openssl/doc/apps/genpkey.pod

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2006-07-08 00:24:47 +00:00
=pod
=head1 NAME
genpkey - generate a private key
=head1 SYNOPSIS
B<openssl> B<genpkey>
[B<-out filename>]
[B<-outform PEM|DER>]
[B<-pass arg>]
[B<-cipher>]
[B<-engine id>]
[B<-paramfile file>]
[B<-algorithm alg>]
[B<-pkeyopt opt:value>]
[B<-genparam>]
[B<-text>]
=head1 DESCRIPTION
The B<genpkey> command generates a private key.
=head1 OPTIONS
=over 4
=item B<-out filename>
the output filename. If this argument is not specified then standard output is
used.
=item B<-outform DER|PEM>
This specifies the output format DER or PEM.
=item B<-pass arg>
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<-engine id>
specifying an engine (by it's unique B<id> string) will cause B<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.
=item B<-algorithm alg>
public key algorithm to use such as RSA, DSA or DH.
=item B<-pkeyopt opt:value>
set the public key algorithm option B<opt> to B<value>. The precise set of
options supported depends on the public key algorithm used and its
implementation. See B<KEY GENERATION OPTIONS> below for more details.
=item B<-genparam>
generate a set of parameters instead of a private key.
=item B<-paramfile filename>
Some public key algorithms generate a private key based on a set of parameters.
They can be supplied using this option. If this option is used the public
key algorithm used is determined by the parameters.
=back
=head1 KEY GENERATION OPTIONS
The options supported by each algorith and indeed each implementation of an
algorithm can vary. The options for the OpenSSL implementations are detailed
below.
=head1 RSA KEY GENERATION OPTIONS
=over 4
=item B<rsa_keygen_bits:numbits>
The number of bits in the generated key. If not specified 1024 is used.
=item B<rsa_keygen_pubexp:value>
The RSA public exponent value. This can be a large decimal or
hexadecimal value if preceded by B<0x>. Default value is 65537.
=back
=head1 DSA PARAMETER GENERATION OPTIONS
=over 4
=item B<dsa_paramgen_bits:numbits>
The number of bits in the generated parameters. If not specified 1024 is used.
=head1 DH PARAMETER GENERATION OPTIONS
=over 4
=item B<dh_paramgen_prime_len:numbits>
The number of bits in the prime parameter B<p>.
=item B<dh_paramgen_generator:value>
The value to use for the generator B<g>.
=back
=head1 EC PARAMETER GENERATION OPTIONS
=over 4
=item B<ec_paramgen_curve:curve>
the EC curve to use.
=back
=head1 NOTES
The use of the genpkey program is encouraged over the algorithm specific
utilities because additional algorithm options and ENGINE provided algorithms
can be used.
=head1 EXAMPLES
Generate an RSA private key using default parameters:
openssl genpkey -algoritm RSA -out key.pem
Encrypt output private key using 128 bit AES and the passphrase "hello":
openssl genpkey -algoritm RSA -out key.pem -aes-128-cbc -pass pass:hello
Generate a 2048 bit RSA key using 3 as the public exponent:
openssl genpkey -algoritm RSA -out key.pem -pkeyopt rsa_keygen_bits:2048 \
-pkeyopt rsa_keygen_pubexp:3
Generate 1024 bit DSA parameters:
openssl genpkey -genparam -algorithm DSA -out dsap.pem \
-pkeyopt dsa_paramgen_bits:1024
Generate DSA key from parameters:
openssl genpkey -paramfile dsap.pem -out dsakey.pem
Generate 1024 bit DH parameters:
openssl genpkey -genparam -algorithm DH -out dhp.pem \
-pkeyopt dh_paramgen_prime_len:1024
Generate DH key from parameters:
openssl genpkey -paramfile dhp.pem -out dhkey.pem
=cut