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]


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

           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

           algorithms is included below.


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

           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.

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


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