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Linux 2.6 - man page for pkcs8 (linux section 1SSL)

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PKCS8(1SSL)				     OpenSSL				      PKCS8(1SSL)

NAME
       pkcs8 - PKCS#8 format private key conversion tool

SYNOPSIS
       openssl pkcs8 [-topk8] [-inform PEM|DER] [-outform PEM|DER] [-in filename] [-passin arg]
       [-out filename] [-passout arg] [-noiter] [-nocrypt] [-nooct] [-embed] [-nsdb] [-v2 alg]
       [-v1 alg] [-engine id]

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.

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

       -inform DER|PEM
	   This specifies the input format. If a PKCS#8 format key is expected on input then
	   either a DER or PEM encoded version of a PKCS#8 key will be expected. Otherwise the
	   DER or PEM format of the traditional format private key is used.

       -outform DER|PEM
	   This specifies the output format, the options have the same meaning as the -inform
	   option.

       -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).

       -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.

       -nooct
	   This option generates RSA private keys in a broken format that some software uses.
	   Specifically the private key should be enclosed in a OCTET STRING but some software
	   just includes the structure itself without the surrounding OCTET STRING.

       -embed
	   This option generates DSA keys in a broken format. The DSA parameters are embedded
	   inside the PrivateKey structure. In this form the OCTET STRING contains an ASN1
	   SEQUENCE consisting of two structures: a SEQUENCE containing the parameters and an
	   ASN1 INTEGER containing the private key.

       -nsdb
	   This option generates DSA keys in a broken format compatible with Netscape private key
	   databases. The PrivateKey contains a SEQUENCE consisting of the public and private
	   keys respectively.

       -v2 alg
	   This option enables the use of PKCS#5 v2.0 algorithms. Normally PKCS#8 private keys
	   are encrypted with the password based encryption algorithm called pbeWithMD5AndDES-CBC
	   this uses 56 bit DES encryption but it was the strongest encryption algorithm
	   supported in PKCS#5 v1.5. Using the -v2 option PKCS#5 v2.0 algorithms are used which
	   can use any encryption algorithm such as 168 bit triple DES or 128 bit RC2 however not
	   many implementations support PKCS#5 v2.0 yet. If you are just using private keys with
	   OpenSSL then this doesn't matter.

	   The alg argument is the encryption algorithm to use, valid values include des, des3
	   and rc2. It is recommended that des3 is used.

       -v1 alg
	   This option specifies a PKCS#5 v1.5 or PKCS#12 algorithm to use. A complete list of
	   possible algorithms is included below.

       -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.

NOTES
       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.

       The default encryption is only 56 bits because this is the encryption that most current
       implementations of PKCS#8 will support.

       Some software may use PKCS#12 password based encryption algorithms with PKCS#8 format
       private keys: these are handled automatically but there is no option to produce them.

       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 from traditional 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#8 using a PKCS#5 1.5 compatible algorithm (DES):

	openssl pkcs8 -in key.pem -topk8 -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 format to traditional format:

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

       PKCS#8 using triple DES and PKCS#5 v2.0 should be the default private key format for
       OpenSSL: for compatibility several of the utilities use the old format at present.

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

1.0.0e					    2009-04-10				      PKCS8(1SSL)
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