pkcs12
PKCS12(1) OpenSSL PKCS12(1)
NAME
pkcs12 - PKCS#12 file utility
SYNOPSIS
openssl pkcs12 [-export] [-chain] [-inkey filename] [-certfile file-
name] [-name name] [-caname name] [-in filename] [-out filename]
[-noout] [-nomacver] [-nocerts] [-clcerts] [-cacerts] [-nokeys] [-info]
[-des] [-des3] [-idea] [-nodes] [-noiter] [-maciter] [-twopass]
[-descert] [-certpbe] [-keypbe] [-keyex] [-keysig] [-password arg]
[-passin arg] [-passout arg] [-rand file(s)]
DESCRIPTION
The pkcs12 command allows PKCS#12 files (sometimes referred to as PFX
files) to be created and parsed. PKCS#12 files are used by several pro-
grams including Netscape, MSIE and MS Outlook.
COMMAND OPTIONS
There are a lot of options the meaning of some depends of whether a
PKCS#12 file is being created or parsed. By default a PKCS#12 file is
parsed a PKCS#12 file can be created by using the -export option (see
below).
PARSING OPTIONS
-in filename
This specifies filename of the PKCS#12 file to be parsed. Standard
input is used by default.
-out filename
The filename to write certificates and private keys to, standard
output by default. They are all written in PEM format.
-pass arg, -passin arg
the PKCS#12 file (i.e. input file) password source. For more infor-
mation about the format of arg see the PASS PHRASE ARGUMENTS sec-
tion in openssl(1).
-passout arg
pass phrase source to encrypt any outputed private keys with. For
more information about the format of arg see the PASS PHRASE ARGU-
MENTS section in openssl(1).
-noout
this option inhibits output of the keys and certificates to the
output file version of the PKCS#12 file.
-clcerts
only output client certificates (not CA certificates).
-cacerts
only output CA certificates (not client certificates).
-nocerts
no certificates at all will be output.
-nokeys
no private keys will be output.
-info
output additional information about the PKCS#12 file structure,
algorithms used and iteration counts.
-des
use DES to encrypt private keys before outputting.
-des3
use triple DES to encrypt private keys before outputting, this is
the default.
-idea
use IDEA to encrypt private keys before outputting.
-nodes
don't encrypt the private keys at all.
-nomacver
don't attempt to verify the integrity MAC before reading the file.
-twopass
prompt for separate integrity and encryption passwords: most soft-
ware always assumes these are the same so this option will render
such PKCS#12 files unreadable.
FILE CREATION OPTIONS
-export
This option specifies that a PKCS#12 file will be created rather
than parsed.
-out filename
This specifies filename to write the PKCS#12 file to. Standard out-
put is used by default.
-in filename
The filename to read certificates and private keys from, standard
input by default. They must all be in PEM format. The order
doesn't matter but one private key and its corresponding certifi-
cate should be present. If additional certificates are present they
will also be included in the PKCS#12 file.
-inkey filename
file to read private key from. If not present then a private key
must be present in the input file.
-name friendlyname
This specifies the "friendly name" for the certificate and private
key. This name is typically displayed in list boxes by software
importing the file.
-certfile filename
A filename to read additional certificates from.
-caname friendlyname
This specifies the "friendly name" for other certificates. This
option may be used multiple times to specify names for all certifi-
cates in the order they appear. Netscape ignores friendly names on
other certificates whereas MSIE displays them.
-pass arg, -passout arg
the PKCS#12 file (i.e. output file) password source. For more
information about the format of arg see the PASS PHRASE ARGUMENTS
section in openssl(1).
-passin password
pass phrase source to decrypt any input private keys with. For more
information about the format of arg see the PASS PHRASE ARGUMENTS
section in openssl(1).
-chain
if this option is present then an attempt is made to include the
entire certificate chain of the user certificate. The standard CA
store is used for this search. If the search fails it is considered
a fatal error.
-descert
encrypt the certificate using triple DES, this may render the
PKCS#12 file unreadable by some "export grade" software. By default
the private key is encrypted using triple DES and the certificate
using 40 bit RC2.
-keypbe alg, -certpbe alg
these options allow the algorithm used to encrypt the private key
and certificates to be selected. Although any PKCS#5 v1.5 or
PKCS#12 algorithms can be selected it is advisable only to use
PKCS#12 algorithms. See the list in the NOTES section for more
information.
-keyex|-keysig
specifies that the private key is to be used for key exchange or
just signing. This option is only interpreted by MSIE and similar
MS software. Normally "export grade" software will only allow 512
bit RSA keys to be used for encryption purposes but arbitrary
length keys for signing. The -keysig option marks the key for sign-
ing only. Signing only keys can be used for S/MIME signing, authen-
ticode (ActiveX control signing) and SSL client authentication,
however due to a bug only MSIE 5.0 and later support the use of
signing only keys for SSL client authentication.
-nomaciter, -noiter
these options affect the iteration counts on the MAC and key algo-
rithms. Unless you wish to produce files compatible with MSIE 4.0
you should leave these options alone.
To discourage attacks by using large dictionaries of common pass-
words the algorithm that derives keys from passwords can have an
iteration count applied to it: this causes a certain part of the
algorithm to be repeated and slows it down. The MAC is used to
check the file integrity but since it will normally have the same
password as the keys and certificates it could also be attacked.
By default both MAC and encryption iteration counts are set to
2048, using these options the MAC and encryption iteration counts
can be set to 1, since this reduces the file security you should
not use these options unless you really have to. Most software sup-
ports both MAC and key iteration counts. MSIE 4.0 doesn't support
MAC iteration counts so it needs the -nomaciter option.
-maciter
This option is included for compatibility with previous versions,
it used to be needed to use MAC iterations counts but they are now
used by default.
-rand file(s)
a file or files containing random data used to seed the random num-
ber generator, or an EGD socket (see RAND_egd(3)). Multiple files
can be specified separated by a OS-dependent character. The sepa-
rator is ; for MS-Windows, , for OpenVMS, and : for all others.
NOTES
Although there are a large number of options most of them are very
rarely used. For PKCS#12 file parsing only -in and -out need to be used
for PKCS#12 file creation -export and -name are also used.
If none of the -clcerts, -cacerts or -nocerts options are present then
all certificates will be output in the order they appear in the input
PKCS#12 files. There is no guarantee that the first certificate present
is the one corresponding to the private key. Certain software which
requires a private key and certificate and assumes the first certifi-
cate in the file is the one corresponding to the private key: this may
not always be the case. Using the -clcerts option will solve this prob-
lem by only outputting the certificate corresponding to the private
key. If the CA certificates are required then they can be output to a
separate file using the -nokeys -cacerts options to just output CA
certificates.
The -keypbe and -certpbe algorithms allow the precise encryption algo-
rithms for private keys and certificates to be specified. Normally the
defaults are fine but occasionally software can't handle triple DES
encrypted private keys, then the option -keypbe PBE-SHA1-RC2-40 can be
used to reduce the private key encryption to 40 bit RC2. A complete
description of all algorithms is contained in the pkcs8 manual page.
EXAMPLES
Parse a PKCS#12 file and output it to a file:
openssl pkcs12 -in file.p12 -out file.pem
Output only client certificates to a file:
openssl pkcs12 -in file.p12 -clcerts -out file.pem
Don't encrypt the private key:
openssl pkcs12 -in file.p12 -out file.pem -nodes
Print some info about a PKCS#12 file:
openssl pkcs12 -in file.p12 -info -noout
Create a PKCS#12 file:
openssl pkcs12 -export -in file.pem -out file.p12 -name "My Certificate"
Include some extra certificates:
openssl pkcs12 -export -in file.pem -out file.p12 -name "My Certificate" \
-certfile othercerts.pem
BUGS
Some would argue that the PKCS#12 standard is one big bug :-)
Versions of OpenSSL before 0.9.6a had a bug in the PKCS#12 key genera-
tion routines. Under rare circumstances this could produce a PKCS#12
file encrypted with an invalid key. As a result some PKCS#12 files
which triggered this bug from other implementations (MSIE or Netscape)
could not be decrypted by OpenSSL and similarly OpenSSL could produce
PKCS#12 files which could not be decrypted by other implementations.
The chances of producing such a file are relatively small: less than 1
in 256.
A side effect of fixing this bug is that any old invalidly encrypted
PKCS#12 files cannot no longer be parsed by the fixed version. Under
such circumstances the pkcs12 utility will report that the MAC is OK
but fail with a decryption error when extracting private keys.
This problem can be resolved by extracting the private keys and cer-
tificates from the PKCS#12 file using an older version of OpenSSL and
recreating the PKCS#12 file from the keys and certificates using a
newer version of OpenSSL. For example:
old-openssl -in bad.p12 -out keycerts.pem
openssl -in keycerts.pem -export -name "My PKCS#12 file" -out fixed.p12
SEE ALSO
pkcs8(1)
0.9.7a 2001-09-07 PKCS12(1)
