=item B<-outform DER|PEM>
-This specifies the output format, the options have the same meaning as the
+This specifies the output format, the options have the same meaning as the
B<-inform> option.
=item B<-in filename>
=item B<-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 B<pbeWithMD5AndDES-CBC> this uses 56 bit DES encryption but it
-was the strongest encryption algorithm supported in PKCS#5 v1.5. Using
-the B<-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.
+This option sets the PKCS#5 v2.0 algorithm.
The B<alg> argument is the encryption algorithm to use, valid values include
-B<des>, B<des3> and B<rc2>. It is recommended that B<des3> is used.
+B<aes128>, B<aes256> and B<des3>. If this option isn't specified then B<aes256>
+is used.
=item B<-v2prf alg>
This option sets the PRF algorithm to use with PKCS#5 v2.0. A typical value
-values would be B<hmacWithSHA256>. If this option isn't set then the default
-for the cipher is used or B<hmacWithSHA1> if there is no default.
+value would be B<hmacWithSHA256>. If this option isn't set then the default
+for the cipher is used or B<hmacWithSHA256> if there is no default.
+
+Some implementations may not support custom PRF algorithms and may require
+the B<hmacWithSHA1> option to work.
=item B<-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.
+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 for is used.
=item B<-engine id>
=head1 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:
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.
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
+
+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 SEE ALSO
L<dsa(1)>, L<rsa(1)>, L<genrsa(1)>,
-L<gendsa(1)>
+L<gendsa(1)>
=head1 HISTORY
The B<-iter> option was added to OpenSSL 1.1.0.
+=head1 COPYRIGHT
+
+Copyright 2000-2016 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
+L<https://www.openssl.org/source/license.html>.
+
=cut
projects / openssl.git / blobdiff