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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.

# Certificate Information and Decisions

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.

In this section:

- Certificate Viewer
- Choose Security Device
- Encryption Key Copy
- Certificate Backup
- User Identification Request
- New Certificate Authority
- Website Certificates

## Certificate Viewer

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.

If you are not currently viewing the Certificate Viewer, follow these steps:

1. Open the &brandShortName; Edit menu and choose Preferences.
2. Under the Privacy & Security category, click Certificates. (If no subcategories are visible, double-click Privacy & Security to expand the list.)
3. Click Manage Certificates.
4. Click the tab for the type of certificate whose details you want to view.
5. Select the certificate whose details you want to view.
6. Click View.

In this section:

- General Tab
- Details Tab

### General Tab

When you first open the Certificate Viewer, the General tab displays several kinds of information about the selected certificate:

- This certificate has been verified for the following uses: See certificate verification for a discussion of how the Certificate Manager verifies certificates. Uses can include any of the following:
  - SSL Client Certificate: Certificate used to identify you to websites.
  - SSL Server Certificate: Certificate used to identify a website server to browsers.
  - Email Signer Certificate: Certificate used to identify you for the purposes of digitally signing email messages.
  - Email Recipient Certificate: Certificate used to identify someone else, for example so you can send that person encrypted email.
  - Status Responder Certificate: 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 Validation Settings.
  - SSL Certificate Authority: Certificate used to identify a certificate authority—that is, a service that issues certificates for use as identification over computer networks.
- Issued To: Summarizes the following information about the certificate:
  - Common Name: The name of the person or other entity that the certificate identifies.
  - Organization: The name of the organization to which the entity belongs (such as the name of a company).
  - Organizational Unit: The name of the organizational unit to which the entity belongs (such as Accounting Department).
  - Serial Number: The certificate's serial number.
- Issued By: Summarizes information (similar to that provided under Issued To; see above) about the certificate authority (CA) that issued the certificate.
- Validity: Indicates the period during which the certificate is valid.
- Fingerprints: 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.

### Details Tab

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:

- Certificate Hierarchy: 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 certificate authority 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 root CA.
- Certificate Fields: Displays the fields of the certificate selected under Certificate Hierarchy.
- Field Value: Displays the value of the field selected under Certificate Fields.

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.

## Choose Security Device

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.

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.

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.

## Encryption Key Copy

Certificate authorities (CAs) that issue separate signing and encryption email certificates typically make backup copies of your private encryption key during the certificate enrollment process.

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.

You can take these actions from the Encryption Key Copy dialog box:

- View Certificate: To view the certificate identifying the CA that is requesting the backup copy, click View Certificate.
- OK: If you trust the CA identified by the CA certificate to decrypt encrypted messages that you receive, click OK.

  If you are not sure whether to trust the CA that is requesting the backup copy, talk to your system administrator.

- Cancel: 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.

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.

## Certificate Backup

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.

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:

- 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.
- 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.

Like any other valuable data, certificates should be backed up to avoid future trouble and expense. Do it now so you don't forget.

## User Identification Request

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 client authentication.

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:

This site has requested that you identify yourself with a certificate: This section of the dialog box lists the following information:

- Host name: The name of the server requesting identification, used as part of its URL. For example, the host name for the Netscape website is `home.netscape.com`.
- Organization: The name of the organization that runs the web site.
- Issued under: The name of the certificate authority (CA) that issued the certificate.

Choose a certificate to present as identification: 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.

To help you decide, the following details of the selected certificate are displayed:

- Issued to: 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.
- Issued by: Summarizes information about the CA that issued the certificate, such as its name, location, and state.

## New Certificate Authority

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 certificate authorities (CAs). 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.

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.

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:

- Trust this CA to identify websites: Website certificates for some sites, such as those that handle financial transactions, can be extremely important, and inappropriate or false identification can have negative consequences.
- Trust this CA to identify email users: 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.
- Trust this CA to identify software developers: Selecting this option means that you trust the CA to issue certificates that identify the origin of Java applets and 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.

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.

- View: 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.

## Website Certificates

One of the windows listed here may appear when you attempt to go to a website that supports the use of SSL for authentication and encryption.

In this section:

- Website Certified by an Unknown Authority
- Server Certificate Expired
- Server Certificate Not Yet Valid
- Domain Name Mismatch

### Website Certified by an Unknown Authority

Many websites use certificates to identify themselves when you visit the site. If Certificate Manager doesn't recognize the certificate authority (CA) that issued a website's certificate, it displays an alert that allows you to examine the new website certificate and decide what to do.

- Examine Certificate: Click this button to view the website's certificate.

You can choose one of these options from this alert:

- Accept this certificate permanently. Select this option to accept the certificate (despite the apparent problem) and connect to the website. Certificate Manager will recognize this certificate as legitimate identification until the certificate expires.
- Accept this certificate temporarily for this session. Select this option to accept the certificate temporarily and connect to the website. Certificate Manager will recognize this certificate as legitimate identification only until the next time you launch the browser. You may see the same alert the next time you attempt to visit the website.
- Do not accept this certificate and do not connect to this website. Select this option if you decide not to visit the website at all. This option might be appropriate, for example, if you perform financial transactions at the website. In this case you might want to report the problem to the bank or other organization that runs the site and confirm that the site's certificate is valid before you go any further.

Click OK to confirm your choice. If you click Cancel, Certificate Manager will not recognize the certificate as legitimate identification and will not connect to the web site.

Important note for server administrators: This alert may be triggered by a server that is not configured correctly. To find out if this is the case, the server administrator or webmaster for the site you are attempting to visit should check the status of any required intermediate CAs and if necessary, install the missing certificate in the server.

If you decide to contact the website's webmaster about this issue, you can include the following information:

- The server administrator can obtain more information about intermediate CAs from here: http://kb.verisign.com/esupport/esupport/consumer/esupport.asp?id=vs2119
- If the server is using a VeriSign certificate, the server administrator can download the appropriate certificate from here: http://www.verisign.com/support/install/index.html

For advanced users: To ensure that Certificate Manager trusts all certificates issued by a given CA, you can edit the trust settings for the corresponding CA certificate. To do so, follow these steps:

1. Open the &brandShortName; Edit menu and choose Preferences.
2. Under the Privacy & Security category, click Certificates. (If no subcategories are visible, double-click Privacy & Security to expand the list.)
3. Click Manage Certificates.
4. Click the Authorities tab.
5. Select the CA certificate whose trust settings you want to edit.
6. Click the Edit button and select the appropriate trust settings.

### Server Certificate Expired

Like a credit card, a driver's license, and many other forms of identification, a certificate is valid for a specified period of time. When a certificate expires, the owner of the certificate needs to get a new one.

Certificate Manager warns 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, Certificate Manager treats the website's certificate as expired.

If your computer's clock is set correctly, you need to make a decision about whether to trust the site. This decision depends on what you intend to do at the site and what else you know about it. Most commercial sites will make sure that they replace their certificates before they expire.

You can take these actions from the Expired Server Certificate dialog box:

- View Certificate: To examine information about the certificate, including its validity period, click View Certificate.
- Continue: If you have reason to believe the certificate's expiration is an inadvertent error, you may choose to click Continue to accept the certificate anyway for this session, and let the webmaster for the site know about the problem.

  Be cautious about any actions you take while you are visiting the site.

- Cancel: If you suspect that there may be a significant problem and you don't want to risk visiting the site at all, click Cancel (in which case Certificate Manager will not connect you to the site).

### Server Certificate Not Yet Valid

Like a credit card, a driver's license, and many other forms of identification, a certificate is valid for a specified period of time.

Certificate Manager warns 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, Certificate Manager may treat the server certificate as not yet valid even if this is not the case.

If your computer's clock is set correctly, you need to make a decision about whether to trust the site. This decision 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 validity period for their certificates has begun before beginning to use them.

You can take these actions from the Server Certificate Not Yet Valid dialog box:

- View Certificate: To examine information about the certificate, including its validity period, click View Certificate.
- OK: If you have reason to believe the problem is an inadvertent error, you may choose to click OK to accept the certificate anyway for this session, and let the webmaster for the site know about the problem.

  Be cautious about any actions you take while you are visiting the site.

- Cancel: If you suspect that there may be a significant problem and you don't want to risk visiting the site at all, click Cancel (in which case Certificate Manager will not connect you to the site).

### Domain Name Mismatch

A server certificate specifies the name of the server in the form of the site's domain name. For example, the domain name for the Mozilla website is `www.mozilla.org`. 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.

The decision whether to trust the site 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.

You can take these actions from the Domain Name Mismatch dialog box:

- View Certificate: To examine information about the certificate, click View Certificate.
- OK: If you have reason to believe the problem is an inadvertent error, you may choose to click OK to accept the certificate anyway for this session, and let the webmaster for the site know about the problem.

  Be cautious about any actions you take while you are visiting the site, and treat any information you find there as potentially suspect.

- Cancel: If you suspect that there may be a significant problem and you don't want to risk visiting the site at all, click Cancel (in which case Certificate Manager will not connect you to the site).

If you decide to accept the certificate anyway for this session, you should be cautious about what you do on the website, and you should treat any information you find there as potentially suspect.

Copyright © 2003-2005 The Mozilla Foundation.