Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
PKCS8(1)			    OpenSSL			      PKCS8(1)

NAME
       openssl-pkcs8, pkcs8 - PKCS#8 format private key	conversion tool

SYNOPSIS
       openssl pkcs8 [-help] [-topk8] [-inform PEM|DER]	[-outform PEM|DER]
       [-in filename] [-passin arg] [-out filename] [-passout arg] [-iter
       count] [-noiter]	[-rand file...]	 [-writerand file] [-nocrypt]
       [-traditional] [-v2 alg]	[-v2prf	alg] [-v1 alg] [-engine	id] [-scrypt]
       [-scrypt_N N] [-scrypt_r	r] [-scrypt_p p]

DESCRIPTION
       The pkcs8 command processes private keys	in PKCS#8 format. It can
       handle both unencrypted PKCS#8 PrivateKeyInfo format and
       EncryptedPrivateKeyInfo format with a variety of	PKCS#5 (v1.5 and v2.0)
       and PKCS#12 algorithms.

OPTIONS
       -help
	   Print out a usage message.

       -topk8
	   Normally a PKCS#8 private key is expected on	input and a private
	   key will be written to the output file. With	the -topk8 option the
	   situation is	reversed: it reads a private key and writes a PKCS#8
	   format key.

       -inform DER|PEM
	   This	specifies the input format: see	"KEY FORMATS" for more
	   details. The	default	format is PEM.

       -outform	DER|PEM
	   This	specifies the output format: see "KEY FORMATS" for more
	   details. The	default	format is PEM.

       -traditional
	   When	this option is present and -topk8 is not a traditional format
	   private key is written.

       -in filename
	   This	specifies the input filename to	read a key from	or standard
	   input if this option	is not specified. If the key is	encrypted a
	   pass	phrase will be prompted	for.

       -passin arg
	   The input file password source. For more information	about the
	   format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).

       -out filename
	   This	specifies the output filename to write a key to	or standard
	   output by default. If any encryption	options	are set	then a pass
	   phrase will be prompted for.	The output filename should not be the
	   same	as the input filename.

       -passout	arg
	   The output file password source. For	more information about the
	   format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).

       -iter count
	   When	creating new PKCS#8 containers,	use a given number of
	   iterations on the password in deriving the encryption key for the
	   PKCS#8 output.  High	values increase	the time required to brute-
	   force a PKCS#8 container.

       -nocrypt
	   PKCS#8 keys generated or input are normally PKCS#8
	   EncryptedPrivateKeyInfo structures using an appropriate password
	   based encryption algorithm. With this option	an unencrypted
	   PrivateKeyInfo structure is expected	or output.  This option	does
	   not encrypt private keys at all and should only be used when
	   absolutely necessary. Certain software such as some versions	of
	   Java	code signing software used unencrypted private keys.

       -rand file...
	   A file or files containing random data used to seed the random
	   number generator.  Multiple files can be specified separated	by an
	   OS-dependent	character.  The	separator is ; for MS-Windows, , for
	   OpenVMS, and	: for all others.

       [-writerand file]
	   Writes random data to the specified file upon exit.	This can be
	   used	with a subsequent -rand	flag.

       -v2 alg
	   This	option sets the	PKCS#5 v2.0 algorithm.

	   The alg argument is the encryption algorithm	to use,	valid values
	   include aes128, aes256 and des3. If this option isn't specified
	   then	aes256 is used.

       -v2prf alg
	   This	option sets the	PRF algorithm to use with PKCS#5 v2.0. A
	   typical value value would be	hmacWithSHA256.	If this	option isn't
	   set then the	default	for the	cipher is used or hmacWithSHA256 if
	   there is no default.

	   Some	implementations	may not	support	custom PRF algorithms and may
	   require the hmacWithSHA1 option to work.

       -v1 alg
	   This	option indicates a PKCS#5 v1.5 or PKCS#12 algorithm should be
	   used.  Some older implementations may not support PKCS#5 v2.0 and
	   may require this option.  If	not specified PKCS#5 v2.0 form is
	   used.

       -engine id
	   Specifying an engine	(by its	unique id string) will cause pkcs8 to
	   attempt to obtain a functional reference to the specified engine,
	   thus	initialising it	if needed. The engine will then	be set as the
	   default for all available algorithms.

       -scrypt
	   Uses	the scrypt algorithm for private key encryption	using default
	   parameters: currently N=16384, r=8 and p=1 and AES in CBC mode with
	   a 256 bit key. These	parameters can be modified using the
	   -scrypt_N, -scrypt_r, -scrypt_p and -v2 options.

       -scrypt_N N -scrypt_r r -scrypt_p p
	   Sets	the scrypt N, r	or p parameters.

KEY FORMATS
       Various different formats are used by the pkcs8 utility.	These are
       detailed	below.

       If a key	is being converted from	PKCS#8 form (i.e. the -topk8 option is
       not used) then the input	file must be in	PKCS#8 format. An encrypted
       key is expected unless -nocrypt is included.

       If -topk8 is not	used and PEM mode is set the output file will be an
       unencrypted private key in PKCS#8 format. If the	-traditional option is
       used then a traditional format private key is written instead.

       If -topk8 is not	used and DER mode is set the output file will be an
       unencrypted private key in traditional DER format.

       If -topk8 is used then any supported private key	can be used for	the
       input file in a format specified	by -inform. The	output file will be
       encrypted PKCS#8	format using the specified encryption parameters
       unless -nocrypt is included.

NOTES
       By default, when	converting a key to PKCS#8 format, PKCS#5 v2.0 using
       256 bit AES with	HMAC and SHA256	is used.

       Some older implementations do not support PKCS#5	v2.0 format and
       require the older PKCS#5	v1.5 form instead, possibly also requiring
       insecure	weak encryption	algorithms such	as 56 bit DES.

       The encrypted form of a PEM encode PKCS#8 files uses the	following
       headers and footers:

	-----BEGIN ENCRYPTED PRIVATE KEY-----
	-----END ENCRYPTED PRIVATE KEY-----

       The unencrypted form uses:

	-----BEGIN PRIVATE KEY-----
	-----END PRIVATE KEY-----

       Private keys encrypted using PKCS#5 v2.0	algorithms and high iteration
       counts are more secure that those encrypted using the traditional
       SSLeay compatible formats. So if	additional security is considered
       important the keys should be converted.

       It is possible to write out DER encoded encrypted private keys in
       PKCS#8 format because the encryption details are	included at an ASN1
       level whereas the traditional format includes them at a PEM level.

PKCS#5 v1.5 and	PKCS#12	algorithms.
       Various algorithms can be used with the -v1 command line	option,
       including PKCS#5	v1.5 and PKCS#12. These	are described in more detail
       below.

       PBE-MD2-DES PBE-MD5-DES
	   These algorithms were included in the original PKCS#5 v1.5
	   specification.  They	only offer 56 bits of protection since they
	   both	use DES.

       PBE-SHA1-RC2-64,	PBE-MD2-RC2-64,	PBE-MD5-RC2-64,	PBE-SHA1-DES
	   These algorithms are	not mentioned in the original PKCS#5 v1.5
	   specification but they use the same key derivation algorithm	and
	   are supported by some software. They	are mentioned in PKCS#5	v2.0.
	   They	use either 64 bit RC2 or 56 bit	DES.

       PBE-SHA1-RC4-128, PBE-SHA1-RC4-40, PBE-SHA1-3DES, PBE-SHA1-2DES,
       PBE-SHA1-RC2-128, PBE-SHA1-RC2-40
	   These algorithms use	the PKCS#12 password based encryption
	   algorithm and allow strong encryption algorithms like triple	DES or
	   128 bit RC2 to be used.

EXAMPLES
       Convert a private key to	PKCS#8 format using default parameters (AES
       with 256	bit key	and hmacWithSHA256):

	openssl	pkcs8 -in key.pem -topk8 -out enckey.pem

       Convert a private key to	PKCS#8 unencrypted format:

	openssl	pkcs8 -in key.pem -topk8 -nocrypt -out enckey.pem

       Convert a private key to	PKCS#5 v2.0 format using triple	DES:

	openssl	pkcs8 -in key.pem -topk8 -v2 des3 -out enckey.pem

       Convert a private key to	PKCS#5 v2.0 format using AES with 256 bits in
       CBC mode	and hmacWithSHA512 PRF:

	openssl	pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -v2prf	hmacWithSHA512 -out enckey.pem

       Convert a private key to	PKCS#8 using a PKCS#5 1.5 compatible algorithm
       (DES):

	openssl	pkcs8 -in key.pem -topk8 -v1 PBE-MD5-DES -out enckey.pem

       Convert a private key to	PKCS#8 using a PKCS#12 compatible algorithm
       (3DES):

	openssl	pkcs8 -in key.pem -topk8 -out enckey.pem -v1 PBE-SHA1-3DES

       Read a DER unencrypted PKCS#8 format private key:

	openssl	pkcs8 -inform DER -nocrypt -in key.der -out key.pem

       Convert a private key from any PKCS#8 encrypted format to traditional
       format:

	openssl	pkcs8 -in pk8.pem -traditional -out key.pem

       Convert a private key to	PKCS#8 format, encrypting with AES-256 and
       with one	million	iterations of the password:

	openssl	pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -iter 1000000 -out pk8.pem

STANDARDS
       Test vectors from this PKCS#5 v2.0 implementation were posted to	the
       pkcs-tng	mailing	list using triple DES, DES and RC2 with	high iteration
       counts, several people confirmed	that they could	decrypt	the private
       keys produced and Therefore it can be assumed that the PKCS#5 v2.0
       implementation is reasonably accurate at	least as far as	these
       algorithms are concerned.

       The format of PKCS#8 DSA	(and other) private keys is not	well
       documented: it is hidden	away in	PKCS#11	v2.01, section 11.9. OpenSSL's
       default DSA PKCS#8 private key format complies with this	standard.

BUGS
       There should be an option that prints out the encryption	algorithm in
       use and other details such as the iteration count.

SEE ALSO
       dsa(1), rsa(1), genrsa(1), gendsa(1)

HISTORY
       The -iter option	was added to OpenSSL 1.1.0.

COPYRIGHT
       Copyright 2000-2018 The OpenSSL Project Authors.	All Rights Reserved.

       Licensed	under the OpenSSL license (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>.

1.1.1a				  2018-11-20			      PKCS8(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | KEY FORMATS | NOTES | PKCS#5 v1.5 and PKCS#12 algorithms. | EXAMPLES | STANDARDS | BUGS | SEE ALSO | HISTORY | COPYRIGHT

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=pkcs8&sektion=1&manpath=FreeBSD+12.0-RELEASE+and+Ports>

home | help