person
encrypted email.</li>
<li><strong>Status Responder Certificate</strong>: Certificate used to
identify an online status responder that uses the Online Certificate
Status Protocol (OCSP) to check the validity of certificates. For more
information about OCSP, see
<a href="certs_prefs_help.xhtml">Certificates Settings</a>.</li>
<li><strong>SSL Certificate Authority</strong>: Certificate used to
identify a certificate authority—that is, a service that issues
certificates for use as identification over computer networks.</li>
</ul>
</li>
<li><strong>Issued To</strong>: Summarizes the following information about
the certificate:
<ul>
<li><strong>Common Name</strong>: The name of the person or other entity
that the certificate identifies.</li>
<li><strong>Organization</strong>: The name of the organization to which
the entity belongs (such as the name of a company).</li>
<li><strong>Organizational Unit</strong>: The name of the organizational
unit to which the entity belongs (such as Accounting Department).</li>
<li><strong>Serial Number</strong>: The certificate's serial
number.</li>
</ul>
</li>
<li><strong>Issued By</strong>: Summarizes information (similar to that
provided under <q>Issued To</q>; see above) about the certificate authority
(CA) that issued the certificate.</li>
<li><strong>Validity</strong>: Indicates the period during which the
certificate is valid.</li>
<li><strong>Fingerprints</strong>: Lists the certificate's fingerprints.
A fingerprint is a unique number produced by applying a mathematical
function to the certificate contents. A certificate's fingerprint can
be used to verify that the certificate has not been tampered with.</li>
</ul>
<h3 id="details_tab">Details Tab</h3>
<p>Click the Details tab at the top of the Certificate Viewer to see more
detailed information about the selected certificate. To examine information
for any certificate in the Certificate Hierarchy area, select its name,
select the field under Certificate Fields that you want to examine, and
read the field's value under Field Value:</p>
<ul>
<li><strong>Certificate Hierarchy</strong>: Displays the certificate chain,
with the certificate you originally selected at the bottom. A certificate
chain is a hierarchical series of certificates signed by successive
certificate authorities (CAs). A CA certificate identifies a
<a href="glossary.xhtml#certificate_authority">certificate authority</a>
and is used to sign certificates issued by that authority. A CA certificate
can in turn be signed by the CA certificate of a parent CA and so on up to
a <a href="glossary.xhtml#root_ca">root CA</a>.</li>
<li><strong>Certificate Fields</strong>: Displays the fields of the
certificate selected under Certificate Hierarchy.</li>
<li><strong>Field Value</strong>: Displays the value of the field selected
under Certificate Fields.</li>
</ul>
<p>The Certificate Viewer displays basic ANSI types in human-readable form
wherever possible. For fields whose contents the Certificate Manager cannot
interpret, it displays the actual values contained in the certificate.</p>
<h2 id="choose_security_device">Choose Security Device</h2>
<p>A security device (sometimes called a token) is a hardware or software
device that provides cryptographic services such as encryption and decryption
and stores certificates and keys. The Choose Security Device window appears
when Certificate Manager needs help deciding which security device to use
when importing a certificate or performing a cryptographic operation, such as
generating keys for a new certificate. This window allows you to select one
of two or more security devices that Certificate Manager has detected on your
machine.</p>
<p>A smart card is one example of a security device. For example, if a smart
card reader connected to your computer has a smart card inserted in it, the
name of the smart card will show up in the drop-down menu. In this case, you
must choose the name of the smart card from the menu to let Certificate
Manager know that you want to use it.</p>
<p>The Certificate Manager also supplies its own default, built-in security
device, which can always be used no matter what additional devices are or
aren't available.</p>
<h2 id="encryption_key_copy">Encryption Key Copy</h2>
<p><a href="glossary.xhtml#certificate_authority">Certificate authorities (CAs)</a>
that issue separate signing and encryption email certificates typically make
backup copies of your private
<a href="glossary.xhtml#encryption_key">encryption key</a> during the
certificate enrollment process.</p>
<p>The Encryption Key Copy dialog box allows you to approve the creation of
such a backup or cancel the certificate request. A CA that has archived a
backup copy of your encryption key has the potential capability of
decrypting any messages you receive that were encrypted with your
corresponding public key.</p>
<p>You can take these actions from the Encryption Key Copy dialog box:</p>
<ul>
<li><strong>View Certificate</strong>: To view the certificate identifying
the CA that is requesting the backup copy, click View Certificate.</li>
<li><strong>OK</strong>: If you trust the CA identified by the CA certificate
to decrypt encrypted messages that you receive, click OK.
<p>If you are not sure whether to trust the CA that is requesting the
backup copy, talk to your system administrator.</p>
</li>
<li><strong>Cancel</strong>: If you don't trust the CA that is
requesting the backup copy, don't request a certificate from it. Click
Cancel to stop both the backup procedure and the request for a
certificate.</li>
</ul>
<p>After your CA makes a backup copy of the encryption key, you will be able to
use that key to access your encrypted mail even if you lose your password or
lose your own copy of the key. If no backup copy of your encryption key
exists and you lose your password or the key, you will have no way of reading
email messages that were encrypted with that key.</p>
<h2 id="certificate_backup">Certificate Backup</h2>
<p>When you receive a certificate, make a backup copy of the certificate and
its private key, then store the copy in a safe place. For example, you can
put the copy on a floppy disk and store it with other valuable items under
lock and key. That way, even if you have hard disk or file corruption
problems, you can easily restore the certificate.</p>
<p>It can be inconvenient, at best, and in some situations catastrophic to lose
your certificate and its associated private key, depending on what you use it
for. For example:</p>
<ul>
<li>If you lose a certificate that identifies you to important websites, you
will not be able to access those websites until you obtain a new
certificate. </li>
<li>If you lose a certificate used to encrypt email messages, you will not
be able to read any of your encrypted email—including both encrypted
messages that you have sent and encrypted messages that you have received.
In this case, if you cannot obtain a backup of the private encryption key
associated with the certificate, you will never be able to read any of the
messages encrypted with that key.</li>
</ul>
<p>Like any other valuable data, certificates should be backed up to avoid
future trouble and expense. Do it now so you don't forget.</p>
<h2 id="user_identification_request">User Identification Request</h2>
<p>Some websites require that you identify yourself with a certificate rather
than a name and password, because certificates provide a more reliable form
of identification. This method of identifying yourself over the Internet is
sometimes called
<a href="glossary.xhtml#client_authentication">client authentication</a>.</p>
<p>However, Certificate Manager may have more than one certificate on file that
can be used for the purposes of identifying yourself to a website. In this
case, Certificate Manager presents the User Identification Request dialog
box, which displays two kinds of information:</p>
<p><strong>This site has requested that you identify yourself with a
certificate</strong>: This section of the dialog box lists the following
information:</p>
<ul>
<li><strong>Host name</strong>: The name of the server requesting
identification, used as part of its URL. For example, the host name for the
Netscape website is <tt>home.netscape.com</tt>.</li>
<li><strong>Organization</strong>: The name of the organization that runs the
website.</li>
<li><strong>Issued under</strong>: The name of the
<a href="glossary.xhtml#certificate_authority">certificate authority (CA)</a>
that issued the certificate.</li>
</ul>
<p><strong>Choose a certificate to present as identification</strong>: The
certificates you have available for the purposes of identifying yourself to a
website are listed in the drop-down list in this section of the dialog box.
Choose the certificate that seems most likely to be recognized by the website
you want to visit.</p>
<p>To help you decide, the following details of the selected certificate are
displayed:</p>
<ul>
<li><strong>Issued to</strong>: Lists information about the person identified
by the certificate (for example, your name and email address) and the
certificate's serial number and validity dates.</li>
<li><strong>Issued by</strong>: Summarizes information about the CA that
issued the certificate, such as its name, location, and state.</li>
</ul>
<h2 id="new_certificate_authority">New Certificate Authority</h2>
<p>The certificates that the Certificate Manager has on file, whether stored on
your computer or on an external security device such as a smart card, include
certificates that identify
<a href="glossary.xhtml#certificate_authority">certificate authorities (CAs)</a>.
To be able to recognize any other certificates it has on file, Certificate
Manager must have certificates for the CAs that issued or authorized issuance
of those certificates.</p>
<p>When you decide to trust a CA, Certificate Manager downloads that CA's
certificate and can then recognize the kinds of certificates you trust that
CA to issue.</p>
<p>Before downloading a new CA certificate, Certificate Manager allows you to
specify the purposes for which you trust the certificate, if at all. You can
select any of the following options:</p>
<ul>
<li><strong>Trust this CA to identify websites</strong>: Website certificates
for some websites, such as those that handle financial transactions, can be
extremely important, and inappropriate or false identification can have
negative consequences.</li>
<li><strong>Trust this CA to identify email users</strong>: If you intend to
send email users confidential information in encrypted form, or if accurate
identification of email users is important to you for any other reason, you
should consider carefully the CA's procedures for identifying
prospective certificate owners and whether they are appropriate for your
purposes before selecting this option.</li>
<li><strong>Trust this CA to identify software developers</strong>: Selecting
this option means that you trust the CA to issue certificates that identify
the origin of JavaScript scripts requesting special access to your computer,
such as the ability to change files. Since such access privileges can be
misused, for example to destroy data stored on your hard disk, be very
careful about selecting this option unless you are certain that you trust
the CA for this purpose.</li>
</ul>
<p>Before you decide to trust a new CA, make sure that you know who is
operating it. Make sure the CA's policies and procedures are
appropriate for the kinds of certificates it issues. For example, if the CA
issues certificates identifying websites you use for financial transactions,
make sure you are comfortable with the level of assurance the CA
provides.</p>
<ul>
<li><strong>View</strong>: Click this button to view the CA certificate you
are about to download. If you decide you don't want to download this
certificate, click Cancel.</li>
</ul>
<h2 id="website_certificates">Website Certificates</h2>
<p>When you attempt to go to a website that supports the use of
<a href="glossary.xhtml#ssl">SSL</a> for
<a href="glossary.xhtml#authentication">authentication</a> and
<a href="glossary.xhtml#encryption">encryption</a>, you may be faced with an
error page. There are two types, one called
<a href="#secure_connection_failed_page">Secure Connection Failed</a> and one
called <a href="#untrusted_connection_page">Untrusted Connection</a>.</p>
<div class="contentsBox">In this section:
<ul>
<li><a href="#secure_connection_failed_page">Secure Connection Failed
Page</a></li>
<li><a href="#untrusted_connection_page">Untrusted Connection Page</a></li>
<li><a href="#secure_connection_failed_dialog">Secure Connection Failed
Dialog</a></li>
<li><a href="#certificate_expired">Server Certificate Expired</a></li>
<li><a href="#certificate_not_yet_valid">Server Certificate Not Yet
Valid</a></li>
<li><a href="#domain_name_mismatch">Domain Name Mismatch</a></li>
</ul>
</div>
<h3 id="secure_connection_failed_page">Secure Connection Failed Page</h3>
<p>In the case where you have disabled the SSL protocol (e.g. through
<a href="ssl_help.xhtml#ssltls_settings">SSL/TLS Settings</a>) or the website
that you are accessing is using an older, insecure version of the SSL protocol
then you will be presented with a page titled "Secure Connection
Failed". That page contains some basic background information (including
the <strong>Error code</strong> that uniquely identifies the type of problem
&brandShortName; detected with the website) and a <strong>Try Again</strong>
button that triggers a page reload.</p>
<h3 id="untrusted_connection_page">Untrusted Connection Page</h3>
<p>If SSL itself is enabled then the error page that you will be presented with
will be titled "This Connection is Untrusted". There are many
different reasons why a connection can appear untrusted. Here are some of the
most common ones:</p>
<ul>
<li>the certificate of the website is <a href="#certificate_expired">no longer
valid (expired)</a></li>
<li>the certificate of the website is
<a href="#certificate_not_yet_valid">not yet valid</a></li>
<li>the certificate of the website is only valid for another website
(<a href="#domain_name_mismatch">domain name mismatch</a>)</li>
<li>the certificate of the website is self-signed (thus the identity of the
website cannot be verified).</li>
<li>the issuer certificate is not trusted (&brandShortName; cannot
verify the identity of the website because it doesn't
recognize the <a href="glossary.xhtml#certificate_authority">certificate
authority (CA)</a> that issued the website's certificate)</li>
</ul>
<p>The page displayed in the above cases is meant to help you understand why
&brandShortName; was unable to establish a secure connection to the website.
It starts by telling you that the website's identity could not be
verified, then offers you to leave the page by clicking the <strong>This
sounds bad, take me to my home page instead</strong> button. If you are unsure
what to do it is recommended that you follow this advice.</p>
<p>If you want to know a little bit more about the actual problem at hand you
may expand the corresponding section by clicking the chevron in front of
<strong>Technical Details</strong>. That section also contains the
<strong>Error code</strong> that uniquely identifies the type of problem
&brandShortName; detected with the website.</p>
<h4 id="add_security_exception">Adding a Security Exception</h4>
<p>The <strong>I Understand the Risks</strong> section of the Untrusted
Connection page allows you to tell &brandShortName; to explicitly override the
security checks for this website by adding an exception. If you expand the
section by clicking the chevron in front of it you will see an <strong>Add
Exception</strong> button that will take you to a dialog allowing you to get
and view the website's certificate and optionally add a Security
Exception for it (either permanently or just for the current session). Those
exceptions can be administered through the Certificate Manager's
<a href="certs_help.xhtml#servers">Servers</a> tab.</p>
<h3 id="secure_connection_failed_dialog">Secure Connection Failed Dialog</h3>
<p>In cases where &brandShortName; cannot determine the actual cause of the
problem a dialog titled "Secure Connection Failed" is shown in
addition to the <a href="#untrusted_connection_page">Untrusted Connection
page</a>. That dialog includes a <strong>View Certificate</strong> button
that allows you to examine the website's certificate more closely.</p>
<h3 id="certificate_expired">Certificate Expired</h3>
<p>Like a credit card, a driver's license, and many other forms of
identification, a <a href="glossary.xhtml#certificate">certificate</a> is
valid for a specified period of time. When a certificate expires, the owner
of the certificate needs to get a new one.</p>
<p>&brandShortName; <a href="#untrusted_connection_page">warns</a> you when you
attempt to visit a website whose server certificate has expired. The first
thing you should do is make sure the time and date displayed by your computer
is correct. If your computer's clock is set to a date that is after the
expiration date, &brandShortName; treats the website's certificate as
expired.</p>
<p>If your computer's clock is set correctly, you need to make a decision
about whether to trust the website. This decision depends on what you intend
to do at the website and what else you know about it. Most commercial sites
will make sure that they replace their certificates before they expire. If you
choose to continue you need to <a href="#add_security_exception">add a
security exception</a>.</p>
<h3 id="certificate_not_yet_valid">Certificate Not Yet Valid</h3>
<p>Like a credit card, a driver's license, and many other forms of
identification, a <a href="glossary.xhtml#certificate">certificate</a> is
valid for a specified period of time.</p>
<p>&brandShortName; <a href="#untrusted_connection_page">warns</a> you when you
attempt to visit a website whose server certificate's validity period has
not yet started. The first thing you should do is make sure the time and date
displayed by your own computer is correct. If your computer's clock is
set to the wrong date, &brandShortName; may treat the server certificate as
not yet valid even if this is not the case.</p>
<p>If your computer's clock is set correctly, you need to make a decision
about whether to trust the website. This decision depends on what you intend
to do at the website and what else you know about it. Most commercial sites
will make sure that the validity period for their certificates has begun
before beginning to use them. If you choose to continue you need to
<a href="#add_security_exception">add a security exception</a>.</p>
<h3 id="domain_name_mismatch">Domain Name Mismatch</h3>
<p>A server <a href="glossary.xhtml#certificate">certificate</a> specifies the
name of the server in the form of the website's domain name. For example,
the domain name for the Mozilla website is <tt>www.mozilla.org</tt>. If the
domain name in a server's certificate doesn't match the actual
domain name of the website, it may be a sign that someone is attempting to
intercept your communication with the website.</p>
<p>&brandShortName; <a href="#untrusted_connection_page">warns</a> you when you
attempt to visit a website whose server certificate's domain does not
match the domain of the website you are trying to visit. The decision whether
to trust the website anyway depends on what you intend to do at the site and
what else you know about it. Most commercial sites will make sure that the
host name for a website certificate matches the website's actual host
name. If you choose to continue you need to
<a href="#add_security_exception">add a security exception</a>.</p>
<p>If you decide to accept the certificate anyway (either for this session or
permanently), you should be cautious about what you do on the website, and you
should treat any information you find there as potentially suspect.</p>
</body>
</html>