DoD Common Access Card (CAC) Reader

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This is to help setup DoD Common Access Card (CAC) Reader also known as a Smart Card Reader. This procedure is tested to work with the DoD CAC, Oberthur ID One 128 v5.5 Dual.

Tested on openSUSE

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US Department of Defense (DoD) now limits access to many of its websites to be via a smart Common Access Card (CAC) authenticated with a Personal Identification Number (PIN). The following is a guide to assist in setting up openSUSE to access CAC-enabled DoD websites.


SLES 12 specific instructions can be found here:

Install the Middleware

The Linux CAC Reader stack is based on a set of middleware called PCSC (Personal Computer Smart Card), written by the MUSCLE (Movement for the Use of Smart Cards in a Linux Environment) project.

Packages available through openSUSE

In order to use the DoD CAC you must install the the following packages:

Alternatively, install the packages Through Terminal:

sudo zypper install pcsc-lite pcsc-ccid perl-pcsc pcsc-tools

PKCS #11 module

There are three working modules to access the PKCS #11 keys on your CAC. Each have their strengths and limitations. You will need to choose which version works best for you. In most situations, CoolKey is preferred.


OpenSC provides a set of utilities to access smart cards. It facilitates their use in security applications such as mail encryption, authentication, and digital signature. This module has a broader feature set than CoolKey or CACkey and you are able to access your PIV certificate for those individuals that are Dual Persona. This module is speedy like CoolKey and doesn't lag like CACkey. This may be the best option if you are dual persona and do not wish to use CACkey from DISA.

Alternatively, install OpenSC Through Terminal:

sudo zypper install opensc


Coolkey is available through the openSUSE software repository. This is arguably the most stable method for accessing your CAC. The downside is, Dual Persona individuals that have the activated PIV certificate will not be able to access it rendering you not able to access the DoD Enterprise Email certificates. If you are not Dual Persona this is by far the best module to use as it is stable, accesses certificates quickly and does not cause the pcsc daemon to hang. At the time of update, PIV certificates do not work with Coolkey. Direct link to the software package:

Alternatively, install CoolKey Through Terminal:

sudo zypper install coolkey

Smart Card Reader Driver

Without installing any additional drivers the following card readers are tested and work without issue:

SCR3310 by SCM Microsystems (Currently being issued to members by the US Army for use on personal computers)
SCR3500 by SCM Microsystems (Many members purchase this as a more compact alternative to the SCR3310)
O2 Micro, Inc (built-in to many Dell laptops)
  • You may have to install additional drivers for your hardware. Check your hardware and search using the key word pcsc.

Start Up the Daemon

This should happen automatically, but if it does not start up on your system, here is how you can activate/enable the SmartCard daemon:

Graphical Method

  • From YaST:
    • Open YaST
    • System Services (Runlevel)
    • Select the Expert Mode Radio button
    • Search for pcscd, select from the drop down Start/Stop/Refresh select Start
    • Select "OK" to close the window

Terminal Method

sudo systemctl start pcscd
sudo systemctl enable pcscd

Testing your Smart Card Driver

Open a terminal (ie konsole, x-term or other) and type/enter. You might have to insert a smart card in order for the message to pop-up.


Similar to the following means the card reader is working properly:

PC/SC device scanner
V 1.4.18 (c) 2001-2011, Ludovic Rousseau <>
Compiled with PC/SC lite version: 1.8.8
Using reader plug'n play mechanism
Scanning present readers...
0: O2 Micro Oz776 00 00

Sun Mar 24 11:40:07 2013
Reader 0: O2 Micro Oz776 00 00
  Card state: Card removed, 

Similar to this indicates a need to check for additional driver requirements for your hardware:

PC/SC device scanner
V 1.4.18 (c) 2001-2011, Ludovic Rousseau <>
Compiled with PC/SC lite version: 1.8.8
Using reader plug'n play mechanism
Scanning present readers...
Waiting for the first reader...

Then check again to see if the PCSC Daemon (pcscd) is running.

Verify SmartCard Deamon is Active and Reading Your CAC

At anytime if you don't seem to get response from the SmartCard, check and see if the daemon is active by executing this in terminal:


If you remove and insert your card with no response during the scan, the daemon has crashed.

If you find that the pcsc daemon has crashed you can run this in terminal to restart the daemon:

sudo systemctl restart pcscd

Authority Certificates

Download extract and install the DoD Certificates.

The certificates can be obtained from this link:

Make note of the location you stored these certificates

Configure Firefox

Firefox requires manual selection of the PKCS #11 module.

The aforementioned DoD Configuration extension has been deprecated and will no longer install into Firefox.

Import Certificates

The current method of installing the certificates is one-by-one. This can be done through Firefox import mechanism.

Firefox 57 and later

  • Preferences > Privacy & Security
    • Scroll Down to Security Section
    • Select View Certificates

Continue for All versions of Firefox

  • Select the Import... button at the bottom of the dialog.

The certificates that require installation are the following

  • Certificates_PKCS7_v5.10_WCF_DoD_WCF_Root_CA_1.der.p7b
  • Certificates_PKCS7_v5.10_WCF.der.p7b
  • Certificates_PKCS7_v5.10_WCF.pem.p7b

Set Firefox to Require Selection of Certificate

When accessing multiple CAC protected pages, some pages will require different certificates from the card. Some require the non-email certificate while Enterprise Email will require the email certificate.

Firefox 57 and later

  • Preferences > Privacy & Security
    • Scroll Down to Security Section
    • Below the Certificates heading, select the radio button in front of "Ask me every time."

Set CAC Module

Firefox 57 and later

  • Open Preferences > Privacy & Security
    • Scroll Down to Security Section
    • Select Security Devices

Continue for All versions of Firefox

  • Check the left column. It should show an entry similar to "CAC Module" along with certificate(s) as a sub-item. If it doesn't work then the entries are wrong.
    • Select the entry and select Unload to remove the security device
  • To install/reinstall the CAC driver in Firefox using the above listed Security Devices
    • Select Load on the dialog box
    • Module name should be something like: DoD CAC
    • Module filename: either type in or browse to the location of the, or drivers
    • The files will be located under either:



Configure Chrome / Chromium

Unfortunately, Chrome (Chromium) doesn't automatically recognize the CAC once you've completed all the previous steps but it doesn't take much more work to get Chrome to work with the CAC.

In order to utilize the CAC within Chrome it is necessary to install mozilla-nss-tools. You can do so through the openSUSE software installation site or through terminal:

sudo zypper install mozilla-nss-tools

While in a terminal in your home directory run one of the two following commands as your user:

  • For 32-bit systems:
modutil -dbdir sql:.pki/nssdb/ -add "CAC Module" -libfile /usr/lib/
  • For 64-bit systems:
modutil -dbdir sql:.pki/nssdb/ -add "CAC Module" -libfile /usr/lib64/

Make sure that the utility is properly installed

modutil -dbdir sql:.pki/nssdb/ -list

If it is properly installed there will be an entry with "CAC Module" and details of the library, slot and status. If you were not in your home directory when configuring modutil you will receive an error like "modutil: function failed: SEC_ERROR_BAD_DATABASE: security library: bad database."

Chrome should now be able to utilize the CAC without any issues

Removing CAC Module

If you have previously installed and you wish to utilize CoolKey instead, you will have to unload the "CAC Module":

modutil -dbdir sql:.pki/nssdb/ -delete "CAC Module"

Test out your browser

Go to a CAC-enabled web site ( and test the CAC login.

Be patient as there may be a delay while authenticating with the CAC.

The PIN and certificate selection authentication process is in the reverse of what you may be used to when using non-Linux machines. Expect to be prompted first for PIN and then certificate selection.


It is possible that the PCSC Daemon can hang, to restart the service in terminal

sudo systemctl restart pcscd

Additional Notes

The Defense Travel System no longer requires Oracle Java in order to function correctly.

If you have trouble with IcedTea See the instructions on SDB:Installing_Java to install.

If you have previously used the CACkey module for accessing the Defense Travel System and now use Coolkey, you will have to edit the configuration file:


Alter the line that contains the following information (/usr/lib64/ for 64bit and /usr/lib/ for 32bit):

<param name="pkcs11_library">/usr/lib64/</param>

It should reflect the coolkey module:

<param name="pkcs11_library">/usr/lib64/</param>

External Links

Team members

See also

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