PKCS12(1ssl)
NAME
pkcs12 - PKCS#12 file utility
SYNOPSIS
openssl pkcs12 [-export] [-chain] [-inkey filename] [-certfile filename] [-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
programs 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
information about the format of arg see the PASS PHRASE ARGUMENTS section 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 ARGUMENTS 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
software 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
output 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
certificate 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
certificates 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 signing only. Signing only keys can be used for S/MIME signing,
authenticode (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
algorithms. 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
passwords 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
supports 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
number generator, or an EGD socket (see RAND_egd(3)). Multiple files can be specified separated by a OS-dependent character. The separator 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
certificate 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 problem 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
algorithms 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
generation 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
certificates 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