opensc.conf - Man Page

configuration file for OpenSC


OpenSC obtains configuration data from the following sources in the following order

  1. command-line options
  2. environment variables
  3. Windows registry key in HKEY_CURRENT_USER (if available)
  4. Windows registry key in HKEY_LOCAL_MACHINE (if available)
  5. system-wide configuration file (/etc/opensc.conf)

The configuration file, opensc.conf, is composed of blocks, which, in general, have the following format:

key [, name...] {

block_contents is one or more block_items where a block_item is one of

At the root level, opensc.conf should contain one or more application specific configuration blocks:

app application {

application specifies one of:

Configuration Options

debug = num;

Amount of debug info to print (Default: 0). A greater value means more debug info.

The environment variable OPENSC_DEBUG overwrites this setting.

debug_file = filename;

The file to which debug output will be written (Default: stderr). Special values stdout and stderr are recognized.

profile_dir = filename;

PKCS#15 initialization/personalization profiles directory for pkcs15-init(1) (Default: /usr/share/opensc).

If this configuration value is not found on Windows, the registry key Software\OpenSC Project\OpenSC\ProfileDir is checked.

disable_colors = bool;

Disable colors of log messages (Default: false if attached to a console, true otherwise).

disable_popups = bool;

Disable pop-ups of built-in GUI (Default: false).

enable_default_driver = bool;

Enable default card driver (Default: false). Default card driver is explicitly enabled for opensc-explorer(1) and opensc-tool(1)

card_drivers = name...;

Allowlist of card drivers to load at start-up. The special value internal (the default) will load all statically linked drivers.

If an unknown (i.e. not internal or old) driver is supplied, a separate configuration block has to be written for the driver. A special value old will load all statically linked drivers that may be removed in the future.

The list of supported card driver names can be retrieved from the output of opensc-tool --list-drivers.

The environment variable OPENSC_DRIVER overwrites this setting.

ignored_readers = name...;

List of readers to ignore (Default: empty). If any of the comma separated strings listed is matched in a reader name (case sensitive, partial matching possible), the reader is ignored by OpenSC. Use opensc-tool --list-readers to see all currently connected readers.

reader_driver name { block_contents }

Configuration of the smart card reader driver where name is one of:

  • ctapi: See the section called “Configuration of CT-API Readers”
  • pcsc: See the section called “Configuration of PC/SC Readers”
  • openct: See the section called “Configuration of OpenCT Readers”
  • cryptotokenkit: Configuration block for CryptoTokenKit readers

See the section called “Configuration of Smart Card Reader Driver”.

card_driver name { block_contents }

Configuration of the card driver where name is one of:

  • npa: See the section called “Configuration Options for German ID Card”
  • dnie: See the section called “Configuration Options for DNIe”
  • edo: See the section called “Configuration Options for Polish eID Card”
  • myeid: See the section called “Configuration Options for MyEID Card”
  • Any other value: Configuration block for an externally loaded card driver
card_atr hexstring { block_contents }

In addition to the built-in list of known cards in the card driver, you can configure a new card for the driver using the card_atr block.

For details see the section called “Configuration based on ATR”.

secure_messaging name { block_contents }

Configuration options for the secure messaging profile name:

module_name = filename;

Name of external SM module (Default:

module_path = filename;

Directory with external SM module (Default: /usr/lib64).

If this configuration value is not found on Windows, the registry key Software\OpenSC Project\OpenSC\SmDir is checked.

module_data = value;

Specific data to tune the module initialization.

mode = value;

Secure messaging mode. Known parameters:

  • transmit: In this mode the procedure to securize an APDU is called by the OpenSC general APDU transmit procedure. In this mode all APDUs, except the ones filtered by the card specific procedure, are securized.
  • acl: In this mode APDU are securized only if needed by the ACLs of the command to be executed.
flags = value;

Secure messaging type specific flags.

kmc = hexstring;

Default KMC of the GP Card Manager for the Oberthur's Java cards.

ifd_serial = hexstring;

keyset[_aid]_num_enc = value; keyset[_aid]_num_mac = value;

Keyset values from IAM profiles of the Gemalto IAS/ECC cards with an optional application identifier

framework name { block_contents }

Internal configuration options where name is one of:

  • pkcs15: See the section called “Configuration of PKCS#15 Framework”
  • tokend: See the section called “Configuration of Tokend”
pkcs11 { block_contents }

Parameters for the OpenSC PKCS11 module.

For details see the section called “Configuration of PKCS#11”.

Configuration of Smart Card Reader Driver

Configuration Options for all Reader Drivers

max_send_size = num; max_recv_size = num;

Limit command and response sizes (Default: max_send_size = 255, max_recv_size = 256) . Some Readers don't propagate their transceive capabilities correctly. max_send_size and max_recv_size allow setting the limits manually, for example to enable extended length capabilities.

enable_escape bool;

Detect reader capabilities with escape commands (wrapped APDUs with CLA=0xFF as defined by PC/SC pt. 3 and BSI TR-03119, e.g. for getting the UID, escaped PIN commands and the reader's firmware version, Default: false)

Configuration of CT-API Readers

module filename { ports = nums; }

Load the specified CT-API module with the specified number of ports.

Configuration of PC/SC Readers

connect_exclusive = bool;

Connect to reader in exclusive mode (Default: false)? This option has no effect in Windows' minidriver.

disconnect_action = action;

What to do when disconnecting from a card (SCardDisconnect). Valid values are leave, reset, unpower (Default: leave). This option has no effect in Windows' minidriver.

transaction_end_action = action;

What to do at the end of a transaction (SCardEndTransaction). Valid values are leave, reset, unpower (Default: leave). This option has no effect in Windows' minidriver.

reconnect_action = action;

What to do when reconnection to a card (SCardReconnect). Valid values are leave, reset, unpower (Default: leave). This option has no effect in Windows' minidriver.

enable_pinpad = bool;

Enable pinpad if detected (PC/SC v2.0.2 Part 10, Default: true)

fixed_pinlength = num;

Some pinpad readers can only handle one exact length of the PIN. fixed_pinlength sets this value so that OpenSC expands the padding to this length (Default: 0, i.e. not fixed).

provider_library = filename;

Use specific PC/SC provider (Default:

Configuration of OpenCT Readers

readers = num;

Virtual readers to allocate (Default: 2).

Configuration Options for MyEID Card

disable_hw_pkcs1_padding = bool;

The MyEID card can internally encapsulate the data (hash code) into a DigestInfo ASN.1 structure according to the selected hash algorithm (currently only for SHA1). DigestInfo is padded to RSA key modulus length according to PKCS#1 v1.5, block type 01h. Size of the DigestInfo must not exceed 40% of the RSA key modulus length. If this limit is unsatisfactory (for example someone needs RSA 1024 with SHA512), the user can disable this feature. In this case, the card driver will do everything necessary before sending the data (hash code) to the card.

Configuration Options for German ID Card

can = value;

German ID card requires the CAN to be verified before QES PIN. This, however, is not part of the PKCS#15 profile of the card. So for verifying the QES PIN we actually need both. The CAN may be given here. If the CAN is not given here, it will be prompted on the command line or on the reader (depending on the reader's capabilities).

st_dv_certificate = filename; st_certificate = filename; st_key = filename;

QES is only possible with a Comfort Reader (CAT-K), which holds a cryptographic key to authenticate itself as signature terminal (ST). We usually will use the reader's capability to sign the data. However, during development you may specify soft certificates and keys for a ST.

An example PKI can be found in the example data for the German ID card emulator[1]

Configuration Options for DNIe

user_consent_enabled = bool;

Configure the warning message when performing a signature operation with the DNIe. Only used if compiled with --enable-dnie-ui

user_consent_app = filename;

Specify the pinentry application to use if warning is configured to be displayed using pinentry (Default: /usr/bin/pinentry). Only used if compiled with --enable-dnie-ui

Configuration Options for Polish eID Card

can = value;

CAN (Card Access Number – 6 digit number printed on the right bottom corner of the front side of the document) is required to establish connection with the card. It might be overwritten by EDO_CAN environment variable. Currently, it is not possible to set it in any other way.

Configuration based on ATR

atrmask = hexstring;

The mask is logically AND'd with an card ATR prior to comparison with the ATR reference value above. Using this mask allows identifying and configuring multiple ATRs as the same card model.

driver = name;

When enabled, overrides all possible settings from the card drivers built-in card configuration list.

name = name;

Set card name for card drivers that allows it.

type = num;

Allows setting the exact type of the card internally used by the card driver. Allowed values can be found in the source code of cards.h.

flags = value...;

Card flags as an hex value. Multiple values are OR'd together. Depending on card driver, this allows fine-tuning the capabilities in the card driver for your card.

Optionally, some known parameters can be specified as strings:

  • rng: On-board random number source
  • keep_alive: Request the card driver to send a "keep alive" command before each transaction to make sure that the required applet is still selected.
pkcs15emu = name;

When using PKCS#15 emulation, force the emulation driver for specific cards. Required for external drivers, but can be used with built-in drivers, too.

force_protocol = value;

Force protocol selection for specific cards. Known parameters:

  • t0
  • t1
  • raw
read_only = bool;

Mark card as read/only card in PKCS#11/Minidriver/BaseCSP interface (Default: false).

md_supports_X509_enrollment = bool;

Indicate X509 enrollment support at Minidriver/BaseCSP interface (Default: false).

md_guid_as_id = bool;

Use the GUID generated for the key as id in the PKCS#15 structure (Default: false, i.e. auto generated)

md_guid_as_label = bool;

Use the GUID generated for the key as label in the PKCS#15 structure (Default: false, i.e. no label set).

md_supports_container_key_gen = bool;

Card allows generating key pairs on the card (Default: false).

md_supports_container_key_import = bool;

Card allows importing private keys (Default: false).

md_pinpad_dlg_title = value;

Window title of the PIN pad dialog (Default: "Windows Security").

md_pinpad_dlg_icon = filename;

Filename of the icon for the PIN pad dialog; use "" for no icon (Default: Built-in smart card icon).

md_pinpad_dlg_main = value;

Main instruction of the PIN pad dialog (Default: "OpenSC Smart Card Provider").

md_pinpad_dlg_content_user = value;

Content of the PIN pad dialog for role "user" (Default: "Please enter your PIN on the PIN pad.").

md_pinpad_dlg_content_user_sign = value;

Content of the PIN pad dialog for role "user+signature" (Default: "Please enter your digital signature PIN on the PIN pad.").

md_pinpad_dlg_content_admin = value;

Content of the PIN pad dialog for role "admin" (Default: "Please enter your PIN to unblock the user PIN on the PIN pad.")

md_pinpad_dlg_expanded = value;

Expanded information of the PIN pad dialog (Default: "This window will be closed automatically after the PIN has been submitted on the PIN pad (timeout typically after 30 seconds).")

md_pinpad_dlg_enable_cancel = bool;

Allow the user to cancel the PIN pad dialog (Default: false). If this value is set to true, the user needs to click "OK" to start the PIN verification on the PIN pad. The user can choose the default behavior by enabling or disabling the checkbox of the dialog. The setting is saved by the program's full path (program_path) that uses OpenSC.

The registry key HKCU\Software\OpenSC Project\OpenSC\md_pinpad_dlg_enable_cancel\program_path overwrites this setting with a DWORD set to either 1 (enabled) or 0 (disabled).

md_pinpad_dlg_timeout = num;

Time in seconds for the progress bar of the PIN pad dialog to tick. 0 removes the progress bar (Default: 30).

notify_card_inserted = value; notify_card_inserted_text = value;

Notification title and text when card was inserted (Default: "Smart card detected", ATR of the card).

notify_card_removed = value; notify_card_removed_text = value;

Notification title and text when card was removed (Default: "Smart card removed", name of smart card reader).

notify_pin_good = value; notify_pin_good_text = value;

Notification title and text when PIN was verified (Default: "PIN verified", "Smart card is unlocked").

notify_pin_bad = value; notify_pin_bad_text = value;

Notification title and text when PIN was wrong (Default: "PIN not verified", "Smart card is locked").

Configuration of PKCS#15 Framework

use_file_caching = bool;

Whether to cache the card's files (e.g. certificates) on disk in file_cache_dir. Possible parameters:

  • yes: Cache all files (public and private).

public: Cache only public files.


no: File caching disabled.


(Default: no).

If caching is done by a system process, the cached files may be placed inaccessible from the user account. Use a globally readable and writable location if you wish to share the cached information. Note that the cached files may contain personal data such as name and mail address.

file_cache_dir = filename;

Where to cache the card's files. The default values are:

  • $XDG_CACHE_HOME/opensc/ (If $XDG_CACHE_HOME is defined)
  • $HOME/.cache/opensc/ (Unix)
  • $USERPROFILE\.eid-cache\ (Windows)

If caching is done by a system process, the cached files may be placed inaccessible from a user account. Use a globally readable and writable location if you wish to share the cached information. Note that the cached files may contain personal data such as name and mail address.

use_pin_caching = bool;

Use PIN caching (Default: true)?

pin_cache_counter = num;

How many times to use a PIN from cache before re-authenticating it (Default: 10)?

pin_cache_ignore_user_consent = bool;

Older PKCS#11 applications not supporting CKA_ALWAYS_AUTHENTICATE may need to set this to get signatures to work with some cards (Default: false).

It is recommended to enable also PIN caching using use_pin_caching option for OpenSC to be able to provide PIN for the card when needed.

private_certificate = value;

How to handle a PIN-protected certificate. Known parameters:

  • protect: The certificate stays PIN-protected.
  • declassify: Allow reading the certificate without enforcing verification of the PIN.
  • ignore: Ignore PIN-protected certificates.

(Default: ignore in Tokend, protect otherwise).

enable_pkcs15_emulation = bool;

Enable pkcs15 emulation (Default: true).

try_emulation_first = bool;

Prefer pkcs15 emulation code before the normal pkcs15 processing (Default: no). Some cards work in emu-only mode, and do not depend on this option.

enable_builtin_emulation = bool;

Enable builtin emulators (Default: true).

builtin_emulators = emulators;

List of the builtin pkcs15 emulators to test (Default: internal)

Special value of internal will try all not disabled builtin pkcs15 emulators.

Special value of old will try all disabled pkcs15 emulators.

pkcs11_enable_InitToken = bool;

Enable initialization and card recognition (Default: false).

emulate name { block_contents }

Configuration options for a PKCS#15 emulator where name is a short name for an external card driver.

module = filename;

For pkcs15 emulators loaded from an external shared library/DLL, you need to specify the path name of the module and customize the card_atr example above correctly.

function = name;

Get the init function name of the emulator (Default: sc_pkcs15_init_func_ex)

application hexstring { block_contents }

Configuration of the on-card-application where hexstring is the application identifier (AID).

type = name;

Type of application where name is one of:

  • generic
  • protected

Used to distinguish the common access application and application for which authentication to perform some operation cannot be obtained with the common procedures (ex. object creation protected by secure messaging). Used by PKCS#11 module configured to expose restricted number of slots. (for ex. configured to expose only User PIN slot, User and Sign PINs slots, ...)

model = name;

disable = bool;

Do not expose application in PKCS#15 framework (Default: false)

Configuration of Tokend

score = num;

Score for OpenSC.tokend (Default: 300). The tokend with the highest score shall be used.

Configuration of PKCS#11

max_virtual_slots = num;

Maximum Number of virtual slots (Default: 16). If there are more slots than defined here, the remaining slots will be hidden from PKCS#11.

slots_per_card = num;

Maximum number of slots per smart card (Default: 4). If the card has fewer keys than defined here, the remaining number of slots will be empty.

lock_login = bool;

By default, the OpenSC PKCS#11 module will not lock your card once you authenticate to the card via C_Login (Default: false). Thus the other users or other applications is not prevented from connecting to the card and perform crypto operations (which may be possible because you have already authenticated with the card). This setting is not very secure.

Also, if your card is not locked, you can enconter problems due to limitation of the OpenSC framework, that still is not thoroughly tested in the multi threads environment.

Your settings will be more secure if you choose to lock your card. Nevertheless this behavior is a known violation of PKCS#11 specification. Now once one application has started using your card with C_Login, no other application can use it, until the first is done and calls C_Logout or C_Finalize. In the case of many PKCS#11 application this does not happen until you exit the application.

Thus it is impossible to use several smart card aware applications at the same time, e.g. you cannot run both Firefox and Thunderbird at the same time, if both are configured to use your smart card.

atomic = bool;

By default, interacting with the OpenSC PKCS#11 module may change the state of the token, e.g. whether a user is logged in or not (Default: false).

Thus other users or other applications may change or use the state of the token unknowingly. Other applications may create signatures abusing an existing login or they may logout unnoticed.

With this setting enabled the login state of the token is tracked and cached (including the PIN). Every transaction is preceded by restoring the login state. After every transaction a logout is performed. This setting by default also enables lock_login to disable access for other applications during the atomic transactions.

Please note that any PIN-pad should be disabled (see enable_pinpad), because the user would have to input his PIN for every transaction.

init_sloppy = bool;

With this setting disabled, the OpenSC PKCS#11 module will initialize the slots available when the application calls C_GetSlotList. With this setting enabled, the slots will also get initialized when C_GetSlotInfo is called (Default: true).

This setting is a workaround for Java which does not call C_GetSlotList when configured with a static slot instead of slotListIndex.

user_pin_unblock_style = mode;

User PIN unblock style mode is one of:

  • none (Default): PIN unblock is not possible with PKCS#11 API
  • set_pin_in_unlogged_session: C_SetPIN in unlogged session: PUK is passed as the OldPin argument of the C_SetPIN call.
  • set_pin_in_specific_context: C_SetPIN in the CKU_SPECIFIC_CONTEXT logged session: PUK is passed as the OldPin argument of the C_SetPIN call.
  • init_pin_in_so_session: C_InitPIN in CKU_SO logged session: User PIN 'UNBLOCK' is protected by SOPIN. (PUK == SOPIN).
create_puk_slot = bool;

Create slot for unblocking PIN with PUK (Default: false). This way PKCS#11 API can be used to login with PUK and change a PIN. May cause problems with some applications like Firefox and Thunderbird.

create_slots_for_pins = mode...;

Symbolic names of PINs for which slots are created where mode is a list of:

  • all (Default): All non-SO-PIN, non-unblocking PINs
  • user: The first global or first local PIN
  • sign: The second PIN (first local, second global or second local)

Card can contain more then one PINs or more then one on-card application with its own PINs. Normally, to access all of them with the PKCS#11 API a slot has to be created for all of them. Many slots could be annoying for some of widely used application, like FireFox. This configuration parameter allows to select the PIN(s) for which PKCS#11 slot will be created.

Only PINs initialised, non-SO-PIN, non-unblocking are associated with symbolic name.

For the module to simulate the opensc-onepin module behavior the following option create_slots_for_pins = "user";



Filename for a user defined configuration file

If this environment variable is not found on Windows, the registry key Software\OpenSC Project\OpenSC\ConfigFile is checked.


See debug = num;


See card_drivers = name...;


Write minidriver debug information to C:\tmp\md.log, if set to 1.

If this environment variable is not found on Windows, the registry key Software\OpenSC Project\OpenSC\MiniDriverDebug is checked.


PIV configuration during initialization with piv-tool.



System-wide configuration file


Extended example configuration file



German ID card emulator

Referenced By


08/08/2023 OpenSC File Formats