OpenSC supports the Cryptoflex cards beginning with version 0.5.0.

Cryptoflex specific features can be tested with cryptoflex-tool.
Due to the publicly available datasheets, cryptoflex-tool also includes
a PKCS #15 structure generator. At the moment all the encoded information
is hardcoded in the source file, but editing the structures should
be pretty straightforward.

Here are the steps to PKCS #15 structure generation:

WARNING: You should be using a very safe terminal when issuing the
         following commands.

0.  If you don't have a Cryptoflex 16k, you will have to add the ATR of
    your card manually to the flex_atrs structure at the top of card-flex.c.
    The ATR can be found with 'opensc-tool -a' command.

1.  Verify the AAK key and CHV2:

$ opensc-explorer
OpenSC Explorer version 0.5.0
Connecting to card in reader Towitoko Chipdrive Micro 0 0...
Using card driver: Schlumberger Multiflex/Cryptoflex
OpenSC [3F00]> ver KEY1 01:02:03:04:05:06:07:08		# replace these
Code correct.
OpenSC [3F00]> ver CHV2 31:32:33:34:00:00:00:00		# with your own values
Code correct.

2.  Create the CHV2 file, if not present:

$ cryptoflex-tool -P 2
Connecting to card in reader Towitoko Chipdrive Micro 0 0...
Using card driver: Schlumberger Multiflex/Cryptoflex
Please enter CHV2: 1234
Please enter PUK for CHV2: 12345678

3.  Create the PKCS #15 structure

$ cryptoflex-tool -C
Connecting to card in reader Towitoko Chipdrive Micro 0 0...
Using card driver: Schlumberger Multiflex/Cryptoflex
Please enter CHV1 (key 1): 1234
Please enter PUK for CHV1 (key 1): 12345678
Please enter CHV1 (key 2): 5678
Please enter PUK for CHV1 (key 2): 12345678

4.  Generate two 1024-bit RSA key pairs with openssl:

$ openssl genrsa -out key1.pem 1024
Generating RSA private key, 1024 bit long modulus
...........++++++
...++++++
e is 65537 (0x10001)
$ openssl genrsa -out key2.pem 1024
Generating RSA private key, 1024 bit long modulus
.....................++++++
....++++++
e is 65537 (0x10001)

5.  Create the files to hold the keys on the card:

$ cryptoflex-tool -a 5015 -c 1
$ cryptoflex-tool -a 4b02 -c 1

6.  Store the key pairs on the card:

$ cryptoflex-tool -a 5015 -p key1.pem -s -v  # (enter CHV1 for key 1)
$ cryptoflex-tool -a 4b02 -p key2.pem -s -v  # (enter CHV1 for key 2)

6a. Check if the keys are working:

$ pkcs15-crypt -i <plaintext-file> -o <signed-data> -s --pkcs1
Connecting to card in reader Towitoko Chipdrive Micro 0 0...
Trying to find a PKCS#15 compatible card...
Found OpenSC Test Card!
Enter PIN [Authentication PIN]: 
PIN code correct.

7.  Create two certificates with openssl. Name them cert1.crt and cert2.crt.This process is not in the scope
    of this document.

8.  Store the DER-encoded certificates on the card (this process will be
    automated in the future):

$ opensc-explorer
OpenSC Explorer version 0.5.0
Connecting to card in reader Towitoko Chipdrive Micro 0 0...
Using card driver: Schlumberger Multiflex/Cryptoflex
OpenSC [3F00]> cd 5015
OpenSC [3F00/5015]> create 4301 <size of cert1.crt>
OpenSC [3F00/5015]> create 4302 <size of cert2.crt>
OpenSC [3F00/5015]> put 4301 cert1.crt
OpenSC [3F00/5015]> put 4302 cert2.crt