Section: OpenSC Tools (1)
Updated: 02/25/2021
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pkcs11-tool - utility for managing and using PKCS #11 security tokens  


pkcs11-tool [OPTIONS]


The pkcs11-tool utility is used to manage the data objects on smart cards and similar PKCS #11 security tokens. Users can list and read PINs, keys and certificates stored on the token. User PIN authentication is performed for those operations that require it.  


--attr-from filename

Extract information from filename (DER-encoded certificate file) and create the corresponding attributes when writing an object to the token. Example: the certificate subject name is used to create the CKA_SUBJECT attribute.

--change-pin, -c

Change the user PIN on the token


Unlock User PIN (without --login unlock in logged in session; otherwise --login-type has to be 'context-specific').

--hash, -h

Hash some data.

--hash-algorithm mechanism

Specify hash algorithm used with RSA-PKCS-PSS signature or RSA-OAEP decryption. Allowed values are "SHA-1", "SHA256", "SHA384", "SHA512", and some tokens may also allow "SHA224". Default is "SHA-1".

Note that the input to RSA-PKCS-PSS has to be of the size equal to the specified hash algorithm. E.g., for SHA256 the signature input must be exactly 32 bytes long (for mechanisms SHA256-RSA-PKCS-PSS there is no such restriction). For RSA-OAEP, the plaintext input size mLen must be at most keyLen - 2 - 2*hashLen. For example, for RSA 3072-bit key and SHA384, the longest plaintext to encrypt with RSA-OAEP is (with all sizes in bytes): 384 - 2 - 2*48 = 286, aka 286 bytes.

--id id, -d id

Specify the id of the object to operate on.


Initializes the user PIN. This option differs from --change-pin in that it sets the user PIN for the first time. Once set, the user PIN can be changed using --change-pin.


Initialize a token: set the token label as well as a Security Officer PIN (the label must be specified using --label).

--input-file filename, -i filename

Specify the path to a file for input.

--keypairgen, -k

Generate a new key pair (public and private pair.)


Generate a new key.

--key-type specification

Specify the type and length of the key to create, for example rsa:1024 or EC:prime256v1.


Specify 'sign' key usage flag (sets SIGN in privkey, sets VERIFY in pubkey).


Specify 'decrypt' key usage flag (RSA only, set DECRYPT privkey, ENCRYPT in pubkey).


Specify 'derive' key usage flag (EC only).


Specify 'wrap' key usage flag.

--label name, -a name

Specify the name of the object to operate on (or the token label when --init-token is used).

--list-mechanisms, -M

Display a list of mechanisms supported by the token.

--list-objects, -O

Display a list of objects.

--list-slots, -L

Display a list of available slots on the token.

--list-token-slots, -T

List slots with tokens.

--login, -l

Authenticate to the token before performing other operations. This option is not needed if a PIN is provided on the command line.


Specify login type ('so', 'user', 'context-specific'; default:'user').

--mechanism mechanism, -m mechanism

Use the specified mechanism for token operations. See -M for a list of mechanisms supported by your token. The mechanism can also be specified in hexadecimal, e.g., 0x80001234.

--mgf function

Use the specified Message Generation Function (MGF) function for RSA-PKCS-PSS signatures or RSA-OAEP decryptions. Supported arguments are MGF1-SHA1 to MGF1-SHA512 if supported by the driver. The default is based on the hash selection.

--module mod

Specify a PKCS#11 module (or library) to load.

--moz-cert filename, -z filename

Test a Mozilla-like key pair generation and certificate request. Specify the filename to the certificate file.

--output-file filename, -o filename

Specify the path to a file for output.

--pin pin, -p pin

Use the given pin for token operations. If set to env:VARIABLE, the value of the environment variable VARIABLE is used. WARNING: Be careful using this option as other users may be able to read the command line from the system or if it is embedded in a script. If set to env:VARIABLE, the value of the environment variable VARIABLE is used.

This option will also set the --login option.

--puk puk

Supply User PUK on the command line.

--new-pin pin

Supply new User PIN on the command line.


Set the CKA_SENSITIVE attribute (object cannot be revealed in plaintext).


Set the CKA_EXTRACTABLE attribute (object can be extracted)

--set-id id, -e id

Set the CKA_ID of the object.

--show-info, -I

Display general token information.

--sign, -s

Sign some data.


Decrypt some data.


Derive a secret key using another key and some data.


Derive ECDHpass DER encoded pubkey for compatibility with some PKCS#11 implementations

--salt-len bytes

Specify how many bytes of salt should be used in RSA-PSS signatures. Accepts two special values: "-1" means salt length equals to digest length, "-2" means use maximum permissible length. Default is digest length (-1).

--slot id

Specify the id of the slot to use.

--slot-description description

Specify the description of the slot to use.

--slot-index index

Specify the index of the slot to use.

--object-index index

Specify the index of the object to use.

--token-label label

Specify the label of token. Will be used the first slot, that has the inserted token with this label.

--so-pin pin

Use the given pin as the Security Officer PIN for some token operations (token initialization, user PIN initialization, etc). If set to env:VARIABLE, the value of the environment variable VARIABLE is used. The same warning as --pin also applies here.

--test, -t

Perform some tests on the token. This option is most useful when used with either --login or --pin.


Test hotplug capabilities (C_GetSlotList + C_WaitForSlotEvent).


Set the CKA_PRIVATE attribute (object is only viewable after a login).


Set the CKA_ALWAYS_AUTHENTICATE attribute to a private key object. If set, the user has to supply the PIN for each use (sign or decrypt) with the key.

--allowed-mechanisms mechanisms

Sets the CKA_ALLOWED_MECHANISMS attribute to a key objects when importing an object or generating a keys. The argument accepts comma-separated list of algorithmsm, that can be used with the given key.


Test EC (best used with the --login or --pin option).


Test forking and calling C_Initialize() in the child.

--type type, -y type

Specify the type of object to operate on. Valid value are cert, privkey, pubkey, secrkey and data.

--verbose, -v

Cause pkcs11-tool to be more verbose.

NB! This does not affect OpenSC debugging level! To set OpenSC PKCS#11 module into debug mode, set the OPENSC_DEBUG environment variable to a non-zero number.


Verify signature of some data.

--read-object, -r

Get object's CKA_VALUE attribute (use with --type).

--delete-object, -b

Delete an object.

--application-label label

Specify the application label of the data object (use with --type data).

--application-id id

Specify the application ID of the data object (use with --type data).

--issuer data

Specify the issuer in hexadecimal format (use with --type cert).

--subject data

Specify the subject in hexadecimal format (use with --type cert/privkey/pubkey).

--signature-file filename

The path to the signature file for signature verification

--signature-format format

Format for ECDSA signature: 'rs' (default), 'sequence', 'openssl'.

--write-object filename, -w filename

Write a key or certificate object to the token. filename points to the DER-encoded certificate or key file.

--generate-random num

Get num bytes of random data.


Allow using software mechanisms that do not have the CKF_HW flag set. May be required when using software tokens and emulators.


To list all certificates on the smart card:

pkcs11-tool --list-objects --type cert

To read the certificate with ID KEY_ID in DER format from smart card:

pkcs11-tool --read-object --id KEY_ID --type cert --output-file cert.der

To convert the certificate in DER format to PEM format, use OpenSSL tools:

openssl x509 -inform DER -in cert.der -outform PEM > cert.pem

To sign some data stored in file data using the private key with ID ID and using the RSA-PKCS mechanism:

pkcs11-tool --sign --id ID --mechanism RSA-PKCS --input-file data --output-file data.sig



pkcs11-tool was written by Olaf Kirch <>.