NAME
    pkcs8 - PKCS#8 format private key conversion tool

SYNOPSIS
    openssl pkcs8 [-topk8] [-inform PEM|DER] [-outform PEM|DER] [-in file-
    name] [-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 han-
    dle both unencrypted PKCS#8 PrivateKeyInfo format and EncryptedPri-
    vateKeyInfo 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 tradi-
   tional 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 tradi-
   tional 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 for-
   mat 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 EncryptedPri-
   vateKeyInfo structures using an appropriate password based encryp-
   tion algorithm. With this option an unencrypted PrivateKeyInfo
   structure is expected or output. This option does not encrypt pri-
   vate keys at all and should only be used when absolutely necessary.
   Certain software such as some versions of Java code signing soft-
   ware 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 parame-
   ters are embedded inside the PrivateKey structure. In this form the
   OCTET STRING contains an ASN1 SEQUENCE consisting of two struc-
   tures: 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 encryp-
   tion 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 it's unique id string) will cause req 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 specifi-
   cation. 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 algo-
   rithm 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 algo-
    rithms are concerned.

    The format of PKCS#8 DSA (and other) private keys is not well docu-
    mented: 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)