How to get smartcards or crypto-tokens running on Debian Linux and Windows

This is a step-by-step Howto on installation and usage of the necessary commands to get smartcards or crypto-tokens working on Linux — and on Windows.
Smart card software on Linux consists of a driver for the card reader also called card terminal and a driver for the smartcard or token. There are two projects, OpenSC and MUSCLE. Both projects produce drivers for card terminals (for OpenSC this sub-project is called OpenCT) and for various cards. There are configuration options to make one project see the drivers of the other and vice versa.
I’m using OpenCT (card terminal) and OpenSC (smart card) software because these have worked better for me — except for the pcscd daemon from the MUSCLE project that might be needed for some applications. If you’re using software that depends on a PC/SC interface, you’ll also need to install the pcscd daemon (comes as a debian package).
Manufacturers are continuously improving their smartcards and the applications that run on the card. Up to now this has created an ever-changing pile of middleware to talk to these cards. An idea to improve the situation was a programmable card: Put a Java interpreter on the card and provide applets (so-called “cardlets”) for applications. The idea claims this would improve the situation for middleware on the host. Unfortunately this isn’t quite true: The Java virtual machine on smartcards is subject to change. So we have cards with a recent JVM and old cards with an ancient (1.1 from 2001) JVM. This means the applet needed to make the card work has to be cross-compiled to an older JVM depending on the card used. And there are still a number of host configuration issues.
The situation is worsened by the fact that many manufacturers of smartcards provide cards with their proprietary cardlet in the ROM of the card. This means these cards cannot be used with the applet that matches your middleware. And we’re back to the start and have to write a driver for the proprietary (this time java) middleware as before.
If you’re using Java-based smartcards you need to get a card that can accept a new applet and has the necessary developer keys published. Usually these cards are called “developer version” or similar. You then can use the MCardApplet from the MUSCLE plugins project. I recommend to build the applet yourself — after all this is a security application where your security depends on the software running on the card. There is a section below for preparing a java card with the appropriate applet.
I got the eToken PRO 32k (4.2B) working with OpenSC but not the eToken PRO 72k (Java). The first uses Siemens CardOS, the number in parentheses denotes the version number. Unfortunately these old CardOS based tokens will be discontinued, and Siemens seems to have announced end of life status for its CardOS.
The 72k eToken from Aladdin uses Java and needs a Java applet. The OpenSC project claims that the Java token works with OpenSC, but it didn’t for me. Maybe the token wasn’t a developer version that can accept an applet. The token also didn’t work under windows (although it worked with the Aladdin software there, i.e., I could initialize it) and I had a recent OpenSC binary release for windows from October 2009.
From the OpenSC documentation: “For programmable java cards: the support is for the card with the specific applet – if you have a different applet on your card, it might not be supported.”
First steps for non-Java cards or Java-cards with MCardApplet installed (for installation of the applet, see below):
Install smartcard software and card terminal framework:

apt-get install pcscd opensc libengine-pkcs11-openssl

The following NEW packages will be installed:
  libengine-pkcs11-openssl libp11-0

If your smartcard reader is not supported by pcscd, you should install the openct package in addition to the packages above. You can then run pcscd on top of openct.
After installing these programs, we need to configure pcscd to correctly use our reader. Configure /etc/opensc/opensc.conf to use the pcscd method, search for reader_drivers inside the app default stanza of the config file and modify this to:

reader_drivers = pcsc;

For CCID compatible readers without openct installed, the reader should be visible after plugging in the reader into the USB port:

Readers known about:
Nr.    Driver     Name
0      pcsc       Gemplus GemPC Key 00 00

If the card reader is not directly supported by pcscd (but is supported by openct) we need to configure /etc/reader.conf.d/openct, a config file of pcscd, to use OpenCT as the input method, for this the file should contain:

FRIENDLYNAME     “OpenCT”
DEVICENAME       /dev/null
LIBPATH          /usr/lib/openct-ifd.so
CHANNELID        0

after modifying this file on Debian (on non-Debian systems you’ll probably have to modify /etc/reader.conf directly) we have to run:

update-reader.conf

which creates a new /etc/reader.conf. Now stop and restart openct and pcscd in the following order:

/etc/init.d/pcscd stop
/etc/init.d/openct restart
/etc/init.d/pcscd start

When everything went OK, you should see a pcscd based reader using opensc-tool:

opensc-tool -l

Readers known about:
Nr.    Driver     Name
0      pcsc       OpenCT 00 00

Add user to “scard” group in /etc/group and log in again to have the permissions to access the card. This is necessary if you want to use a reader provided by openct without going through pcscd.
If all else fails, you can still use openct without pcscd and set reader_drivers in /etc/opensc/opensc.conf to:

reader_drivers = openct;

Then a reader should be visible like this:

opensc-tool -l

Readers known about:
Nr.    Driver     Name
0      openct     Aladdin eToken PRO 64k
1      openct     OpenCT reader (detached)
2      openct     OpenCT reader (detached)
3      openct     OpenCT reader (detached)
4      openct     OpenCT reader (detached)

Now we should be able to read the card, if there is only one token in the USB port and no other smartcard readers are installed, we can leave out the -r option (for specifying the reader to use):

cardos-info

3b:f2:18:00:02:c1:0a:31:fe:58:c8:09:75
Info : CardOS V4.2B (C) Siemens AG 1994-2005
Chip type: 123
Serial number: 27 37 c0 09 2b 18
Full prom dump:
33 66 00 45 CB CB CB CB 7B FF 27 37 C0 09 2B 18 3f.E….{.’7..+.
00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 …………….
OS Version: 200.9 (that’s CardOS M4.2b)
Current life cycle: 32 (administration)
Security Status of current DF:
Free memory : 1024
ATR Status: 0x0 ROM-ATR
Packages installed:
Ram size: 4, Eeprom size: 32, cpu type: 66, chip config: 63
Free eeprom memory: 27686
System keys: PackageLoadKey (version 0xfe, retries 10)
System keys: StartKey (version 0xff, retries 10)
Path to current DF:

1.   Using Java-based Smartcards
Java-based smartcards need some preparation to work with OpenSC. First you should make sure that you have a card that permits you to upload your own applet (cardlet) to the card. This usually means you need a so-called developer version. Avoid cards that have a proprietary manufacturer applet in read-only memory! You also usually need some development keys to upload a cardlet to the card.
For the following instructions I’ve used the Gemalto TOP IM FIPS CY2 (Cyberflex Access 64k v2) which is an old card that has a Java virtual machine version 1.1 from 2001 (!) but the card is well established and will probably be available for some time.
For the card reader I’ve used the Gemalto USB Shell V2 (GemPC Key), a CCID compatible reader. When buying a new reader, you should use one that follows the CCID specification from the PC/SC Workgroup, this ensures that OpenCT will support it. The card reader I’m using can read ID-000 format cards, also called SIM cards. These are small form-factor cards that are nice for authentication purposes. The Cyberflex card I’m using is available in ID-000. If a card isn’t available in ID-000, chances are you can make it fit using a service similar to this SIM cutting service.
Preparing the card for use with OpenSC is a two-step process. The first step is to obtain the necessary applet for the card. The second is to upload the applet to the card and initialize the card with a default PIN. Note that 2048 bit keys may not work with MCardApplet with the current software versions, see Some notes on key sizes.

1.1.   Obtaining the MCardApplet for your card
I recommend building your own version of the applet from source. Get the source code from svn://svn.debian.org/muscleplugins/trunk/MCardApplet using the source code control tool subversion:

svn co svn://svn.debian.org/muscleplugins/trunk/MCardApplet

I had to make several changes to use Java 1.6 for cross-building for the ancient Java VM that runs on the card. My Cflex.properties looks like this:

CARD_NAME=Cflex
JAVA_BUILD_HOME=/usr
JC_HOME=${basedir}/depends/jc212
API_JAR=${JC_HOME}/lib/api21.jar
API_EXPORT_FILES=${JC_HOME}/api21_export_files
CAPTRANS=${basedir}/depends/jc212/bin/captransf.jar
VM_SOURCE_VERSION=1.2
VM_TARGET_VERSION=1.1
BOOTCLASSPATH=${basedir}/depends/jdk1.2.2/depends/jdk1.2.2/lib

In particular, I’m using the native java environment installed on debian lenny. This lives in /usr. Otherwise you should follow the excellent building instructions in the file INSTALL. Then I’ve modified the javac in the target named compile in the common.xml ant build file as follows:

<target depends=”precompile” name=”compile”>
    <mkdir dir=”${OUTPUT_DIR}”/>
    <javac debug=”on”
        verbose=”on”
        fork=”true”
        executable=”${JAVA_BUILD_HOME}/bin/javac”
        srcdir=”${APPLET_SRC}”
        destdir=”${OUTPUT_DIR}”
        target=”${VM_TARGET_VERSION}”
        source=”${VM_SOURCE_VERSION}”>
        <bootclasspath>
            <pathelement location=”${BOOTCLASSPATH}”/>
        </bootclasspath>
        <classpath>
            <pathelement location=”${API_JAR}”/>
            <pathelement location=”.”/>
            <pathelement path=”${java.class.path}”/>
        </classpath>
    </javac>
</target>

I’ve added the target and source options. These refer to the specific java virtual machine version we’re cross-building for. I’ve also added the bootclasspath to get the classes that are VM specific from the old java development package.
This allows me to cross-build the applet for an old version of the java virtual machine without running the old java development environment which does no longer run on recent versions of Linux due to library incompatibilities.
I also had to change all the backslashes in common.xml to forward slashes. It looks like the java compiler can handle the backslashes in path names, but the other tools cannot.
Before building you should also look through CflexCapabilities.properties for any capabilities you want to enable which are not enabled in the default configuration. I had to enable -DWITH_RSA_2048 and -DWITH_SIGN for example.
For the impatiant I’m offering a pre-compiled version of the applet. I’ll update this text with the build instructions soon.

1.2.   Uploading the applet to the card
As a preparation for this step, you should install the pcsc daemon and the pcsclite development packages on debian:

apt-get install pcscd libpcsclite-dev

For uploading the applet to the card, I recommend using gpshell, a tool from the globalplatform project which depends on the globalplatform library. Unfortunately these are not yet packaged as Debian packages, so obtain the sourcecode to both, gpshell and the globalplatform library . Unpack these packages and build using the normal process:

./configure
make
make install

For the globalplatform library you need the development libraries for libpcsclite, available as the Debian package libpcsclite-dev which should be installed before the ./configure step above.
If you installed the globalplatform library without root privileges, you have to run ldconfig as root to make the new library available in the shared library cache.
Check that your smartcard services are running (see above for how to do that) and verify that you see your card reader (or token) using:

opensc-tool -l

The gpshell tool interfaces to the card via pcscd, so you should see something similar to the following:

Readers known about:
Nr.    Driver     Name
0      pcsc       Gemplus GemPC Key 00 00

Now we can proceed to upload the applet using gpshell. We need the following applet upload gpshell script, put this into the file applet_install.gpshell, note that lines terminated with “” need to be concatenated, gpshell currently doesn’t understand continuation lines:

enable_trace
establish_context
card_connect
select -AID a000000003000000
open_sc -security 1 -keyind 0 -keyver 0 
   -mac_key 404142434445464748494a4b4c4d4e4f 
   -enc_key 404142434445464748494a4b4c4d4e4f
delete -AID a00000000101
delete -AID a000000001
delete -AID a0000003230101
delete -AID a00000032301
install_for_load -pkgAID a000000001 -nvCodeLimit 16000 
   -sdAID a000000003000000
load -file CardEdgeCflex.ijc
install_for_install -instParam 00 -priv 02 -AID a00000000101 
   -pkgAID a000000001 -instAID a00000000101 -nvDataLimit 32000
card_disconnect
release_context

and run the script with gpshell:

gpshell applet_install.gpshell

Finally we will have to set a default PIN for the card using opensc-tool:

opensc-tool -s 00:A4:04:00:06:A0:00:00:00:01:01 -s 
B0:2A:00:00:38:08:4D:75:73:63:6C:65:30:30:04:01:08:
30:30:30:30:30:30:30:30:08:30:30:30:30:30:30:30:30:
05:02:08:30:30:30:30:30:30:30:30:08:30:30:30:30:30:
30:30:30:00:00:17:70:00:02:01

This sets the PIN to eight zeros, “00000000″. After this procedure the card can be used like a normal PKCS#15 based card with OpenSC.

1.2.1.   Some notes on using the gpshell script with other cards
Many of the magic numbers in the gpshell script depend on the card in use and on the applet that is uploaded. An AID is an applet-ID. The open_sc command has nothing to do with OpenSC, but opens a secure channel to the card. The parameters are the developer keys of the card. In our example, the key is used twice and the hex-bytes denote the string:

@ABCDEFGHIJKLMNO

The AID used for the secure channel is different for other brands of cards. I was able to find out this AID using the following AID gpshell script:

enable_trace
establish_context
card_connect
open_sc -security 1 -keyind 0 -keyver 0 
   -mac_key 404142434445464748494a4b4c4d4e4f 
   -enc_key 404142434445464748494a4b4c4d4e4f
get_status -element 80
card_disconnect
release_context

This displays for the Gemalto TOP IM FIPS CY2:

List of applets (AID state privileges)
a000000003000000        7       0

The delete commands remove older versions of the applet — there also was a version that had another applet ID — from the card before uploading the new version. Think of the applet living in a package named a000000001 and the applet named a00000000101. The install_for_load command establishes the package inside the a000000003000000 package. Then the install_for_install command installs the applet into non volatile memory after upload.
Note that these numbers are hard-coded into the applet that is being uploaded. This is defined during compile-time and for the MCardApplet this can be configured in the common.xml ant-file. When packaging the compiled java classes, the build process generates .cap files which contain the applet ID in binary format, notably the Applet.cap file contains the AID of the applet.
So if these numbers are changed when building a custom applet, be sure to adapt the upload commands, too. A warning here: All tools that depend on the MCardApplet expect the given AID, so changing the AID would incur a change of all tools or at least their configuration.

2.   OpenVPN Preparation: Step by step process with high-level tool
This section describes how to initialize a token, create a user key and certificate using tools that come with OpenVPN. This was only tested on Linux since the certificate handling scripts for OpenVPN are more advanced on Linux.
I had to patch the pkitool of OpenVPN to use the pkcs15-init command instead of the pkcs11-tool command for initializing the token and creating keys. The reason is that Aladdin limits their tokens to use one key for only one purpose (encryption or signing). The pkcs15-init command allows the specification of the key purpose while the pkcs11-tool command does not.
In the following we assume you are in the easy-rsa directory of OpenVPN, and you have initialized the configuration by reading the configuration in vars. It’s also always a good idea to have a backup of all the OpenVPN keys before starting.
Initializing the token for first use (or re-using an already formatted token) THIS DESTROYS ALL DATA ON THE TOKEN:

./pkitool –pkcs15-init 0 “Thomas Mustermann”

New User PIN.
Please enter User PIN:
Please type again to verify:
Unblock Code for New User PIN (Optional – press return for no PIN).
Please enter User unblocking PIN (PUK):
Please type again to verify:

If the token was already initialized, the procedure would also ask for the old password.
Now we can check that everything worked, by looking at the PINs:

pkcs15-tool –list-pins

Now we can proceed to generate a key pair and a certificate, this takes a long time:

./pkitool –pkcs15 /usr/lib/opensc-pkcs11.so 0 45 “user cert” client27

When everything went OK, we should be able to display keys, public keys, and certificates on the token:

pkcs15-tool –list-keys
pkcs15-tool –list-public-keys
pkcs15-tool –list-certificates

3.   What is needed for Windows
I’ve first installed the latest OpenVPN installer, only this package has the necessary TAP network driver for Linux. Only the TAP driver needs to be installed.
I’ve used a compiled version of OpenVPN that comes bundled with OpenSC from the binary windows repository, I’ve used the latest

opensc-i686-w32-mingw32-007-*.*

files (from Oct 2009). For 64bit Windows (AMD64) the

opensc-x86_64-pc-mingw32-003*.*

files should be used. Everything unpacked from these files should be installed to

C:ProgramsOpenVPN

I’ve also created a configuration directory under that directory called config. In config there are the necessary certificates (root ca) and hash keys and the client.ovpn configuration file.
When using my OpenVPN admin script, Python for windows from python.org and the Python WIN32 package are needed. In addition my rsclib library needs to be installed. For installing rsclib, unpack the .zip file and run:

setup.py install

from a command prompt. The admin script in pyovpn.zip has the same installation procedure.
After installing everything, basic working of the smart card can be verified with the OpenSC tools:

opensc-tool -l
cardos-info
pkcs15-tool –list-certificates

3.1.   Aladdin Token
For using the Aladdin eToken with Windows, the smart card tools of the manufacturer have to be installed — these include the driver for accessing the tokens. I’ve used:

PKIClient-x32-5.00.msi

from

eToken PKI Client 5.0 SP1 Windowsx32.zip

3.2.   Gemalto USB Shell Token V2
The driver for the Gemalto USB Shell Token reader can be downloaded free of charge from the Gemalto website.

4.   Using OpenVPN with SmartCard
OpenVPN uses a PKCS#11 provider library, on Debian this is /usr/lib/opensc-pkcs11.so, to access the smart card. We can show which certificates are on the card by issuing:

openvpn –show-pkcs11-ids /usr/lib/opensc-pkcs11.so

The following objects are available for use.
Each object shown below may be used as parameter to
–pkcs11-id option please remember to use single quote mark.

Certificate
      DN:             /C=AT/ST=AT/L=Weidling/ …
      Serial:         03
      Serialized id:  OpenSCx20Project/PKCSx20 …

Now OpenVPN can be started with the smartcard. I’m using the following additional config entries for OpenVPN — pkcs11-providers is set to the path of the PKCS#11 provider library:

pkcs11-providers “/usr/lib/opensc-pkcs11.so”
pkcs11-id-management
management 127.0.0.1 4711
management-query-passwords
management-hold

For Windows the provider library becomes (assuming the OpenSC tools where installed to C:ProgramsOpenVPNbin):

pkcs11-providers “C:\Programs\OpenVPN\bin\opensc-pkcs11.dll”

The other parameters are the same as for other operating systems.
Note also that the askpass option of OpenVPN does not work for querying the token password. In my experiment I had to give the token password to OpenVPN via the management interface using the config option management-query-passwords.
This configuration tells OpenVPN to open the management interface on Port 4711 of localhost. It will ask for the passphrase of the Aladdin token on that port. Additionally we wait (management-hold) until a management program has opened the management interface and told OpenVPN to proceed.
The pkcs11-id-management tells OpenVPN to accept the pkcs11-id to use via the management interface. With a little intelligence in the management interface we can avoid having the pkcs11-id in the configuration file (which would then be different for each user).
OpenVPN can be asked via the management interface about a listing of all pkcs11-ids. If there is only one certificate on the card, we feed the id of the only certificate back to OpenVPN when it asks about the pkcs11-id. This can be done without user intervention.
Unfortunately the feature that OpenVPN can ask the smartcard for all the certificates depends on the Token being present when OpenVPN is started. An alternative is to specify the pkcs11-id` directly in the configuration file. If this is specified, the management interface will ask for the token if it isn’t present when starting OpenVPN. The parameter to the pkcs11-id config parameter is the Serialized id from the command output above.
Since I have not found any graphical user interface programs for OpenVPN that can deal with asking the user for the token passphrase, I’ve written a little command-line python script which can be run on both, Windows and Linux, and will ask the user to insert the token and specify the token passphrase.
OpenVPN can be started with the script by issuing the command:

pyovpn

in a command prompt window. The command will start openvpn and proceed to ask for necessary token passwords.

4.1.   Low-level usage of the management interface
With the management-query-passwords option, OpenVPN will ask the password from the management interface. After starting the OpenVPN daemon and connnecting to the managment interface on the defined port (e.g., using telnet) we see the following message:

>INFO:OpenVPN Management Interface Version 1 — type ‘help’ for more info
>PASSWORD:Need ‘OpenSC Card (New User) token’ password

The password can then be entered using the password command of the managment interface:

password ‘OpenSC Card (New User) token’ sehrgeheimespasswort

OpenVPN answers with:

SUCCESS: ‘OpenSC Card (New User) token’ password entered, but not yet verified

5.   Key Revocation
Revoke a certificate:

openssl ca  -config $KEY_CONFIG -revoke keys/02.pem

(re-) generate key revocation list (CRL):

openssl ca  -config $KEY_CONFIG -gencrl -out keys/crl.pem

6.   OpenVPN Preparation: Step by step process with low-level tools
This section describes the low-level tools as used by the patched pkitool from OpenVPN. It does not create a certificate with OpenSSL. This is for documentation purposes only (to understand what goes on behind the scenes) and was my first approach to getting started with OpenSC.

• Erase the card — if you already have a Security Officer PIN installed, you need this for erasing the card:

  
  pkcs15-init -E
  

• Create PKCS#15 structure (option –no-so-pin specified not to create security officer PIN and user PUK) on the card — note that the keys need to be between 6 and 8 characters long and should be numeric if you intend to use a keypad for key-entry (which applies mostly to smartcards not to USB tokens). Also note that if you omit –no-so-pin you should keep the Security Officer PIN secure — only with it can the token be re-formatted:

  
  pkcs15-init –create-pkcs15 –no-so-pin
  

  New Security Officer PIN (Optional – press return for no PIN).
  Please enter Security Officer PIN:
  Please type again to verify:
  Unblock Code for New User PIN (Optional – press return for no PIN).
  Please enter User unblocking PIN (PUK):
  Please type again to verify:
  

• The steps above can be rolled into one command:

  
  pkcs15-init -E –create-pkcs15 –no-so-pin
  

• Add an authentication (user) ID to the token with corresponding PIN and PUK:

  
  pkcs15-init –store-pin –auth-id 01 –label “User Name”
  

  New User PIN.
  Please enter User PIN:
  Please type again to verify:
  Unblock Code for New User PIN (Optional – press return for no PIN).
  Please enter User unblocking PIN (PUK):
  Please type again to verify:
  

• Check that everything worked, by looking at the PINs:

  
  pkcs15-tool –list-pins
  

  PIN [Security Officer PIN]
      Com. Flags: 0x3
      ID        : ff
      Flags     : [0xB2], local, initialized, needs-padding, soPin
      Length    : min_len:6, max_len:8, stored_len:8
      Pad char  : 0x00
      Reference : 1
      Type      : ascii-numeric
      Path      : 3f005015
  
  PIN [User Name]
      Com. Flags: 0x3
      ID        : 01
      Flags     : [0x32], local, initialized, needs-padding
      Length    : min_len:4, max_len:8, stored_len:8
      Pad char  : 0x00
      Reference : 3
      Type      : ascii-numeric
      Path      : 3f005015
  

• Now we can generate an RSA key on the card. Note that we could also import a PKCS-12 key onto the card, but the more secure option is to let the card generate the key (so the key will never be available outside the card). The split-key option actually generates two key-pairs, one for encryption and one for signing. There are some labelling options to attach names to the generated keys but these aren’t needed if you want only one key. You could specify an application profile with the –id option, if this isn’t given the default ID 45 (authentication purposes) is used. The command will ask for the Security officer PIN, then for the User PIN, then again for the Security officer PIN (!):

  
  pkcs15-init –generate-key rsa/2048 –auth-id 01 –split-key
  

  Note that with Java smartcards the keysize 2048 might not work with the current version of the tools, see Some notes on key sizes.

• Now we can verify that the key was actually stored on the card:

  
  pkcs15-tool –list-keys
  

  Private RSA Key [Private Key]
      Com. Flags  : 3
      Usage       : [0x4], sign
      Access Flags: [0x1D], sensitive, alwaysSensitive, neverExtract, local
      ModLength   : 2048
      Key ref     : 16
      Native      : yes
      Path        : 3f005015
      Auth ID     : 01
      ID          : 45
  

• List public keys:

  
  pkcs15-tool –list-public-keys
  

  Public RSA Key [Public Key]
      Com. Flags  : 2
      Usage       : [0x4], sign
      Access Flags: [0x0]
      ModLength   : 2048
      Key ref     : 0
      Native      : no
      Path        : 3f0050153048
      Auth ID     :
      ID          : 45
  

• For the following steps we will need a minimum openssl config file:

  
  openssl_conf            = openssl_init
  
  [ openssl_init ]
  engines                 = engine_section
  
  [ req ]
  default_bits            = 2048
  default_keyfile         = privkey.pem
  distinguished_name      = req_distinguished_name
  
  [ req_distinguished_name ]
  countryName                     = Country Name (2 letter code)
  countryName_default             = AT
  countryName_min                 = 2
  countryName_max                 = 2
  stateOrProvinceName             = State or Province Name (full name)
  stateOrProvinceName_default     = Austria
  localityName                    = Locality Name (eg, city)
  localityName_default            = Vienna
  0.organizationName              = Organization Name (eg, company)
  0.organizationName_default      = example.com
  organizationalUnitName          = Organizational Unit Name (eg, section)
  organizationalUnitName_default  = IT-Department
  commonName                      = Common Name (eg, server’s hostname)
  commonName_max                  = 64
  emailAddress                    = Email Address
  emailAddress_max                = 40
  
  [ engine_section ]
  pkcs11 = pkcs11_section
  
  [ pkcs11_section ]
  engine_id = pkcs11
  dynamic_path = /usr/lib/engines/engine_pkcs11.so
  MODULE_PATH = /usr/lib/opensc-pkcs11.so
  init = 0
  

• Generate a certificate request (CSR) from this key using openssl:

  
  CLIENT=newclient
  openssl req -days 3650 -new -out $CLIENT.csr -config openssl.cnf 
    -engine pkcs11 -keyform engine -key 0:45 -sha1
  

  This will ask for all the certificate parameters. Alternatively these can be specified using the -subj option of openssl (this is broken into several lines but should be assembled into one line) with the following parameter:

  /C=AT/ST=Austria/L=Vienna/O=example.com/OU=IT-Department
  /CN=$CLIENT/emailAddress=user@example.com
  

• You can view the contents of the CSR using:

  
  openssl req -in $CLIENT.csr -noout -text
  

• Now sign the certificate request with whatever tools you are using. With the pkitool of OpenVPN this would become (after having copied the certificate request newclient.csr to the keys directory):

  
  pkitool –sign newclient
  

  The message about not being able to access newclient.key can be ignored.

• You may want to delete old certificates from the token:

  
  pkcs15-init –delete-objects cert –id=45
  

• Then import the new certificate onto the token:

  
  pkcs15-init –store-certificate newclient.crt –id=45
  

• Reading a certificate from the token and output with openssl:

  
  pkcs15-tool –read-certificate 45 | openssl x509 -noout -text
  

6.1.   Some notes on key sizes
Using 2048 bit keys should generally be possible with newer cards. I had some problems with these key sizes using my Java smartcard, though.
After uploading the applet to the card, it is possible to create a key with either 1024 or 2048 bit. This indicates that the card is able to handle the large keysize. When trying to generate a CSR using openssl the command failed with:

[opensc-pkcs11] iso7816.c:99:iso7816_check_sw: No precise diagnosis
[opensc-pkcs11] muscle.c:745:msc_compute_crypt_process: returning with:
                Card command failed
[opensc-pkcs11] muscle.c:840:msc_compute_crypt: returning with:
                Card command failed
[opensc-pkcs11] card-muscle.c:749:muscle_compute_signature:
                Card signature failed: Card command failed
[opensc-pkcs11] sec.c:53:sc_compute_signature: returning with:
                Card command failed
[opensc-pkcs11] pkcs15-sec.c:273:sc_pkcs15_compute_signature:
                sc_compute_signature() failed: Card command failed
20808:error:0E06D06C:configuration file routines:NCONF_get_string:no value:
conf_lib.c:329:group=req_attributes name=unstructuredName_min
20808:error:0E06D06C:configuration file routines:NCONF_get_string:no value:
conf_lib.c:329:group=req_attributes name=unstructuredName_max
20808:error:8000A005:Vendor defined:PKCS11_rsa_sign:General Error:
p11_ops.c:97:
20808:error:0D0C3006:asn1 encoding routines:ASN1_item_sign:EVP lib:
a_sign.c:276:

Worse, after reinitializing the card in this state with:

pkcs15-init -E –create-pkcs15 –no-so-pin
pkcs15-init –store-pin –auth-id 01 –label “User Name”

and trying to generate a smaller key, this fails with:

pkcs15-init –generate-key rsa/1024 –auth-id 01 –split-key

[pkcs15-init] iso7816.c:102:iso7816_check_sw: Unknown SWs; SW1=9C, SW2=03
[pkcs15-init] muscle.c:557:msc_generate_keypair: returning with:
              Card command failed
[pkcs15-init] card.c:678:sc_card_ctl: returning with:
              Card command failed
[pkcs15-init] pkcs15-muscle.c:272:muscle_generate_key:
              Unable to generate key
[pkcs15-init] pkcs15-muscle.c:273:muscle_generate_key: returning with:
              Card command failed
Failed to generate key: Card command failed

I was able to fix this by re-downloading the applet onto the card. This also happens the other way round, when generating a 1024 bit key first and trying — after reinitializing the card with pkcs15-init — to generate a 2048 bit key.
So I recommend to stick with 1024 bit keys with the current software versions (debian lenny).