or B parameters.
=back
=head1 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.
=head1 PKCS#5 v1.5 and PKCS#12 algorithms.
Various algorithms can be used with the B<-v1> command line option,
including PKCS#5 v1.5 and PKCS#12. These are described in more detail
below.
=over 4
=item B
These algorithms were included in the original PKCS#5 v1.5 specification.
They only offer 56 bits of protection since they both use DES.
=item B
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.
=item B
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.
=back
=head1 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 from traditional to PKCS#5 v2.0 format using AES with
256 bits in CBC mode and B PRF:
openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA256 -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
Convert a private key to PKCS#8 format, encrypting with AES-256 and with
one million iterations of the password:
openssl pkcs8 -in raw.pem -topk8 -v2 aes-256-cbc -iter 1000000 -out pk8.pem
=head1 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.
=head1 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.
=head1 SEE ALSO
L, L, L,
L
=head1 HISTORY
The B<-iter> option was added to OpenSSL 1.1.0.
=cut