| =pod |
| |
| =head1 NAME |
| |
| openssl-genpkey, |
| genpkey - generate a private key |
| |
| =head1 SYNOPSIS |
| |
| B<openssl> B<genpkey> |
| [B<-help>] |
| [B<-out filename>] |
| [B<-outform PEM|DER>] |
| [B<-pass arg>] |
| [B<-I<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<-help> |
| |
| Print out a usage message. |
| |
| =item B<-out filename> |
| |
| Output the key to the specified file. If this argument is not specified then |
| standard output is used. |
| |
| =item B<-outform DER|PEM> |
| |
| This specifies the output format DER or PEM. The default format is 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)>. |
| |
| =item B<-I<cipher>> |
| |
| This option encrypts 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 its unique B<id> string) will cause B<genpkey> |
| 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. If used this option should precede all other |
| options. |
| |
| =item B<-algorithm alg> |
| |
| Public key algorithm to use such as RSA, DSA or DH. If used this option must |
| precede any B<-pkeyopt> options. The options B<-paramfile> and B<-algorithm> |
| are mutually exclusive. Engines may add algorithms in addition to the standard |
| built-in ones. |
| |
| Valid built-in algorithm names for private key generation are RSA, RSA-PSS, EC, |
| X25519, X448, ED25519 and ED448. |
| |
| Valid built-in algorithm names for parameter generation (see the B<-genparam> |
| option) are DH, DSA and EC. |
| |
| Note that the algorithm name X9.42 DH may be used as a synonym for the DH |
| algorithm. These are identical and do not indicate the type of parameters that |
| will be generated. Use the B<dh_paramgen_type> option to indicate whether PKCS#3 |
| or X9.42 DH parameters are required. See L<DH Parameter Generation Options> |
| below for more details. |
| |
| =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 L<KEY GENERATION OPTIONS> and |
| L<PARAMETER GENERATION OPTIONS> below for more details. |
| |
| =item B<-genparam> |
| |
| Generate a set of parameters instead of a private key. If used this option must |
| precede any B<-algorithm>, B<-paramfile> or B<-pkeyopt> options. |
| |
| =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. If used this option must |
| precede any B<-pkeyopt> options. The options B<-paramfile> and B<-algorithm> |
| are mutually exclusive. |
| |
| =item B<-text> |
| |
| Print an (unencrypted) text representation of private and public keys and |
| parameters along with the PEM or DER structure. |
| |
| =back |
| |
| =head1 KEY GENERATION OPTIONS |
| |
| The options supported by each algorithm and indeed each implementation of an |
| algorithm can vary. The options for the OpenSSL implementations are detailed |
| below. There are no key generation options defined for the X25519, X448, ED25519 |
| or ED448 algorithms. |
| |
| =head2 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_primes:numprimes> |
| |
| The number of primes in the generated key. If not specified 2 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 |
| |
| =head2 RSA-PSS Key Generation Options |
| |
| Note: by default an B<RSA-PSS> key has no parameter restrictions. |
| |
| =over 4 |
| |
| =item B<rsa_keygen_bits:numbits>, B<rsa_keygen_primes:numprimes>, B<rsa_keygen_pubexp:value> |
| |
| These options have the same meaning as the B<RSA> algorithm. |
| |
| =item B<rsa_pss_keygen_md:digest> |
| |
| If set the key is restricted and can only use B<digest> for signing. |
| |
| =item B<rsa_pss_keygen_mgf1_md:digest> |
| |
| If set the key is restricted and can only use B<digest> as it's MGF1 |
| parameter. |
| |
| =item B<rsa_pss_keygen_saltlen:len> |
| |
| If set the key is restricted and B<len> specifies the minimum salt length. |
| |
| =back |
| |
| =head2 EC Key Generation Options |
| |
| The EC key generation options can also be used for parameter generation. |
| |
| =over 4 |
| |
| =item B<ec_paramgen_curve:curve> |
| |
| The EC curve to use. OpenSSL supports NIST curve names such as "P-256". |
| |
| =item B<ec_param_enc:encoding> |
| |
| The encoding to use for parameters. The "encoding" parameter must be either |
| "named_curve" or "explicit". The default value is "named_curve". |
| |
| =back |
| |
| =head1 PARAMETER GENERATION OPTIONS |
| |
| The options supported by each algorithm and indeed each implementation of an |
| algorithm can vary. The options for the OpenSSL implementations are detailed |
| below. |
| |
| =head2 DSA Parameter Generation Options |
| |
| =over 4 |
| |
| =item B<dsa_paramgen_bits:numbits> |
| |
| The number of bits in the generated prime. If not specified 1024 is used. |
| |
| =item B<dsa_paramgen_q_bits:numbits> |
| |
| The number of bits in the q parameter. Must be one of 160, 224 or 256. If not |
| specified 160 is used. |
| |
| =item B<dsa_paramgen_md:digest> |
| |
| The digest to use during parameter generation. Must be one of B<sha1>, B<sha224> |
| or B<sha256>. If set, then the number of bits in B<q> will match the output size |
| of the specified digest and the B<dsa_paramgen_q_bits> parameter will be |
| ignored. If not set, then a digest will be used that gives an output matching |
| the number of bits in B<q>, i.e. B<sha1> if q length is 160, B<sha224> if it 224 |
| or B<sha256> if it is 256. |
| |
| =back |
| |
| =head2 DH Parameter Generation Options |
| |
| =over 4 |
| |
| =item B<dh_paramgen_prime_len:numbits> |
| |
| The number of bits in the prime parameter B<p>. The default is 1024. |
| |
| =item B<dh_paramgen_subprime_len:numbits> |
| |
| The number of bits in the sub prime parameter B<q>. The default is 256 if the |
| prime is at least 2048 bits long or 160 otherwise. Only relevant if used in |
| conjunction with the B<dh_paramgen_type> option to generate X9.42 DH parameters. |
| |
| =item B<dh_paramgen_generator:value> |
| |
| The value to use for the generator B<g>. The default is 2. |
| |
| =item B<dh_paramgen_type:value> |
| |
| The type of DH parameters to generate. Use 0 for PKCS#3 DH and 1 for X9.42 DH. |
| The default is 0. |
| |
| =item B<dh_rfc5114:num> |
| |
| If this option is set, then the appropriate RFC5114 parameters are used |
| instead of generating new parameters. The value B<num> can take the |
| values 1, 2 or 3 corresponding to RFC5114 DH parameters consisting of |
| 1024 bit group with 160 bit subgroup, 2048 bit group with 224 bit subgroup |
| and 2048 bit group with 256 bit subgroup as mentioned in RFC5114 sections |
| 2.1, 2.2 and 2.3 respectively. If present this overrides all other DH parameter |
| options. |
| |
| =back |
| |
| =head2 EC Parameter Generation Options |
| |
| The EC parameter generation options are the same as for key generation. See |
| L<EC Key Generation Options> above. |
| |
| =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 -algorithm RSA -out key.pem |
| |
| Encrypt output private key using 128 bit AES and the passphrase "hello": |
| |
| openssl genpkey -algorithm RSA -out key.pem -aes-128-cbc -pass pass:hello |
| |
| Generate a 2048 bit RSA key using 3 as the public exponent: |
| |
| openssl genpkey -algorithm RSA -out key.pem \ |
| -pkeyopt rsa_keygen_bits:2048 -pkeyopt rsa_keygen_pubexp:3 |
| |
| Generate 2048 bit DSA parameters: |
| |
| openssl genpkey -genparam -algorithm DSA -out dsap.pem \ |
| -pkeyopt dsa_paramgen_bits:2048 |
| |
| Generate DSA key from parameters: |
| |
| openssl genpkey -paramfile dsap.pem -out dsakey.pem |
| |
| Generate 2048 bit DH parameters: |
| |
| openssl genpkey -genparam -algorithm DH -out dhp.pem \ |
| -pkeyopt dh_paramgen_prime_len:2048 |
| |
| Generate 2048 bit X9.42 DH parameters: |
| |
| openssl genpkey -genparam -algorithm DH -out dhpx.pem \ |
| -pkeyopt dh_paramgen_prime_len:2048 \ |
| -pkeyopt dh_paramgen_type:1 |
| |
| Output RFC5114 2048 bit DH parameters with 224 bit subgroup: |
| |
| openssl genpkey -genparam -algorithm DH -out dhp.pem -pkeyopt dh_rfc5114:2 |
| |
| Generate DH key from parameters: |
| |
| openssl genpkey -paramfile dhp.pem -out dhkey.pem |
| |
| Generate EC parameters: |
| |
| openssl genpkey -genparam -algorithm EC -out ecp.pem \ |
| -pkeyopt ec_paramgen_curve:secp384r1 \ |
| -pkeyopt ec_param_enc:named_curve |
| |
| Generate EC key from parameters: |
| |
| openssl genpkey -paramfile ecp.pem -out eckey.pem |
| |
| Generate EC key directly: |
| |
| openssl genpkey -algorithm EC -out eckey.pem \ |
| -pkeyopt ec_paramgen_curve:P-384 \ |
| -pkeyopt ec_param_enc:named_curve |
| |
| Generate an X25519 private key: |
| |
| openssl genpkey -algorithm X25519 -out xkey.pem |
| |
| Generate an ED448 private key: |
| |
| openssl genpkey -algorithm ED448 -out xkey.pem |
| |
| =head1 HISTORY |
| |
| The ability to use NIST curve names, and to generate an EC key directly, |
| were added in OpenSSL 1.0.2. The ability to generate X25519 keys was added in |
| OpenSSL 1.1.0. The ability to generate X448, ED25519 and ED448 keys was added in |
| OpenSSL 1.1.1. |
| |
| =head1 COPYRIGHT |
| |
| Copyright 2006-2018 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 |