=pod

=head1 NAME

pkey - public or private key processing tool

=head1 SYNOPSIS

B<openssl> B<pkey>
[B<-inform PEM|DER>]
[B<-outform PEM|DER>]
[B<-in filename>]
[B<-passin arg>]
[B<-out filename>]
[B<-passout arg>]
[B<-cipher>]
[B<-text>]
[B<-text_pub>]
[B<-noout>]
[B<-pubin>]
[B<-pubout>]
[B<-engine id>]

=head1 DESCRIPTION

The B<pkey> command processes public or private keys. They can be converted
between various forms and their components printed out.

=head1 COMMAND OPTIONS

=over 4

=item B<-inform DER|PEM>

This specifies the input format DER or PEM.

=item B<-outform DER|PEM>

This specifies the output format, the options have the same meaning as the 
B<-inform> option.

=item B<-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.

=item B<-passin arg>

the input file password source. For more information about the format of B<arg>
see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.

=item B<-out filename>

This specifies the output filename to write a key to or standard output if this
option is not specified. If any encryption options are set then a pass phrase
will be prompted for. The output filename should B<not> be the same as the input
filename.

=item B<-passout password>

the output file password source. For more information about the format of B<arg>
see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.

=item B<-cipher>

These options encrypt the private key with the supplied cipher. Any algorithm
name accepted by EVP_get_cipherbyname() is acceptable such as B<des3>.

=item B<-text>

prints out the various public or private key components in
plain text in addition to the encoded version. 

=item B<-text_pub>

print out only public key components even if a private key is being processed.

=item B<-noout>

do not output the encoded version of the key.

=item B<-pubin>

by default a private key is read from the input file: with this
option a public key is read instead.

=item B<-pubout>

by default a private key is output: with this option a public
key will be output instead. This option is automatically set if
the input is a public key.

=item B<-engine id>

specifying an engine (by its unique B<id> string) will cause B<pkey>
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.

=back

=head1 EXAMPLES

To remove the pass phrase on an RSA private key:

 openssl pkey -in key.pem -out keyout.pem

To encrypt a private key using triple DES:

 openssl pkey -in key.pem -des3 -out keyout.pem

To convert a private key from PEM to DER format: 

 openssl pkey -in key.pem -outform DER -out keyout.der

To print out the components of a private key to standard output:

 openssl pkey -in key.pem -text -noout

To print out the public components of a private key to standard output:

 openssl pkey -in key.pem -text_pub -noout

To just output the public part of a private key:

 openssl pkey -in key.pem -pubout -out pubkey.pem

=head1 SEE ALSO

L<genpkey(1)|genpkey(1)>, L<rsa(1)|rsa(1)>, L<pkcs8(1)|pkcs8(1)>,
L<dsa(1)|dsa(1)>, L<genrsa(1)|genrsa(1)>, L<gendsa(1)|gendsa(1)> 

=cut