# man > openssl-spkac(1)

[_OPENSSL-SPKAC_(1SSL)](https://www.chedong.com/phpMan.php/man/OPENSSL-SPKAC/1SSL/markdown)                            OpenSSL                           [_OPENSSL-SPKAC_(1SSL)](https://www.chedong.com/phpMan.php/man/OPENSSL-SPKAC/1SSL/markdown)

## NAME
       openssl-spkac - SPKAC printing and generating command

## SYNOPSIS
       **openssl spkac **[**-help**] [**-in _**filename_] [**-out _**filename_] [**-digest _**digest_] [**-key _**filename_|_uri_]
       [**-keyform DER**|**PEM**|**P12**|**ENGINE**] [**-passin _**arg_] [**-challenge _**string_] [**-pubkey**] [**-spkac _**spkacname_]
       [**-spksect _**section_] [**-noout**] [**-verify**] [**-engine _**id_] [**-provider _**name_] [**-provider-path _**path_]
       [**-propquery _**propq_]

## DESCRIPTION
       This command processes Netscape signed public key and challenge (SPKAC) files. It can print
       out their contents, verify the signature and produce its own SPKACs from a supplied private
       key.

## OPTIONS
### -help
           Print out a usage message.

### -in _
           This  specifies  the  input filename to read from or standard input if this option is not
           specified. Ignored if the **-key **option is used.

### -out _
           Specifies the output filename to write to or standard output by default.

### -digest _
           Use the specified _digest_ to sign a created SPKAC file.  The default digest  algorithm  is
           MD5.

### -key _
           Create  an  SPKAC  file  using  the  private  key specified by _filename_ or _uri_.  The **-in**,
           **-noout**, **-spksect **and **-verify **options are ignored if present.

### -keyform DER
           The key format; unspecified by default.  See [**openssl-format-options**(1)](https://www.chedong.com/phpMan.php/man/openssl-format-options/1/markdown) for details.

### -passin _
           The input file password source.  For  more  information  about  the  format  of  _arg_  see
           [**openssl-passphrase-options**(1)](https://www.chedong.com/phpMan.php/man/openssl-passphrase-options/1/markdown).

### -challenge _
           Specifies the challenge string if an SPKAC is being created.

### -spkac _
           Allows  an  alternative  name  form  the  variable  containing  the SPKAC. The default is
           "SPKAC". This option affects both generated and input SPKAC files.

### -spksect _
           Allows an alternative name form the section containing the  SPKAC.  The  default  is  the
           default section.

### -noout
           Don't output the text version of the SPKAC (not used if an SPKAC is being created).

### -pubkey
           Output the public key of an SPKAC (not used if an SPKAC is being created).

### -verify
           Verifies the digital signature on the supplied SPKAC.

### -engine _
           See "Engine Options" in [**openssl**(1)](https://www.chedong.com/phpMan.php/man/openssl/1/markdown).  This option is deprecated.

### -provider _
### -provider-path _
### -propquery _
           See "Provider Options" in [**openssl**(1)](https://www.chedong.com/phpMan.php/man/openssl/1/markdown), [**provider**(7)](https://www.chedong.com/phpMan.php/man/provider/7/markdown), and [**property**(7)](https://www.chedong.com/phpMan.php/man/property/7/markdown).

## EXAMPLES
       Print out the contents of an SPKAC:

        openssl spkac -in spkac.cnf

       Verify the signature of an SPKAC:

        openssl spkac -in spkac.cnf -noout -verify

       Create an SPKAC using the challenge string "hello":

        openssl spkac -key key.pem -challenge hello -out spkac.cnf

       Example of an SPKAC, (long lines split up for clarity):

        SPKAC=MIG5MGUwXDANBgkqhkiG9w0BAQEFAANLADBIAkEA\
        1cCoq2Wa3Ixs47uI7FPVwHVIPDx5yso105Y6zpozam135a\
        8R0CpoRvkkigIyXfcCjiVi5oWk+6FfPaD03uPFoQIDAQAB\
        FgVoZWxsbzANBgkqhkiG9w0BAQQFAANBAFpQtY/FojdwkJ\
        h1bEIYuc2EeM2KHTWPEepWYeawvHD0gQ3DngSC75YCWnnD\
        dq+NQ3F+X4deMx9AaEglZtULwV4=

## NOTES
       A created SPKAC with suitable DN components appended can be fed to [**openssl-ca**(1)](https://www.chedong.com/phpMan.php/man/openssl-ca/1/markdown).

       SPKACs are typically generated by Netscape when a form is submitted containing the **KEYGEN **tag
       as part of the certificate enrollment process.

       The  challenge  string  permits  a  primitive  form of proof of possession of private key. By
       checking the SPKAC signature and a random challenge string some guarantee is given  that  the
       user knows the private key corresponding to the public key being certified. This is important
       in  some  applications.  Without  this  it  is  possible for a previous SPKAC to be used in a
       "replay attack".

## SEE ALSO
       [**openssl**(1)](https://www.chedong.com/phpMan.php/man/openssl/1/markdown), [**openssl-ca**(1)](https://www.chedong.com/phpMan.php/man/openssl-ca/1/markdown)

## HISTORY
       The **-engine **option was deprecated in OpenSSL 3.0.

       The **-digest **option was added in OpenSSL 3.0.

## COPYRIGHT
       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file  except  in
       compliance  with  the  License.   You  can  obtain  a  copy in the file LICENSE in the source
       distribution or at <<https://www.openssl.org/source/license.html>>.

3.0.13                                       2026-07-29                          [_OPENSSL-SPKAC_(1SSL)](https://www.chedong.com/phpMan.php/man/OPENSSL-SPKAC/1SSL/markdown)